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Posted to commits@pulsar.apache.org by ur...@apache.org on 2022/06/20 18:05:23 UTC
[pulsar-site] branch main updated: Docs sync done from apache/pulsar(#159ead3)
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The following commit(s) were added to refs/heads/main by this push:
new f36cd85b23a Docs sync done from apache/pulsar(#159ead3)
f36cd85b23a is described below
commit f36cd85b23ae4b8adc5085b0e2439bdac3f0c4ca
Author: Pulsar Site Updater <de...@pulsar.apache.org>
AuthorDate: Mon Jun 20 18:05:18 2022 +0000
Docs sync done from apache/pulsar(#159ead3)
---
.../docs/administration-load-balance.md | 277 +++++++++++++--------
.../docs/concepts-architecture-overview.md | 2 +-
site2/website-next/docs/reference-terminology.md | 9 +
...-affinity-namespaces-across-failure-domains.svg | 1 +
.../version-2.10.0/administration-load-balance.md | 276 ++++++++++++--------
.../version-2.10.0/reference-terminology.md | 8 +
.../version-2.8.0/administration-load-balance.md | 56 +++++
.../version-2.8.0/reference-terminology.md | 8 +
.../version-2.8.1/administration-load-balance.md | 56 +++++
.../version-2.8.1/reference-terminology.md | 8 +
.../version-2.8.2/administration-load-balance.md | 56 +++++
.../version-2.8.2/reference-terminology.md | 8 +
.../version-2.8.3/administration-load-balance.md | 56 +++++
.../version-2.8.3/reference-terminology.md | 8 +
.../version-2.9.0/administration-load-balance.md | 56 +++++
.../version-2.9.0/reference-terminology.md | 8 +
.../version-2.9.1/administration-load-balance.md | 56 +++++
.../version-2.9.1/reference-terminology.md | 8 +
.../version-2.9.2/administration-load-balance.md | 56 +++++
.../version-2.9.2/reference-terminology.md | 8 +
20 files changed, 806 insertions(+), 215 deletions(-)
diff --git a/site2/website-next/docs/administration-load-balance.md b/site2/website-next/docs/administration-load-balance.md
index a9fd48348d9..f581c031cb4 100644
--- a/site2/website-next/docs/administration-load-balance.md
+++ b/site2/website-next/docs/administration-load-balance.md
@@ -1,110 +1,81 @@
---
id: administration-load-balance
-title: Pulsar load balance
+title: Load balance across brokers
sidebar_label: "Load balance"
---
-## Load balance across Pulsar brokers
-Pulsar is an horizontally scalable messaging system, so the traffic in a logical cluster must be balanced across all the available Pulsar brokers as evenly as possible, which is a core requirement.
+Pulsar is a horizontally scalable messaging system, so the traffic in a logical cluster must be balanced across all the available Pulsar brokers as evenly as possible, which is a core requirement.
-You can use multiple settings and tools to control the traffic distribution which require a bit of context to understand how the traffic is managed in Pulsar. Though, in most cases, the core requirement mentioned above is true out of the box and you should not worry about it.
+You can use multiple settings and tools to control the traffic distribution which requires a bit of context to understand how the traffic is managed in Pulsar. Though in most cases, the core requirement mentioned above is true out of the box and you should not worry about it.
-## Pulsar load manager architecture
+The following sections introduce how the load-balanced assignments work across Pulsar brokers and how you can leverage the framework to adjust.
-The following part introduces the basic architecture of the Pulsar load manager.
+## Dynamic assignments
-### Assign topics to brokers dynamically
+Topics are dynamically assigned to brokers based on the load conditions of all brokers in the cluster. The assignment of topics to brokers is not done at the topic level but at the **bundle** level (a higher level). Instead of individual topic assignments, each broker takes ownership of a subset of the topics for a namespace. This subset is called a bundle and effectively this subset is a sharding mechanism.
-Topics are dynamically assigned to brokers based on the load conditions of all brokers in the cluster.
+In other words, each namespace is an "administrative" unit and sharded into a list of bundles, with each bundle comprising a portion of the overall hash range of the namespace. Topics are assigned to a particular bundle by taking the hash of the topic name and checking in which bundle the hash falls. Each bundle is independent of the others and thus is independently assigned to different brokers.
-When a client starts using new topics that are not assigned to any broker, a process is triggered to choose the best suited broker to acquire ownership of these topics according to the load conditions.
+The benefit of the assignment granularity is to amortize the amount of information that you need to keep track of. Based on CPU, memory, traffic load, and other indexes, topics are assigned to a particular broker dynamically. For example:
+* When a client starts using new topics that are not assigned to any broker, a process is triggered to choose the best-suited broker to acquire ownership of these topics according to the load conditions.
+* If the broker owning a topic becomes overloaded, the topic is reassigned to a less-loaded broker.
+* If the broker owning a topic crashes, the topic is reassigned to another active broker.
-In case of partitioned topics, different partitions are assigned to different brokers. Here "topic" means either a non-partitioned topic or one partition of a topic.
+:::tip
-The assignment is "dynamic" because the assignment changes quickly. For example, if the broker owning the topic crashes, the topic is reassigned immediately to another broker. Another scenario is that the broker owning the topic becomes overloaded. In this case, the topic is reassigned to a less loaded broker.
+For partitioned topics, different partitions are assigned to different brokers. Here "topic" means either a non-partitioned topic or one partition of a topic.
-The stateless nature of brokers makes the dynamic assignment possible, so you can quickly expand or shrink the cluster based on usage.
+:::
-#### Assignment granularity
+## Create namespaces with assigned bundles
-The assignment of topics or partitions to brokers is not done at the topics or partitions level, but done at the Bundle level (a higher level). The reason is to amortize the amount of information that you need to keep track. Based on CPU, memory, traffic load and other indexes, topics are assigned to a particular broker dynamically.
+When you create a new namespace, a number of bundles are assigned to the namespace. You can set this number in the `conf/broker.conf` file:
-Instead of individual topic or partition assignment, each broker takes ownership of a subset of the topics for a namespace. This subset is called a "*bundle*" and effectively this subset is a sharding mechanism.
+```conf
-The namespace is the "administrative" unit: many config knobs or operations are done at the namespace level.
-
-For assignment, a namespaces is sharded into a list of "bundles", with each bundle comprising a portion of overall hash range of the namespace.
-
-Topics are assigned to a particular bundle by taking the hash of the topic name and checking in which bundle the hash falls into.
-
-Each bundle is independent of the others and thus is independently assigned to different brokers.
-
-### Create namespaces and bundles
-
-When you create a new namespace, the new namespace sets to use the default number of bundles. You can set this in `conf/broker.conf`:
-
-```properties
-
-# When a namespace is created without specifying the number of bundle, this
+# When a namespace is created without specifying the number of bundles, this
# value will be used as the default
defaultNumberOfNamespaceBundles=4
```
-You can either change the system default, or override it when you create a new namespace:
+Alternatively, you can override the value when you create a new namespace using [Pulsar admin](/tools/pulsar-admin/):
```shell
-$ bin/pulsar-admin namespaces create my-tenant/my-namespace --clusters us-west --bundles 16
+bin/pulsar-admin namespaces create my-tenant/my-namespace --clusters us-west --bundles 16
```
-With this command, you create a namespace with 16 initial bundles. Therefore the topics for this namespaces can immediately be spread across up to 16 brokers.
+With the above command, you create a namespace with 16 initial bundles. Therefore the topics for this namespace can immediately be spread across up to 16 brokers.
In general, if you know the expected traffic and number of topics in advance, you had better start with a reasonable number of bundles instead of waiting for the system to auto-correct the distribution.
-On the same note, it is beneficial to start with more bundles than the number of brokers, because of the hashing nature of the distribution of topics into bundles. For example, for a namespace with 1000 topics, using something like 64 bundles achieves a good distribution of traffic across 16 brokers.
-
-### Unload topics and bundles
-
-You can "unload" a topic in Pulsar with admin operation. Unloading means to close the topics, release ownership and reassign the topics to a new broker, based on current load.
-
-When unloading happens, the client experiences a small latency blip, typically in the order of tens of milliseconds, while the topic is reassigned.
-
-Unloading is the mechanism that the load-manager uses to perform the load shedding, but you can also trigger the unloading manually, for example to correct the assignments and redistribute traffic even before having any broker overloaded.
+On the same note, it is beneficial to start with more bundles than the number of brokers, due to the hashing nature of the distribution of topics into bundles. For example, for a namespace with 1000 topics, using something like 64 bundles achieves a good distribution of traffic across 16 brokers.
-Unloading a topic has no effect on the assignment, but just closes and reopens the particular topic:
-```shell
+## Split namespace bundles
-pulsar-admin topics unload persistent://tenant/namespace/topic
+Since the load for the topics in a bundle might change over time and predicting the load might be hard, bundle split is designed to resolve these challenges. The broker splits a bundle into two and the new smaller bundles can be reassigned to different brokers.
-```
+Pulsar supports the following two bundle split algorithms:
+* `range_equally_divide`: split the bundle into two parts with the same hash range size.
+* `topic_count_equally_divide`: split the bundle into two parts with the same number of topics.
-To unload all topics for a namespace and trigger reassignments:
+To enable bundle split, you need to configure the following settings in the `broker.conf` file, and set `defaultNamespaceBundleSplitAlgorithm` based on your needs.
-```shell
+```conf
-pulsar-admin namespaces unload tenant/namespace
+loadBalancerAutoBundleSplitEnabled=true
+loadBalancerAutoUnloadSplitBundlesEnabled=true
+defaultNamespaceBundleSplitAlgorithm=range_equally_divide
```
-### Split namespace bundles
-
-Since the load for the topics in a bundle might change over time and predicting the load might be hard, bundle split is designed to deal with these issues. The broker splits a bundle into two and the new smaller bundles can be reassigned to different brokers.
+You can configure more parameters for splitting thresholds. Any existing bundle that exceeds any of the thresholds is a candidate to be split. By default, the newly split bundles are immediately reassigned to other brokers, to facilitate the traffic distribution.
-The splitting is based on some tunable thresholds. Any existing bundle that exceeds any of the threshold is a candidate to be split. By default the newly split bundles are also immediately offloaded to other brokers, to facilitate the traffic distribution.
-
-You can split namespace bundles in two ways, by setting `supportedNamespaceBundleSplitAlgorithms` to `range_equally_divide` or `topic_count_equally_divide` in `broker.conf` file. The former splits the bundle into two parts with the same hash range size; the latter splits the bundle into two parts with the same number of topics. You can also configure other parameters for namespace bundles.
-
-```properties
-
-# enable/disable namespace bundle auto split
-loadBalancerAutoBundleSplitEnabled=true
-
-# enable/disable automatic unloading of split bundles
-loadBalancerAutoUnloadSplitBundlesEnabled=true
+```conf
# maximum topics in a bundle, otherwise bundle split will be triggered
loadBalancerNamespaceBundleMaxTopics=1000
@@ -123,94 +94,184 @@ loadBalancerNamespaceMaximumBundles=128
```
-### Shed load automatically
+## Shed load automatically
-The support for automatic load shedding is available in the load manager of Pulsar. This means that whenever the system recognizes a particular broker is overloaded, the system forces some traffic to be reassigned to less loaded brokers.
+The support for automatic load shedding is available in the load manager of Pulsar. This means that whenever the system recognizes a particular broker is overloaded, the system forces some traffic to be reassigned to less-loaded brokers.
When a broker is identified as overloaded, the broker forces to "unload" a subset of the bundles, the ones with higher traffic, that make up for the overload percentage.
-For example, the default threshold is 85% and if a broker is over quota at 95% CPU usage, then the broker unloads the percent difference plus a 5% margin: `(95% - 85%) + 5% = 15%`.
+For example, the default threshold is 85% and if a broker is over quota at 95% CPU usage, then the broker unloads the percent difference plus a 5% margin: `(95% - 85%) + 5% = 15%`. Given the selection of bundles to unload is based on traffic (as a proxy measure for CPU, network, and memory), the broker unloads bundles for at least 15% of traffic.
-Given the selection of bundles to offload is based on traffic (as a proxy measure for cpu, network and memory), broker unloads bundles for at least 15% of traffic.
+:::tip
-The automatic load shedding is enabled by default and you can disable the automatic load shedding with this setting:
+* The automatic load shedding is enabled by default. To disable it, you can set `loadBalancerSheddingEnabled` to `false`.
+* Besides the automatic load shedding, you can [manually unload bundles](#unload-topics-and-bundles).
-```properties
-
-# Enable/disable automatic bundle unloading for load-shedding
-loadBalancerSheddingEnabled=true
-
-```
+:::
Additional settings that apply to shedding:
-```properties
+```conf
# Load shedding interval. Broker periodically checks whether some traffic should be offload from
# some over-loaded broker to other under-loaded brokers
loadBalancerSheddingIntervalMinutes=1
-# Prevent the same topics to be shed and moved to other brokers more that once within this timeframe
+# Prevent the same topics to be shed and moved to other brokers more than once within this timeframe
loadBalancerSheddingGracePeriodMinutes=30
```
-Pulsar supports the following types of shedding strategies. From Pulsar 2.10, the **default** shedding strategy is `ThresholdShedder`.
+Pulsar supports the following types of automatic load shedding strategies.
+* [ThresholdShedder](#thresholdshedder)
+* [OverloadShedder](#overloadshedder)
+* [UniformLoadShedder](#uniformloadshedder)
-> **Note**<br />
-> You need to restart brokers if the shedding strategy is [dynamically updated](admin-api-brokers.md/#dynamic-broker-configuration).
+:::note
-##### ThresholdShedder
-This strategy tends to shed the bundles if any broker's usage is above the configured threshold. It does this by first computing the average resource usage per broker for the whole cluster. The resource usage for each broker is calculated using the following method: LocalBrokerData#getMaxResourceUsageWithWeight. The weights for each resource are configurable. Historical observations are included in the running average based on the broker's setting for loadBalancerHistoryResourcePercentag [...]
-`loadBalancerLoadSheddingStrategy=org.apache.pulsar.broker.loadbalance.impl.ThresholdShedder`
+* From Pulsar 2.10, the **default** shedding strategy is `ThresholdShedder`.
+* You need to restart brokers if the shedding strategy is [dynamically updated](admin-api-brokers.md/#dynamic-broker-configuration).
+
+:::
+
+### ThresholdShedder
+This strategy tends to shed the bundles if any broker's usage is above the configured threshold. It does this by first computing the average resource usage per broker for the whole cluster. The resource usage for each broker is calculated using the following method `LocalBrokerData#getMaxResourceUsageWithWeight`. Historical observations are included in the running average based on the broker's setting for `loadBalancerHistoryResourcePercentage`. Once the average resource usage is calcula [...]
-##### OverloadShedder
-This strategy will attempt to shed exactly one bundle on brokers which are overloaded, that is, whose maximum system resource usage exceeds loadBalancerBrokerOverloadedThresholdPercentage. To see which resources are considered when determining the maximum system resource. A bundle is recommended for unloading off that broker if and only if the following conditions hold: The broker has at least two bundles assigned and the broker has at least one bundle that has not been unloaded recently [...]
-`loadBalancerLoadSheddingStrategy=org.apache.pulsar.broker.loadbalance.impl.OverloadShedder`
+To use the `ThresholdShedder` strategy, configure brokers with this value.
+`loadBalancerLoadSheddingStrategy=org.apache.pulsar.broker.loadbalance.impl.ThresholdShedder`
+
+You can configure the weights for each resource per broker in the `conf/broker.conf` file.
+
+```conf
+
+# The BandWithIn usage weight when calculating new resource usage.
+loadBalancerBandwithInResourceWeight=1.0
+
+# The BandWithOut usage weight when calculating new resource usage.
+loadBalancerBandwithOutResourceWeight=1.0
+
+# The CPU usage weight when calculating new resource usage.
+loadBalancerCPUResourceWeight=1.0
+
+# The heap memory usage weight when calculating new resource usage.
+loadBalancerMemoryResourceWeight=1.0
+
+# The direct memory usage weight when calculating new resource usage.
+loadBalancerDirectMemoryResourceWeight=1.0
+
+```
+
+### OverloadShedder
+This strategy attempts to shed exactly one bundle on brokers which are overloaded, that is, whose maximum system resource usage exceeds [`loadBalancerBrokerOverloadedThresholdPercentage`](#broker-overload-thresholds). To see which resources are considered when determining the maximum system resource. A bundle is recommended for unloading off that broker if and only if the following conditions hold: The broker has at least two bundles assigned and the broker has at least one bundle that h [...]
-##### UniformLoadShedder
-This strategy tends to distribute load uniformly across all brokers. This strategy checks load difference between broker with highest load and broker with lowest load. If the difference is higher than configured thresholds `loadBalancerMsgRateDifferenceShedderThreshold` and `loadBalancerMsgThroughputMultiplierDifferenceShedderThreshold` then it finds out bundles which can be unloaded to distribute traffic evenly across all brokers. Configure broker with below value to use this strategy.
-`loadBalancerLoadSheddingStrategy=org.apache.pulsar.broker.loadbalance.impl.UniformLoadShedder`
+To use the `OverloadShedder` strategy, configure brokers with this value.
+`loadBalancerLoadSheddingStrategy=org.apache.pulsar.broker.loadbalance.impl.OverloadShedder`
+
+#### Broker overload thresholds
+
+The determination of when a broker is overloaded is based on the threshold of CPU, network, and memory usage. Whenever either of those metrics reaches the threshold, the system triggers the shedding (if enabled).
+
+:::note
+
+The overload threshold `loadBalancerBrokerOverloadedThresholdPercentage` only applies to the [`OverloadShedder`](#overloadshedder) shedding strategy. By default, it is set to 85%.
+
+:::
+
+Pulsar gathers the CPU, network, and memory usage stats from the system metrics. In some cases of network utilization, the network interface speed that Linux reports is not correct and needs to be manually overridden. This is the case in AWS EC2 instances with 1Gbps NIC speed for which the OS reports 10Gbps speed.
+
+Because of the incorrect max speed, the load manager might think the broker has not reached the NIC capacity, while in fact the broker already uses all the bandwidth and the traffic is slowed down.
+
+You can set `loadBalancerOverrideBrokerNicSpeedGbps` in the `conf/broker.conf` file to correct the max NIC speed. When the value is empty, Pulsar uses the value that the OS reports.
+
+### UniformLoadShedder
+This strategy tends to distribute load uniformly across all brokers. This strategy checks the load difference between the broker with the highest load and the broker with the lowest load. If the difference is higher than configured thresholds `loadBalancerMsgRateDifferenceShedderThreshold` and `loadBalancerMsgThroughputMultiplierDifferenceShedderThreshold` then it finds out bundles that can be unloaded to distribute traffic evenly across all brokers.
-#### Broker overload thresholds
+To use the `UniformLoadShedder` strategy, configure brokers with this value.
+`loadBalancerLoadSheddingStrategy=org.apache.pulsar.broker.loadbalance.impl.UniformLoadShedder`
+
+## Unload topics and bundles
+
+You can "unload" a topic in Pulsar manual admin operations. Unloading means closing topics, releasing ownership, and reassigning topics to a new broker, based on the current load.
+
+When unloading happens, the client experiences a small latency blip, typically in the order of tens of milliseconds, while the topic is reassigned.
+
+Unloading is the mechanism that the load manager uses to perform the load shedding, but you can also trigger the unloading manually, for example, to correct the assignments and redistribute traffic even before having any broker overloaded.
+
+Unloading a topic has no effect on the assignment, but just closes and reopens the particular topic:
-The determinations of when a broker is overloaded is based on threshold of CPU, network and memory usage. Whenever either of those metrics reaches the threshold, the system triggers the shedding (if enabled).
+```shell
-By default, overload threshold is set at 85%:
+pulsar-admin topics unload persistent://tenant/namespace/topic
-```properties
+```
-# Usage threshold to determine a broker as over-loaded
-loadBalancerBrokerOverloadedThresholdPercentage=85
+To unload all topics for a namespace and trigger reassignments:
+
+```shell
+
+pulsar-admin namespaces unload tenant/namespace
```
-Pulsar gathers the usage stats from the system metrics.
+## Distribute anti-affinity namespaces across failure domains
+
+When your application has multiple namespaces and you want one of them available all the time to avoid any downtime, you can group these namespaces and distribute them across different [failure domains](reference-terminology.md#failure-domain) and different brokers. Thus, if one of the failure domains is down (due to release rollout or brokers restart), it only disrupts namespaces owned by that specific failure domain and the rest of the namespaces owned by other domains remain available [...]
+
+Such a group of namespaces has anti-affinity to each other, that is, all the namespaces in this group are [anti-affinity namespaces](reference-terminology.md#anti-affinity-namespaces) and are distributed to different failure domains in a load-balanced manner.
-In case of network utilization, in some cases the network interface speed that Linux reports is not correct and needs to be manually overridden. This is the case in AWS EC2 instances with 1Gbps NIC speed for which the OS reports 10Gbps speed.
+As illustrated in the following figure, Pulsar has 2 failure domains (Domain1 and Domain2) and each domain has 2 brokers in it. You can create an anti-affinity namespace group that has 4 namespaces in it, and all the 4 namespaces have anti-affinity to each other. The load manager tries to distribute namespaces evenly across all the brokers in the same domain. Since each domain has 2 brokers, every broker owns one namespace from this anti-affinity namespace group, and you can see each dom [...]
-Because of the incorrect max speed, the Pulsar load manager might think the broker has not reached the NIC capacity, while in fact the broker already uses all the bandwidth and the traffic is slowed down.
+
-You can use the following setting to correct the max NIC speed:
+The load manager follows an even distribution policy across failure domains to assign anti-affinity namespaces. The following table outlines the even-distributed assignment sequence illustrated in the above figure.
-```properties
+| Assignment sequence | Namespace | Failure domain candidates | Broker candidates | Selected broker |
+|:---|:------------|:------------------|:------------------------------------|:-----------------|
+| 1 | Namespace1 | Domain1, Domain2 | Broker1, Broker2, Broker3, Broker4 | Domain1:Broker1 |
+| 2 | Namespace2 | Domain2 | Broker3, Broker4 | Domain2:Broker3 |
+| 3 | Namespace3 | Domain1, Domain2 | Broker2, Broker4 | Domain1:Broker2 |
+| 4 | Namespace4 | Domain2 | Broker4 | Domain2:Broker4 |
+
+:::tip
-# Override the auto-detection of the network interfaces max speed.
-# This option is useful in some environments (eg: EC2 VMs) where the max speed
-# reported by Linux is not reflecting the real bandwidth available to the broker.
-# Since the network usage is employed by the load manager to decide when a broker
-# is overloaded, it is important to make sure the info is correct or override it
-# with the right value here. The configured value can be a double (eg: 0.8) and that
-# can be used to trigger load-shedding even before hitting on NIC limits.
-loadBalancerOverrideBrokerNicSpeedGbps=
+* Each namespace belongs to only one anti-affinity group. If a namespace with an existing anti-affinity assignment is assigned to another anti-affinity group, the original assignment is dropped.
+
+* If there are more anti-affinity namespaces than failure domains, the load manager distributes namespaces evenly across all the domains, and also every domain distributes namespaces evenly across all the brokers under that domain.
+
+:::
+
+### Create a failure domain and register brokers
+
+:::note
+
+One broker can only be registered to a single failure domain.
+
+:::
+
+To create a domain under a specific cluster and register brokers, run the following command:
+
+```bash
+
+pulsar-admin clusters create-failure-domain <cluster-name> --domain-name <domain-name> --broker-list <broker-list-comma-separated>
```
-When the value is empty, Pulsar uses the value that the OS reports.
+You can also view, update, and delete domains under a specific cluster. For more information, refer to [Pulsar admin doc](/tools/pulsar-admin/).
+
+### Create an anti-affinity namespace group
+
+An anti-affinity group is created automatically when the first namespace is assigned to the group. To assign a namespace to an anti-affinity group, run the following command. It sets an anti-affinity group name for a namespace.
+
+```bash
+
+pulsar-admin namespaces set-anti-affinity-group <namespace> --group <group-name>
+
+```
+For more information about `anti-affinity-group` related commands, refer to [Pulsar admin doc](/tools/pulsar-admin/).
diff --git a/site2/website-next/docs/concepts-architecture-overview.md b/site2/website-next/docs/concepts-architecture-overview.md
index 19e84f93eaa..1384b3ed4bf 100644
--- a/site2/website-next/docs/concepts-architecture-overview.md
+++ b/site2/website-next/docs/concepts-architecture-overview.md
@@ -8,7 +8,7 @@ At the highest level, a Pulsar instance is composed of one or more Pulsar cluste
In a Pulsar cluster:
-* One or more brokers handles and [load balances](administration-load-balance.md#load-balance-across-pulsar-brokers) incoming messages from producers, dispatches messages to consumers, communicates with the Pulsar configuration store to handle various coordination tasks, stores messages in BookKeeper instances (aka bookies), relies on a cluster-specific ZooKeeper cluster for certain tasks, and more.
+* One or more brokers handles and [load balances](administration-load-balance.md) incoming messages from producers, dispatches messages to consumers, communicates with the Pulsar configuration store to handle various coordination tasks, stores messages in BookKeeper instances (aka bookies), relies on a cluster-specific ZooKeeper cluster for certain tasks, and more.
* A BookKeeper cluster consisting of one or more bookies handles [persistent storage](#persistent-storage) of messages.
* A ZooKeeper cluster specific to that cluster handles coordination tasks between Pulsar clusters.
diff --git a/site2/website-next/docs/reference-terminology.md b/site2/website-next/docs/reference-terminology.md
index ebc114d86f7..8a5e7914964 100644
--- a/site2/website-next/docs/reference-terminology.md
+++ b/site2/website-next/docs/reference-terminology.md
@@ -97,6 +97,15 @@ that have already been [acknowledged](#acknowledgement-ack).
The ability to isolate [namespaces](#namespace), specify quotas, and configure authentication and authorization
on a per-[tenant](#tenant) basis.
+#### Failure Domain
+
+A logical domain under a Pulsar cluster. Each logical domain contains a pre-configured list of brokers.
+
+#### Anti-affinity Namespaces
+
+A group of namespaces that have anti-affinity to each other.
+
+
### Architecture
#### Standalone
diff --git a/site2/website-next/static/assets/anti-affinity-namespaces-across-failure-domains.svg b/site2/website-next/static/assets/anti-affinity-namespaces-across-failure-domains.svg
new file mode 100644
index 00000000000..6abb48d1420
--- /dev/null
+++ b/site2/website-next/static/assets/anti-affinity-namespaces-across-failure-domains.svg
@@ -0,0 +1 @@
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diff --git a/site2/website-next/versioned_docs/version-2.10.0/administration-load-balance.md b/site2/website-next/versioned_docs/version-2.10.0/administration-load-balance.md
index 49e76e52995..3bb295d25cb 100644
--- a/site2/website-next/versioned_docs/version-2.10.0/administration-load-balance.md
+++ b/site2/website-next/versioned_docs/version-2.10.0/administration-load-balance.md
@@ -1,111 +1,82 @@
---
id: administration-load-balance
-title: Pulsar load balance
+title: Load balance across brokers
sidebar_label: "Load balance"
original_id: administration-load-balance
---
-## Load balance across Pulsar brokers
-Pulsar is an horizontally scalable messaging system, so the traffic in a logical cluster must be balanced across all the available Pulsar brokers as evenly as possible, which is a core requirement.
+Pulsar is a horizontally scalable messaging system, so the traffic in a logical cluster must be balanced across all the available Pulsar brokers as evenly as possible, which is a core requirement.
-You can use multiple settings and tools to control the traffic distribution which require a bit of context to understand how the traffic is managed in Pulsar. Though, in most cases, the core requirement mentioned above is true out of the box and you should not worry about it.
+You can use multiple settings and tools to control the traffic distribution which requires a bit of context to understand how the traffic is managed in Pulsar. Though in most cases, the core requirement mentioned above is true out of the box and you should not worry about it.
-## Pulsar load manager architecture
+The following sections introduce how the load-balanced assignments work across Pulsar brokers and how you can leverage the framework to adjust.
-The following part introduces the basic architecture of the Pulsar load manager.
+## Dynamic assignments
-### Assign topics to brokers dynamically
+Topics are dynamically assigned to brokers based on the load conditions of all brokers in the cluster. The assignment of topics to brokers is not done at the topic level but at the **bundle** level (a higher level). Instead of individual topic assignments, each broker takes ownership of a subset of the topics for a namespace. This subset is called a bundle and effectively this subset is a sharding mechanism.
-Topics are dynamically assigned to brokers based on the load conditions of all brokers in the cluster.
+In other words, each namespace is an "administrative" unit and sharded into a list of bundles, with each bundle comprising a portion of the overall hash range of the namespace. Topics are assigned to a particular bundle by taking the hash of the topic name and checking in which bundle the hash falls. Each bundle is independent of the others and thus is independently assigned to different brokers.
-When a client starts using new topics that are not assigned to any broker, a process is triggered to choose the best suited broker to acquire ownership of these topics according to the load conditions.
+The benefit of the assignment granularity is to amortize the amount of information that you need to keep track of. Based on CPU, memory, traffic load, and other indexes, topics are assigned to a particular broker dynamically. For example:
+* When a client starts using new topics that are not assigned to any broker, a process is triggered to choose the best-suited broker to acquire ownership of these topics according to the load conditions.
+* If the broker owning a topic becomes overloaded, the topic is reassigned to a less-loaded broker.
+* If the broker owning a topic crashes, the topic is reassigned to another active broker.
-In case of partitioned topics, different partitions are assigned to different brokers. Here "topic" means either a non-partitioned topic or one partition of a topic.
+:::tip
-The assignment is "dynamic" because the assignment changes quickly. For example, if the broker owning the topic crashes, the topic is reassigned immediately to another broker. Another scenario is that the broker owning the topic becomes overloaded. In this case, the topic is reassigned to a less loaded broker.
+For partitioned topics, different partitions are assigned to different brokers. Here "topic" means either a non-partitioned topic or one partition of a topic.
-The stateless nature of brokers makes the dynamic assignment possible, so you can quickly expand or shrink the cluster based on usage.
+:::
-#### Assignment granularity
+## Create namespaces with assigned bundles
-The assignment of topics or partitions to brokers is not done at the topics or partitions level, but done at the Bundle level (a higher level). The reason is to amortize the amount of information that you need to keep track. Based on CPU, memory, traffic load and other indexes, topics are assigned to a particular broker dynamically.
+When you create a new namespace, a number of bundles are assigned to the namespace. You can set this number in the `conf/broker.conf` file:
-Instead of individual topic or partition assignment, each broker takes ownership of a subset of the topics for a namespace. This subset is called a "*bundle*" and effectively this subset is a sharding mechanism.
+```conf
-The namespace is the "administrative" unit: many config knobs or operations are done at the namespace level.
-
-For assignment, a namespaces is sharded into a list of "bundles", with each bundle comprising a portion of overall hash range of the namespace.
-
-Topics are assigned to a particular bundle by taking the hash of the topic name and checking in which bundle the hash falls into.
-
-Each bundle is independent of the others and thus is independently assigned to different brokers.
-
-### Create namespaces and bundles
-
-When you create a new namespace, the new namespace sets to use the default number of bundles. You can set this in `conf/broker.conf`:
-
-```properties
-
-# When a namespace is created without specifying the number of bundle, this
+# When a namespace is created without specifying the number of bundles, this
# value will be used as the default
defaultNumberOfNamespaceBundles=4
```
-You can either change the system default, or override it when you create a new namespace:
+Alternatively, you can override the value when you create a new namespace using [Pulsar admin](/tools/pulsar-admin/):
```shell
-$ bin/pulsar-admin namespaces create my-tenant/my-namespace --clusters us-west --bundles 16
+bin/pulsar-admin namespaces create my-tenant/my-namespace --clusters us-west --bundles 16
```
-With this command, you create a namespace with 16 initial bundles. Therefore the topics for this namespaces can immediately be spread across up to 16 brokers.
+With the above command, you create a namespace with 16 initial bundles. Therefore the topics for this namespace can immediately be spread across up to 16 brokers.
In general, if you know the expected traffic and number of topics in advance, you had better start with a reasonable number of bundles instead of waiting for the system to auto-correct the distribution.
-On the same note, it is beneficial to start with more bundles than the number of brokers, because of the hashing nature of the distribution of topics into bundles. For example, for a namespace with 1000 topics, using something like 64 bundles achieves a good distribution of traffic across 16 brokers.
-
-### Unload topics and bundles
+On the same note, it is beneficial to start with more bundles than the number of brokers, due to the hashing nature of the distribution of topics into bundles. For example, for a namespace with 1000 topics, using something like 64 bundles achieves a good distribution of traffic across 16 brokers.
-You can "unload" a topic in Pulsar with admin operation. Unloading means to close the topics, release ownership and reassign the topics to a new broker, based on current load.
-When unloading happens, the client experiences a small latency blip, typically in the order of tens of milliseconds, while the topic is reassigned.
+## Split namespace bundles
-Unloading is the mechanism that the load-manager uses to perform the load shedding, but you can also trigger the unloading manually, for example to correct the assignments and redistribute traffic even before having any broker overloaded.
+Since the load for the topics in a bundle might change over time and predicting the load might be hard, bundle split is designed to resolve these challenges. The broker splits a bundle into two and the new smaller bundles can be reassigned to different brokers.
-Unloading a topic has no effect on the assignment, but just closes and reopens the particular topic:
+Pulsar supports the following two bundle split algorithms:
+* `range_equally_divide`: split the bundle into two parts with the same hash range size.
+* `topic_count_equally_divide`: split the bundle into two parts with the same number of topics.
-```shell
+To enable bundle split, you need to configure the following settings in the `broker.conf` file, and set `defaultNamespaceBundleSplitAlgorithm` based on your needs.
-pulsar-admin topics unload persistent://tenant/namespace/topic
+```conf
-```
-
-To unload all topics for a namespace and trigger reassignments:
-
-```shell
-
-pulsar-admin namespaces unload tenant/namespace
+loadBalancerAutoBundleSplitEnabled=true
+loadBalancerAutoUnloadSplitBundlesEnabled=true
+defaultNamespaceBundleSplitAlgorithm=range_equally_divide
```
-### Split namespace bundles
-
-Since the load for the topics in a bundle might change over time and predicting the load might be hard, bundle split is designed to deal with these issues. The broker splits a bundle into two and the new smaller bundles can be reassigned to different brokers.
-
-The splitting is based on some tunable thresholds. Any existing bundle that exceeds any of the threshold is a candidate to be split. By default the newly split bundles are also immediately offloaded to other brokers, to facilitate the traffic distribution.
+You can configure more parameters for splitting thresholds. Any existing bundle that exceeds any of the thresholds is a candidate to be split. By default, the newly split bundles are immediately reassigned to other brokers, to facilitate the traffic distribution.
-You can split namespace bundles in two ways, by setting `supportedNamespaceBundleSplitAlgorithms` to `range_equally_divide` or `topic_count_equally_divide` in `broker.conf` file. The former splits the bundle into two parts with the same hash range size; the latter splits the bundle into two parts with the same number of topics. You can also configure other parameters for namespace bundles.
-
-```properties
-
-# enable/disable namespace bundle auto split
-loadBalancerAutoBundleSplitEnabled=true
-
-# enable/disable automatic unloading of split bundles
-loadBalancerAutoUnloadSplitBundlesEnabled=true
+```conf
# maximum topics in a bundle, otherwise bundle split will be triggered
loadBalancerNamespaceBundleMaxTopics=1000
@@ -124,91 +95,184 @@ loadBalancerNamespaceMaximumBundles=128
```
-### Shed load automatically
+## Shed load automatically
-The support for automatic load shedding is available in the load manager of Pulsar. This means that whenever the system recognizes a particular broker is overloaded, the system forces some traffic to be reassigned to less loaded brokers.
+The support for automatic load shedding is available in the load manager of Pulsar. This means that whenever the system recognizes a particular broker is overloaded, the system forces some traffic to be reassigned to less-loaded brokers.
When a broker is identified as overloaded, the broker forces to "unload" a subset of the bundles, the ones with higher traffic, that make up for the overload percentage.
-For example, the default threshold is 85% and if a broker is over quota at 95% CPU usage, then the broker unloads the percent difference plus a 5% margin: `(95% - 85%) + 5% = 15%`.
-
-Given the selection of bundles to offload is based on traffic (as a proxy measure for cpu, network and memory), broker unloads bundles for at least 15% of traffic.
+For example, the default threshold is 85% and if a broker is over quota at 95% CPU usage, then the broker unloads the percent difference plus a 5% margin: `(95% - 85%) + 5% = 15%`. Given the selection of bundles to unload is based on traffic (as a proxy measure for CPU, network, and memory), the broker unloads bundles for at least 15% of traffic.
-The automatic load shedding is enabled by default and you can disable the automatic load shedding with this setting:
+:::tip
-```properties
+* The automatic load shedding is enabled by default. To disable it, you can set `loadBalancerSheddingEnabled` to `false`.
+* Besides the automatic load shedding, you can [manually unload bundles](#unload-topics-and-bundles).
-# Enable/disable automatic bundle unloading for load-shedding
-loadBalancerSheddingEnabled=true
-
-```
+:::
Additional settings that apply to shedding:
-```properties
+```conf
# Load shedding interval. Broker periodically checks whether some traffic should be offload from
# some over-loaded broker to other under-loaded brokers
loadBalancerSheddingIntervalMinutes=1
-# Prevent the same topics to be shed and moved to other brokers more that once within this timeframe
+# Prevent the same topics to be shed and moved to other brokers more than once within this timeframe
loadBalancerSheddingGracePeriodMinutes=30
```
-Pulsar supports the following types of shedding strategies. From Pulsar 2.10, the **default** shedding strategy is `ThresholdShedder`.
+Pulsar supports the following types of automatic load shedding strategies.
+* [ThresholdShedder](#thresholdshedder)
+* [OverloadShedder](#overloadshedder)
+* [UniformLoadShedder](#uniformloadshedder)
-##### ThresholdShedder
-This strategy tends to shed the bundles if any broker's usage is above the configured threshold. It does this by first computing the average resource usage per broker for the whole cluster. The resource usage for each broker is calculated using the following method: LocalBrokerData#getMaxResourceUsageWithWeight. The weights for each resource are configurable. Historical observations are included in the running average based on the broker's setting for loadBalancerHistoryResourcePercentag [...]
-`loadBalancerLoadSheddingStrategy=org.apache.pulsar.broker.loadbalance.impl.ThresholdShedder`
+:::note
+
+* From Pulsar 2.10, the **default** shedding strategy is `ThresholdShedder`.
+* You need to restart brokers if the shedding strategy is [dynamically updated](admin-api-brokers.md/#dynamic-broker-configuration).
+
+:::
+
+### ThresholdShedder
+This strategy tends to shed the bundles if any broker's usage is above the configured threshold. It does this by first computing the average resource usage per broker for the whole cluster. The resource usage for each broker is calculated using the following method `LocalBrokerData#getMaxResourceUsageWithWeight`. Historical observations are included in the running average based on the broker's setting for `loadBalancerHistoryResourcePercentage`. Once the average resource usage is calcula [...]
-##### OverloadShedder
-This strategy will attempt to shed exactly one bundle on brokers which are overloaded, that is, whose maximum system resource usage exceeds loadBalancerBrokerOverloadedThresholdPercentage. To see which resources are considered when determining the maximum system resource. A bundle is recommended for unloading off that broker if and only if the following conditions hold: The broker has at least two bundles assigned and the broker has at least one bundle that has not been unloaded recently [...]
-`loadBalancerLoadSheddingStrategy=org.apache.pulsar.broker.loadbalance.impl.OverloadShedder`
+To use the `ThresholdShedder` strategy, configure brokers with this value.
+`loadBalancerLoadSheddingStrategy=org.apache.pulsar.broker.loadbalance.impl.ThresholdShedder`
+
+You can configure the weights for each resource per broker in the `conf/broker.conf` file.
+
+```conf
+
+# The BandWithIn usage weight when calculating new resource usage.
+loadBalancerBandwithInResourceWeight=1.0
+
+# The BandWithOut usage weight when calculating new resource usage.
+loadBalancerBandwithOutResourceWeight=1.0
+
+# The CPU usage weight when calculating new resource usage.
+loadBalancerCPUResourceWeight=1.0
+
+# The heap memory usage weight when calculating new resource usage.
+loadBalancerMemoryResourceWeight=1.0
+
+# The direct memory usage weight when calculating new resource usage.
+loadBalancerDirectMemoryResourceWeight=1.0
+
+```
+
+### OverloadShedder
+This strategy attempts to shed exactly one bundle on brokers which are overloaded, that is, whose maximum system resource usage exceeds [`loadBalancerBrokerOverloadedThresholdPercentage`](#broker-overload-thresholds). To see which resources are considered when determining the maximum system resource. A bundle is recommended for unloading off that broker if and only if the following conditions hold: The broker has at least two bundles assigned and the broker has at least one bundle that h [...]
-##### UniformLoadShedder
-This strategy tends to distribute load uniformly across all brokers. This strategy checks laod difference between broker with highest load and broker with lowest load. If the difference is higher than configured thresholds `loadBalancerMsgRateDifferenceShedderThreshold` and `loadBalancerMsgThroughputMultiplierDifferenceShedderThreshold` then it finds out bundles which can be unloaded to distribute traffic evenly across all brokers. Configure broker with below value to use this strategy.
-`loadBalancerLoadSheddingStrategy=org.apache.pulsar.broker.loadbalance.impl.UniformLoadShedder`
+To use the `OverloadShedder` strategy, configure brokers with this value.
+`loadBalancerLoadSheddingStrategy=org.apache.pulsar.broker.loadbalance.impl.OverloadShedder`
+
+#### Broker overload thresholds
+
+The determination of when a broker is overloaded is based on the threshold of CPU, network, and memory usage. Whenever either of those metrics reaches the threshold, the system triggers the shedding (if enabled).
+
+:::note
+
+The overload threshold `loadBalancerBrokerOverloadedThresholdPercentage` only applies to the [`OverloadShedder`](#overloadshedder) shedding strategy. By default, it is set to 85%.
+
+:::
+
+Pulsar gathers the CPU, network, and memory usage stats from the system metrics. In some cases of network utilization, the network interface speed that Linux reports is not correct and needs to be manually overridden. This is the case in AWS EC2 instances with 1Gbps NIC speed for which the OS reports 10Gbps speed.
+
+Because of the incorrect max speed, the load manager might think the broker has not reached the NIC capacity, while in fact the broker already uses all the bandwidth and the traffic is slowed down.
+
+You can set `loadBalancerOverrideBrokerNicSpeedGbps` in the `conf/broker.conf` file to correct the max NIC speed. When the value is empty, Pulsar uses the value that the OS reports.
+
+### UniformLoadShedder
+This strategy tends to distribute load uniformly across all brokers. This strategy checks the load difference between the broker with the highest load and the broker with the lowest load. If the difference is higher than configured thresholds `loadBalancerMsgRateDifferenceShedderThreshold` and `loadBalancerMsgThroughputMultiplierDifferenceShedderThreshold` then it finds out bundles that can be unloaded to distribute traffic evenly across all brokers.
-#### Broker overload thresholds
+To use the `UniformLoadShedder` strategy, configure brokers with this value.
+`loadBalancerLoadSheddingStrategy=org.apache.pulsar.broker.loadbalance.impl.UniformLoadShedder`
+
+## Unload topics and bundles
+
+You can "unload" a topic in Pulsar manual admin operations. Unloading means closing topics, releasing ownership, and reassigning topics to a new broker, based on the current load.
+
+When unloading happens, the client experiences a small latency blip, typically in the order of tens of milliseconds, while the topic is reassigned.
+
+Unloading is the mechanism that the load manager uses to perform the load shedding, but you can also trigger the unloading manually, for example, to correct the assignments and redistribute traffic even before having any broker overloaded.
+
+Unloading a topic has no effect on the assignment, but just closes and reopens the particular topic:
-The determinations of when a broker is overloaded is based on threshold of CPU, network and memory usage. Whenever either of those metrics reaches the threshold, the system triggers the shedding (if enabled).
+```shell
-By default, overload threshold is set at 85%:
+pulsar-admin topics unload persistent://tenant/namespace/topic
-```properties
+```
-# Usage threshold to determine a broker as over-loaded
-loadBalancerBrokerOverloadedThresholdPercentage=85
+To unload all topics for a namespace and trigger reassignments:
+
+```shell
+
+pulsar-admin namespaces unload tenant/namespace
```
-Pulsar gathers the usage stats from the system metrics.
+## Distribute anti-affinity namespaces across failure domains
+
+When your application has multiple namespaces and you want one of them available all the time to avoid any downtime, you can group these namespaces and distribute them across different [failure domains](reference-terminology.md#failure-domain) and different brokers. Thus, if one of the failure domains is down (due to release rollout or brokers restart), it only disrupts namespaces owned by that specific failure domain and the rest of the namespaces owned by other domains remain available [...]
+
+Such a group of namespaces has anti-affinity to each other, that is, all the namespaces in this group are [anti-affinity namespaces](reference-terminology.md#anti-affinity-namespaces) and are distributed to different failure domains in a load-balanced manner.
-In case of network utilization, in some cases the network interface speed that Linux reports is not correct and needs to be manually overridden. This is the case in AWS EC2 instances with 1Gbps NIC speed for which the OS reports 10Gbps speed.
+As illustrated in the following figure, Pulsar has 2 failure domains (Domain1 and Domain2) and each domain has 2 brokers in it. You can create an anti-affinity namespace group that has 4 namespaces in it, and all the 4 namespaces have anti-affinity to each other. The load manager tries to distribute namespaces evenly across all the brokers in the same domain. Since each domain has 2 brokers, every broker owns one namespace from this anti-affinity namespace group, and you can see each dom [...]
-Because of the incorrect max speed, the Pulsar load manager might think the broker has not reached the NIC capacity, while in fact the broker already uses all the bandwidth and the traffic is slowed down.
+
-You can use the following setting to correct the max NIC speed:
+The load manager follows an even distribution policy across failure domains to assign anti-affinity namespaces. The following table outlines the even-distributed assignment sequence illustrated in the above figure.
-```properties
+| Assignment sequence | Namespace | Failure domain candidates | Broker candidates | Selected broker |
+|:---|:------------|:------------------|:------------------------------------|:-----------------|
+| 1 | Namespace1 | Domain1, Domain2 | Broker1, Broker2, Broker3, Broker4 | Domain1:Broker1 |
+| 2 | Namespace2 | Domain2 | Broker3, Broker4 | Domain2:Broker3 |
+| 3 | Namespace3 | Domain1, Domain2 | Broker2, Broker4 | Domain1:Broker2 |
+| 4 | Namespace4 | Domain2 | Broker4 | Domain2:Broker4 |
+
+:::tip
-# Override the auto-detection of the network interfaces max speed.
-# This option is useful in some environments (eg: EC2 VMs) where the max speed
-# reported by Linux is not reflecting the real bandwidth available to the broker.
-# Since the network usage is employed by the load manager to decide when a broker
-# is overloaded, it is important to make sure the info is correct or override it
-# with the right value here. The configured value can be a double (eg: 0.8) and that
-# can be used to trigger load-shedding even before hitting on NIC limits.
-loadBalancerOverrideBrokerNicSpeedGbps=
+* Each namespace belongs to only one anti-affinity group. If a namespace with an existing anti-affinity assignment is assigned to another anti-affinity group, the original assignment is dropped.
+
+* If there are more anti-affinity namespaces than failure domains, the load manager distributes namespaces evenly across all the domains, and also every domain distributes namespaces evenly across all the brokers under that domain.
+
+:::
+
+### Create a failure domain and register brokers
+
+:::note
+
+One broker can only be registered to a single failure domain.
+
+:::
+
+To create a domain under a specific cluster and register brokers, run the following command:
+
+```bash
+
+pulsar-admin clusters create-failure-domain <cluster-name> --domain-name <domain-name> --broker-list <broker-list-comma-separated>
```
-When the value is empty, Pulsar uses the value that the OS reports.
+You can also view, update, and delete domains under a specific cluster. For more information, refer to [Pulsar admin doc](/tools/pulsar-admin/).
+
+### Create an anti-affinity namespace group
+
+An anti-affinity group is created automatically when the first namespace is assigned to the group. To assign a namespace to an anti-affinity group, run the following command. It sets an anti-affinity group name for a namespace.
+
+```bash
+
+pulsar-admin namespaces set-anti-affinity-group <namespace> --group <group-name>
+
+```
+For more information about `anti-affinity-group` related commands, refer to [Pulsar admin doc](/tools/pulsar-admin/).
diff --git a/site2/website-next/versioned_docs/version-2.10.0/reference-terminology.md b/site2/website-next/versioned_docs/version-2.10.0/reference-terminology.md
index d0e736860e2..e5099141c32 100644
--- a/site2/website-next/versioned_docs/version-2.10.0/reference-terminology.md
+++ b/site2/website-next/versioned_docs/version-2.10.0/reference-terminology.md
@@ -98,6 +98,14 @@ that have already been [acknowledged](#acknowledgement-ack).
The ability to isolate [namespaces](#namespace), specify quotas, and configure authentication and authorization
on a per-[tenant](#tenant) basis.
+#### Failure Domain
+
+A logical domain under a Pulsar cluster. Each logical domain contains a pre-configured list of brokers.
+
+#### Anti-affinity Namespaces
+
+A group of namespaces that have anti-affinity to each other.
+
### Architecture
#### Standalone
diff --git a/site2/website-next/versioned_docs/version-2.8.0/administration-load-balance.md b/site2/website-next/versioned_docs/version-2.8.0/administration-load-balance.md
index 3efba601ed4..890ebf66162 100644
--- a/site2/website-next/versioned_docs/version-2.8.0/administration-load-balance.md
+++ b/site2/website-next/versioned_docs/version-2.8.0/administration-load-balance.md
@@ -198,3 +198,59 @@ loadBalancerOverrideBrokerNicSpeedGbps=
When the value is empty, Pulsar uses the value that the OS reports.
+### Distribute anti-affinity namespaces across failure domains
+
+When your application has multiple namespaces and you want one of them available all the time to avoid any downtime, you can group these namespaces and distribute them across different [failure domains](reference-terminology.md#failure-domain) and different brokers. Thus, if one of the failure domains is down (due to release rollout or brokers restart), it only disrupts namespaces owned by that specific failure domain and the rest of the namespaces owned by other domains remain available [...]
+
+Such a group of namespaces has anti-affinity to each other, that is, all the namespaces in this group are [anti-affinity namespaces](reference-terminology.md#anti-affinity-namespaces) and are distributed to different failure domains in a load-balanced manner.
+
+As illustrated in the following figure, Pulsar has 2 failure domains (Domain1 and Domain2) and each domain has 2 brokers in it. You can create an anti-affinity namespace group that has 4 namespaces in it, and all the 4 namespaces have anti-affinity to each other. The load manager tries to distribute namespaces evenly across all the brokers in the same domain. Since each domain has 2 brokers, every broker owns one namespace from this anti-affinity namespace group, and you can see each dom [...]
+
+
+
+The load manager follows an even distribution policy across failure domains to assign anti-affinity namespaces. The following table outlines the even-distributed assignment sequence illustrated in the above figure.
+
+| Assignment sequence | Namespace | Failure domain candidates | Broker candidates | Selected broker |
+|:---|:------------|:------------------|:------------------------------------|:-----------------|
+| 1 | Namespace1 | Domain1, Domain2 | Broker1, Broker2, Broker3, Broker4 | Domain1:Broker1 |
+| 2 | Namespace2 | Domain2 | Broker3, Broker4 | Domain2:Broker3 |
+| 3 | Namespace3 | Domain1, Domain2 | Broker2, Broker4 | Domain1:Broker2 |
+| 4 | Namespace4 | Domain2 | Broker4 | Domain2:Broker4 |
+
+:::tip
+
+* Each namespace belongs to only one anti-affinity group. If a namespace with an existing anti-affinity assignment is assigned to another anti-affinity group, the original assignment is dropped.
+
+* If there are more anti-affinity namespaces than failure domains, the load manager distributes namespaces evenly across all the domains, and also every domain distributes namespaces evenly across all the brokers under that domain.
+
+:::
+
+#### Create a failure domain and register brokers
+
+:::note
+
+One broker can only be registered to a single failure domain.
+
+:::
+
+To create a domain under a specific cluster and register brokers, run the following command:
+
+```bash
+
+pulsar-admin clusters create-failure-domain <cluster-name> --domain-name <domain-name> --broker-list <broker-list-comma-separated>
+
+```
+
+You can also view, update, and delete domains under a specific cluster. For more information, refer to [Pulsar admin doc](/tools/pulsar-admin/).
+
+#### Create an anti-affinity namespace group
+
+An anti-affinity group is created automatically when the first namespace is assigned to the group. To assign a namespace to an anti-affinity group, run the following command. It sets an anti-affinity group name for a namespace.
+
+```bash
+
+pulsar-admin namespaces set-anti-affinity-group <namespace> --group <group-name>
+
+```
+
+For more information about `anti-affinity-group` related commands, refer to [Pulsar admin doc](/tools/pulsar-admin/).
diff --git a/site2/website-next/versioned_docs/version-2.8.0/reference-terminology.md b/site2/website-next/versioned_docs/version-2.8.0/reference-terminology.md
index d0e736860e2..e5099141c32 100644
--- a/site2/website-next/versioned_docs/version-2.8.0/reference-terminology.md
+++ b/site2/website-next/versioned_docs/version-2.8.0/reference-terminology.md
@@ -98,6 +98,14 @@ that have already been [acknowledged](#acknowledgement-ack).
The ability to isolate [namespaces](#namespace), specify quotas, and configure authentication and authorization
on a per-[tenant](#tenant) basis.
+#### Failure Domain
+
+A logical domain under a Pulsar cluster. Each logical domain contains a pre-configured list of brokers.
+
+#### Anti-affinity Namespaces
+
+A group of namespaces that have anti-affinity to each other.
+
### Architecture
#### Standalone
diff --git a/site2/website-next/versioned_docs/version-2.8.1/administration-load-balance.md b/site2/website-next/versioned_docs/version-2.8.1/administration-load-balance.md
index 3efba601ed4..134c39e0956 100644
--- a/site2/website-next/versioned_docs/version-2.8.1/administration-load-balance.md
+++ b/site2/website-next/versioned_docs/version-2.8.1/administration-load-balance.md
@@ -198,3 +198,59 @@ loadBalancerOverrideBrokerNicSpeedGbps=
When the value is empty, Pulsar uses the value that the OS reports.
+### Distribute anti-affinity namespaces across failure domains
+
+When your application has multiple namespaces and you want one of them available all the time to avoid any downtime, you can group these namespaces and distribute them across different [failure domains](reference-terminology.md#failure-domain) and different brokers. Thus, if one of the failure domains is down (due to release rollout or brokers restart), it only disrupts namespaces owned by that specific failure domain and the rest of the namespaces owned by other domains remain available [...]
+
+Such a group of namespaces has anti-affinity to each other, that is, all the namespaces in this group are [anti-affinity namespaces](reference-terminology.md#anti-affinity-namespaces) and are distributed to different failure domains in a load-balanced manner.
+
+As illustrated in the following figure, Pulsar has 2 failure domains (Domain1 and Domain2) and each domain has 2 brokers in it. You can create an anti-affinity namespace group that has 4 namespaces in it, and all the 4 namespaces have anti-affinity to each other. The load manager tries to distribute namespaces evenly across all the brokers in the same domain. Since each domain has 2 brokers, every broker owns one namespace from this anti-affinity namespace group, and you can see each dom [...]
+
+
+
+The load manager follows an even distribution policy across failure domains to assign anti-affinity namespaces. The following table outlines the even-distributed assignment sequence illustrated in the above figure.
+
+| Assignment sequence | Namespace | Failure domain candidates | Broker candidates | Selected broker |
+|:---|:------------|:------------------|:------------------------------------|:-----------------|
+| 1 | Namespace1 | Domain1, Domain2 | Broker1, Broker2, Broker3, Broker4 | Domain1:Broker1 |
+| 2 | Namespace2 | Domain2 | Broker3, Broker4 | Domain2:Broker3 |
+| 3 | Namespace3 | Domain1, Domain2 | Broker2, Broker4 | Domain1:Broker2 |
+| 4 | Namespace4 | Domain2 | Broker4 | Domain2:Broker4 |
+
+:::tip
+
+* Each namespace belongs to only one anti-affinity group. If a namespace with an existing anti-affinity assignment is assigned to another anti-affinity group, the original assignment is dropped.
+
+* If there are more anti-affinity namespaces than failure domains, the load manager distributes namespaces evenly across all the domains, and also every domain distributes namespaces evenly across all the brokers under that domain.
+
+:::
+
+#### Create a failure domain and register brokers
+
+:::note
+
+One broker can only be registered to a single failure domain.
+
+:::
+
+To create a domain under a specific cluster and register brokers, run the following command:
+
+```bash
+
+pulsar-admin clusters create-failure-domain <cluster-name> --domain-name <domain-name> --broker-list <broker-list-comma-separated>
+
+```
+
+You can also view, update, and delete domains under a specific cluster. For more information, refer to [Pulsar admin doc](/tools/pulsar-admin/).
+
+#### Create an anti-affinity namespace group
+
+An anti-affinity group is created automatically when the first namespace is assigned to the group. To assign a namespace to an anti-affinity group, run the following command. It sets an anti-affinity group name for a namespace.
+
+```bash
+
+pulsar-admin namespaces set-anti-affinity-group <namespace> --group <group-name>
+
+```
+
+For more information about `anti-affinity-group` related commands, refer to [Pulsar admin doc](/tools/pulsar-admin/).
\ No newline at end of file
diff --git a/site2/website-next/versioned_docs/version-2.8.1/reference-terminology.md b/site2/website-next/versioned_docs/version-2.8.1/reference-terminology.md
index d0e736860e2..e5099141c32 100644
--- a/site2/website-next/versioned_docs/version-2.8.1/reference-terminology.md
+++ b/site2/website-next/versioned_docs/version-2.8.1/reference-terminology.md
@@ -98,6 +98,14 @@ that have already been [acknowledged](#acknowledgement-ack).
The ability to isolate [namespaces](#namespace), specify quotas, and configure authentication and authorization
on a per-[tenant](#tenant) basis.
+#### Failure Domain
+
+A logical domain under a Pulsar cluster. Each logical domain contains a pre-configured list of brokers.
+
+#### Anti-affinity Namespaces
+
+A group of namespaces that have anti-affinity to each other.
+
### Architecture
#### Standalone
diff --git a/site2/website-next/versioned_docs/version-2.8.2/administration-load-balance.md b/site2/website-next/versioned_docs/version-2.8.2/administration-load-balance.md
index 3efba601ed4..134c39e0956 100644
--- a/site2/website-next/versioned_docs/version-2.8.2/administration-load-balance.md
+++ b/site2/website-next/versioned_docs/version-2.8.2/administration-load-balance.md
@@ -198,3 +198,59 @@ loadBalancerOverrideBrokerNicSpeedGbps=
When the value is empty, Pulsar uses the value that the OS reports.
+### Distribute anti-affinity namespaces across failure domains
+
+When your application has multiple namespaces and you want one of them available all the time to avoid any downtime, you can group these namespaces and distribute them across different [failure domains](reference-terminology.md#failure-domain) and different brokers. Thus, if one of the failure domains is down (due to release rollout or brokers restart), it only disrupts namespaces owned by that specific failure domain and the rest of the namespaces owned by other domains remain available [...]
+
+Such a group of namespaces has anti-affinity to each other, that is, all the namespaces in this group are [anti-affinity namespaces](reference-terminology.md#anti-affinity-namespaces) and are distributed to different failure domains in a load-balanced manner.
+
+As illustrated in the following figure, Pulsar has 2 failure domains (Domain1 and Domain2) and each domain has 2 brokers in it. You can create an anti-affinity namespace group that has 4 namespaces in it, and all the 4 namespaces have anti-affinity to each other. The load manager tries to distribute namespaces evenly across all the brokers in the same domain. Since each domain has 2 brokers, every broker owns one namespace from this anti-affinity namespace group, and you can see each dom [...]
+
+
+
+The load manager follows an even distribution policy across failure domains to assign anti-affinity namespaces. The following table outlines the even-distributed assignment sequence illustrated in the above figure.
+
+| Assignment sequence | Namespace | Failure domain candidates | Broker candidates | Selected broker |
+|:---|:------------|:------------------|:------------------------------------|:-----------------|
+| 1 | Namespace1 | Domain1, Domain2 | Broker1, Broker2, Broker3, Broker4 | Domain1:Broker1 |
+| 2 | Namespace2 | Domain2 | Broker3, Broker4 | Domain2:Broker3 |
+| 3 | Namespace3 | Domain1, Domain2 | Broker2, Broker4 | Domain1:Broker2 |
+| 4 | Namespace4 | Domain2 | Broker4 | Domain2:Broker4 |
+
+:::tip
+
+* Each namespace belongs to only one anti-affinity group. If a namespace with an existing anti-affinity assignment is assigned to another anti-affinity group, the original assignment is dropped.
+
+* If there are more anti-affinity namespaces than failure domains, the load manager distributes namespaces evenly across all the domains, and also every domain distributes namespaces evenly across all the brokers under that domain.
+
+:::
+
+#### Create a failure domain and register brokers
+
+:::note
+
+One broker can only be registered to a single failure domain.
+
+:::
+
+To create a domain under a specific cluster and register brokers, run the following command:
+
+```bash
+
+pulsar-admin clusters create-failure-domain <cluster-name> --domain-name <domain-name> --broker-list <broker-list-comma-separated>
+
+```
+
+You can also view, update, and delete domains under a specific cluster. For more information, refer to [Pulsar admin doc](/tools/pulsar-admin/).
+
+#### Create an anti-affinity namespace group
+
+An anti-affinity group is created automatically when the first namespace is assigned to the group. To assign a namespace to an anti-affinity group, run the following command. It sets an anti-affinity group name for a namespace.
+
+```bash
+
+pulsar-admin namespaces set-anti-affinity-group <namespace> --group <group-name>
+
+```
+
+For more information about `anti-affinity-group` related commands, refer to [Pulsar admin doc](/tools/pulsar-admin/).
\ No newline at end of file
diff --git a/site2/website-next/versioned_docs/version-2.8.2/reference-terminology.md b/site2/website-next/versioned_docs/version-2.8.2/reference-terminology.md
index d0e736860e2..e5099141c32 100644
--- a/site2/website-next/versioned_docs/version-2.8.2/reference-terminology.md
+++ b/site2/website-next/versioned_docs/version-2.8.2/reference-terminology.md
@@ -98,6 +98,14 @@ that have already been [acknowledged](#acknowledgement-ack).
The ability to isolate [namespaces](#namespace), specify quotas, and configure authentication and authorization
on a per-[tenant](#tenant) basis.
+#### Failure Domain
+
+A logical domain under a Pulsar cluster. Each logical domain contains a pre-configured list of brokers.
+
+#### Anti-affinity Namespaces
+
+A group of namespaces that have anti-affinity to each other.
+
### Architecture
#### Standalone
diff --git a/site2/website-next/versioned_docs/version-2.8.3/administration-load-balance.md b/site2/website-next/versioned_docs/version-2.8.3/administration-load-balance.md
index 3efba601ed4..134c39e0956 100644
--- a/site2/website-next/versioned_docs/version-2.8.3/administration-load-balance.md
+++ b/site2/website-next/versioned_docs/version-2.8.3/administration-load-balance.md
@@ -198,3 +198,59 @@ loadBalancerOverrideBrokerNicSpeedGbps=
When the value is empty, Pulsar uses the value that the OS reports.
+### Distribute anti-affinity namespaces across failure domains
+
+When your application has multiple namespaces and you want one of them available all the time to avoid any downtime, you can group these namespaces and distribute them across different [failure domains](reference-terminology.md#failure-domain) and different brokers. Thus, if one of the failure domains is down (due to release rollout or brokers restart), it only disrupts namespaces owned by that specific failure domain and the rest of the namespaces owned by other domains remain available [...]
+
+Such a group of namespaces has anti-affinity to each other, that is, all the namespaces in this group are [anti-affinity namespaces](reference-terminology.md#anti-affinity-namespaces) and are distributed to different failure domains in a load-balanced manner.
+
+As illustrated in the following figure, Pulsar has 2 failure domains (Domain1 and Domain2) and each domain has 2 brokers in it. You can create an anti-affinity namespace group that has 4 namespaces in it, and all the 4 namespaces have anti-affinity to each other. The load manager tries to distribute namespaces evenly across all the brokers in the same domain. Since each domain has 2 brokers, every broker owns one namespace from this anti-affinity namespace group, and you can see each dom [...]
+
+
+
+The load manager follows an even distribution policy across failure domains to assign anti-affinity namespaces. The following table outlines the even-distributed assignment sequence illustrated in the above figure.
+
+| Assignment sequence | Namespace | Failure domain candidates | Broker candidates | Selected broker |
+|:---|:------------|:------------------|:------------------------------------|:-----------------|
+| 1 | Namespace1 | Domain1, Domain2 | Broker1, Broker2, Broker3, Broker4 | Domain1:Broker1 |
+| 2 | Namespace2 | Domain2 | Broker3, Broker4 | Domain2:Broker3 |
+| 3 | Namespace3 | Domain1, Domain2 | Broker2, Broker4 | Domain1:Broker2 |
+| 4 | Namespace4 | Domain2 | Broker4 | Domain2:Broker4 |
+
+:::tip
+
+* Each namespace belongs to only one anti-affinity group. If a namespace with an existing anti-affinity assignment is assigned to another anti-affinity group, the original assignment is dropped.
+
+* If there are more anti-affinity namespaces than failure domains, the load manager distributes namespaces evenly across all the domains, and also every domain distributes namespaces evenly across all the brokers under that domain.
+
+:::
+
+#### Create a failure domain and register brokers
+
+:::note
+
+One broker can only be registered to a single failure domain.
+
+:::
+
+To create a domain under a specific cluster and register brokers, run the following command:
+
+```bash
+
+pulsar-admin clusters create-failure-domain <cluster-name> --domain-name <domain-name> --broker-list <broker-list-comma-separated>
+
+```
+
+You can also view, update, and delete domains under a specific cluster. For more information, refer to [Pulsar admin doc](/tools/pulsar-admin/).
+
+#### Create an anti-affinity namespace group
+
+An anti-affinity group is created automatically when the first namespace is assigned to the group. To assign a namespace to an anti-affinity group, run the following command. It sets an anti-affinity group name for a namespace.
+
+```bash
+
+pulsar-admin namespaces set-anti-affinity-group <namespace> --group <group-name>
+
+```
+
+For more information about `anti-affinity-group` related commands, refer to [Pulsar admin doc](/tools/pulsar-admin/).
\ No newline at end of file
diff --git a/site2/website-next/versioned_docs/version-2.8.3/reference-terminology.md b/site2/website-next/versioned_docs/version-2.8.3/reference-terminology.md
index d0e736860e2..e5099141c32 100644
--- a/site2/website-next/versioned_docs/version-2.8.3/reference-terminology.md
+++ b/site2/website-next/versioned_docs/version-2.8.3/reference-terminology.md
@@ -98,6 +98,14 @@ that have already been [acknowledged](#acknowledgement-ack).
The ability to isolate [namespaces](#namespace), specify quotas, and configure authentication and authorization
on a per-[tenant](#tenant) basis.
+#### Failure Domain
+
+A logical domain under a Pulsar cluster. Each logical domain contains a pre-configured list of brokers.
+
+#### Anti-affinity Namespaces
+
+A group of namespaces that have anti-affinity to each other.
+
### Architecture
#### Standalone
diff --git a/site2/website-next/versioned_docs/version-2.9.0/administration-load-balance.md b/site2/website-next/versioned_docs/version-2.9.0/administration-load-balance.md
index 2b2ac839581..788c84a5931 100644
--- a/site2/website-next/versioned_docs/version-2.9.0/administration-load-balance.md
+++ b/site2/website-next/versioned_docs/version-2.9.0/administration-load-balance.md
@@ -192,3 +192,59 @@ loadBalancerOverrideBrokerNicSpeedGbps=
When the value is empty, Pulsar uses the value that the OS reports.
+### Distribute anti-affinity namespaces across failure domains
+
+When your application has multiple namespaces and you want one of them available all the time to avoid any downtime, you can group these namespaces and distribute them across different [failure domains](reference-terminology.md#failure-domain) and different brokers. Thus, if one of the failure domains is down (due to release rollout or brokers restart), it only disrupts namespaces owned by that specific failure domain and the rest of the namespaces owned by other domains remain available [...]
+
+Such a group of namespaces has anti-affinity to each other, that is, all the namespaces in this group are [anti-affinity namespaces](reference-terminology.md#anti-affinity-namespaces) and are distributed to different failure domains in a load-balanced manner.
+
+As illustrated in the following figure, Pulsar has 2 failure domains (Domain1 and Domain2) and each domain has 2 brokers in it. You can create an anti-affinity namespace group that has 4 namespaces in it, and all the 4 namespaces have anti-affinity to each other. The load manager tries to distribute namespaces evenly across all the brokers in the same domain. Since each domain has 2 brokers, every broker owns one namespace from this anti-affinity namespace group, and you can see each dom [...]
+
+
+
+The load manager follows an even distribution policy across failure domains to assign anti-affinity namespaces. The following table outlines the even-distributed assignment sequence illustrated in the above figure.
+
+| Assignment sequence | Namespace | Failure domain candidates | Broker candidates | Selected broker |
+|:---|:------------|:------------------|:------------------------------------|:-----------------|
+| 1 | Namespace1 | Domain1, Domain2 | Broker1, Broker2, Broker3, Broker4 | Domain1:Broker1 |
+| 2 | Namespace2 | Domain2 | Broker3, Broker4 | Domain2:Broker3 |
+| 3 | Namespace3 | Domain1, Domain2 | Broker2, Broker4 | Domain1:Broker2 |
+| 4 | Namespace4 | Domain2 | Broker4 | Domain2:Broker4 |
+
+:::tip
+
+* Each namespace belongs to only one anti-affinity group. If a namespace with an existing anti-affinity assignment is assigned to another anti-affinity group, the original assignment is dropped.
+
+* If there are more anti-affinity namespaces than failure domains, the load manager distributes namespaces evenly across all the domains, and also every domain distributes namespaces evenly across all the brokers under that domain.
+
+:::
+
+#### Create a failure domain and register brokers
+
+:::note
+
+One broker can only be registered to a single failure domain.
+
+:::
+
+To create a domain under a specific cluster and register brokers, run the following command:
+
+```bash
+
+pulsar-admin clusters create-failure-domain <cluster-name> --domain-name <domain-name> --broker-list <broker-list-comma-separated>
+
+```
+
+You can also view, update, and delete domains under a specific cluster. For more information, refer to [Pulsar admin doc](/tools/pulsar-admin/).
+
+#### Create an anti-affinity namespace group
+
+An anti-affinity group is created automatically when the first namespace is assigned to the group. To assign a namespace to an anti-affinity group, run the following command. It sets an anti-affinity group name for a namespace.
+
+```bash
+
+pulsar-admin namespaces set-anti-affinity-group <namespace> --group <group-name>
+
+```
+
+For more information about `anti-affinity-group` related commands, refer to [Pulsar admin doc](/tools/pulsar-admin/).
\ No newline at end of file
diff --git a/site2/website-next/versioned_docs/version-2.9.0/reference-terminology.md b/site2/website-next/versioned_docs/version-2.9.0/reference-terminology.md
index d0e736860e2..e5099141c32 100644
--- a/site2/website-next/versioned_docs/version-2.9.0/reference-terminology.md
+++ b/site2/website-next/versioned_docs/version-2.9.0/reference-terminology.md
@@ -98,6 +98,14 @@ that have already been [acknowledged](#acknowledgement-ack).
The ability to isolate [namespaces](#namespace), specify quotas, and configure authentication and authorization
on a per-[tenant](#tenant) basis.
+#### Failure Domain
+
+A logical domain under a Pulsar cluster. Each logical domain contains a pre-configured list of brokers.
+
+#### Anti-affinity Namespaces
+
+A group of namespaces that have anti-affinity to each other.
+
### Architecture
#### Standalone
diff --git a/site2/website-next/versioned_docs/version-2.9.1/administration-load-balance.md b/site2/website-next/versioned_docs/version-2.9.1/administration-load-balance.md
index 2b2ac839581..788c84a5931 100644
--- a/site2/website-next/versioned_docs/version-2.9.1/administration-load-balance.md
+++ b/site2/website-next/versioned_docs/version-2.9.1/administration-load-balance.md
@@ -192,3 +192,59 @@ loadBalancerOverrideBrokerNicSpeedGbps=
When the value is empty, Pulsar uses the value that the OS reports.
+### Distribute anti-affinity namespaces across failure domains
+
+When your application has multiple namespaces and you want one of them available all the time to avoid any downtime, you can group these namespaces and distribute them across different [failure domains](reference-terminology.md#failure-domain) and different brokers. Thus, if one of the failure domains is down (due to release rollout or brokers restart), it only disrupts namespaces owned by that specific failure domain and the rest of the namespaces owned by other domains remain available [...]
+
+Such a group of namespaces has anti-affinity to each other, that is, all the namespaces in this group are [anti-affinity namespaces](reference-terminology.md#anti-affinity-namespaces) and are distributed to different failure domains in a load-balanced manner.
+
+As illustrated in the following figure, Pulsar has 2 failure domains (Domain1 and Domain2) and each domain has 2 brokers in it. You can create an anti-affinity namespace group that has 4 namespaces in it, and all the 4 namespaces have anti-affinity to each other. The load manager tries to distribute namespaces evenly across all the brokers in the same domain. Since each domain has 2 brokers, every broker owns one namespace from this anti-affinity namespace group, and you can see each dom [...]
+
+
+
+The load manager follows an even distribution policy across failure domains to assign anti-affinity namespaces. The following table outlines the even-distributed assignment sequence illustrated in the above figure.
+
+| Assignment sequence | Namespace | Failure domain candidates | Broker candidates | Selected broker |
+|:---|:------------|:------------------|:------------------------------------|:-----------------|
+| 1 | Namespace1 | Domain1, Domain2 | Broker1, Broker2, Broker3, Broker4 | Domain1:Broker1 |
+| 2 | Namespace2 | Domain2 | Broker3, Broker4 | Domain2:Broker3 |
+| 3 | Namespace3 | Domain1, Domain2 | Broker2, Broker4 | Domain1:Broker2 |
+| 4 | Namespace4 | Domain2 | Broker4 | Domain2:Broker4 |
+
+:::tip
+
+* Each namespace belongs to only one anti-affinity group. If a namespace with an existing anti-affinity assignment is assigned to another anti-affinity group, the original assignment is dropped.
+
+* If there are more anti-affinity namespaces than failure domains, the load manager distributes namespaces evenly across all the domains, and also every domain distributes namespaces evenly across all the brokers under that domain.
+
+:::
+
+#### Create a failure domain and register brokers
+
+:::note
+
+One broker can only be registered to a single failure domain.
+
+:::
+
+To create a domain under a specific cluster and register brokers, run the following command:
+
+```bash
+
+pulsar-admin clusters create-failure-domain <cluster-name> --domain-name <domain-name> --broker-list <broker-list-comma-separated>
+
+```
+
+You can also view, update, and delete domains under a specific cluster. For more information, refer to [Pulsar admin doc](/tools/pulsar-admin/).
+
+#### Create an anti-affinity namespace group
+
+An anti-affinity group is created automatically when the first namespace is assigned to the group. To assign a namespace to an anti-affinity group, run the following command. It sets an anti-affinity group name for a namespace.
+
+```bash
+
+pulsar-admin namespaces set-anti-affinity-group <namespace> --group <group-name>
+
+```
+
+For more information about `anti-affinity-group` related commands, refer to [Pulsar admin doc](/tools/pulsar-admin/).
\ No newline at end of file
diff --git a/site2/website-next/versioned_docs/version-2.9.1/reference-terminology.md b/site2/website-next/versioned_docs/version-2.9.1/reference-terminology.md
index d0e736860e2..e5099141c32 100644
--- a/site2/website-next/versioned_docs/version-2.9.1/reference-terminology.md
+++ b/site2/website-next/versioned_docs/version-2.9.1/reference-terminology.md
@@ -98,6 +98,14 @@ that have already been [acknowledged](#acknowledgement-ack).
The ability to isolate [namespaces](#namespace), specify quotas, and configure authentication and authorization
on a per-[tenant](#tenant) basis.
+#### Failure Domain
+
+A logical domain under a Pulsar cluster. Each logical domain contains a pre-configured list of brokers.
+
+#### Anti-affinity Namespaces
+
+A group of namespaces that have anti-affinity to each other.
+
### Architecture
#### Standalone
diff --git a/site2/website-next/versioned_docs/version-2.9.2/administration-load-balance.md b/site2/website-next/versioned_docs/version-2.9.2/administration-load-balance.md
index 2b2ac839581..788c84a5931 100644
--- a/site2/website-next/versioned_docs/version-2.9.2/administration-load-balance.md
+++ b/site2/website-next/versioned_docs/version-2.9.2/administration-load-balance.md
@@ -192,3 +192,59 @@ loadBalancerOverrideBrokerNicSpeedGbps=
When the value is empty, Pulsar uses the value that the OS reports.
+### Distribute anti-affinity namespaces across failure domains
+
+When your application has multiple namespaces and you want one of them available all the time to avoid any downtime, you can group these namespaces and distribute them across different [failure domains](reference-terminology.md#failure-domain) and different brokers. Thus, if one of the failure domains is down (due to release rollout or brokers restart), it only disrupts namespaces owned by that specific failure domain and the rest of the namespaces owned by other domains remain available [...]
+
+Such a group of namespaces has anti-affinity to each other, that is, all the namespaces in this group are [anti-affinity namespaces](reference-terminology.md#anti-affinity-namespaces) and are distributed to different failure domains in a load-balanced manner.
+
+As illustrated in the following figure, Pulsar has 2 failure domains (Domain1 and Domain2) and each domain has 2 brokers in it. You can create an anti-affinity namespace group that has 4 namespaces in it, and all the 4 namespaces have anti-affinity to each other. The load manager tries to distribute namespaces evenly across all the brokers in the same domain. Since each domain has 2 brokers, every broker owns one namespace from this anti-affinity namespace group, and you can see each dom [...]
+
+
+
+The load manager follows an even distribution policy across failure domains to assign anti-affinity namespaces. The following table outlines the even-distributed assignment sequence illustrated in the above figure.
+
+| Assignment sequence | Namespace | Failure domain candidates | Broker candidates | Selected broker |
+|:---|:------------|:------------------|:------------------------------------|:-----------------|
+| 1 | Namespace1 | Domain1, Domain2 | Broker1, Broker2, Broker3, Broker4 | Domain1:Broker1 |
+| 2 | Namespace2 | Domain2 | Broker3, Broker4 | Domain2:Broker3 |
+| 3 | Namespace3 | Domain1, Domain2 | Broker2, Broker4 | Domain1:Broker2 |
+| 4 | Namespace4 | Domain2 | Broker4 | Domain2:Broker4 |
+
+:::tip
+
+* Each namespace belongs to only one anti-affinity group. If a namespace with an existing anti-affinity assignment is assigned to another anti-affinity group, the original assignment is dropped.
+
+* If there are more anti-affinity namespaces than failure domains, the load manager distributes namespaces evenly across all the domains, and also every domain distributes namespaces evenly across all the brokers under that domain.
+
+:::
+
+#### Create a failure domain and register brokers
+
+:::note
+
+One broker can only be registered to a single failure domain.
+
+:::
+
+To create a domain under a specific cluster and register brokers, run the following command:
+
+```bash
+
+pulsar-admin clusters create-failure-domain <cluster-name> --domain-name <domain-name> --broker-list <broker-list-comma-separated>
+
+```
+
+You can also view, update, and delete domains under a specific cluster. For more information, refer to [Pulsar admin doc](/tools/pulsar-admin/).
+
+#### Create an anti-affinity namespace group
+
+An anti-affinity group is created automatically when the first namespace is assigned to the group. To assign a namespace to an anti-affinity group, run the following command. It sets an anti-affinity group name for a namespace.
+
+```bash
+
+pulsar-admin namespaces set-anti-affinity-group <namespace> --group <group-name>
+
+```
+
+For more information about `anti-affinity-group` related commands, refer to [Pulsar admin doc](/tools/pulsar-admin/).
\ No newline at end of file
diff --git a/site2/website-next/versioned_docs/version-2.9.2/reference-terminology.md b/site2/website-next/versioned_docs/version-2.9.2/reference-terminology.md
index d0e736860e2..e5099141c32 100644
--- a/site2/website-next/versioned_docs/version-2.9.2/reference-terminology.md
+++ b/site2/website-next/versioned_docs/version-2.9.2/reference-terminology.md
@@ -98,6 +98,14 @@ that have already been [acknowledged](#acknowledgement-ack).
The ability to isolate [namespaces](#namespace), specify quotas, and configure authentication and authorization
on a per-[tenant](#tenant) basis.
+#### Failure Domain
+
+A logical domain under a Pulsar cluster. Each logical domain contains a pre-configured list of brokers.
+
+#### Anti-affinity Namespaces
+
+A group of namespaces that have anti-affinity to each other.
+
### Architecture
#### Standalone