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Posted to commits@helix.apache.org by ki...@apache.org on 2013/09/03 18:43:56 UTC
svn commit: r1519752 [2/46] - in /incubator/helix/site-content: ./
apidocs/assets/ apidocs/reference/ apidocs/reference/org/apache/helix/
apidocs/reference/org/apache/helix/agent/
apidocs/reference/org/apache/helix/alerts/ apidocs/reference/org/apache/...
Modified: incubator/helix/site-content/Architecture.html
URL: http://svn.apache.org/viewvc/incubator/helix/site-content/Architecture.html?rev=1519752&r1=1519751&r2=1519752&view=diff
==============================================================================
--- incubator/helix/site-content/Architecture.html (original)
+++ incubator/helix/site-content/Architecture.html Tue Sep 3 16:43:37 2013
@@ -1,13 +1,13 @@
<!DOCTYPE html>
<!--
- | Generated by Apache Maven Doxia at Aug 28, 2013
+ | Generated by Apache Maven Doxia at Sep 3, 2013
| Rendered using Apache Maven Fluido Skin 1.3.0
-->
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
- <meta name="Date-Revision-yyyymmdd" content="20130828" />
+ <meta name="Date-Revision-yyyymmdd" content="20130903" />
<meta http-equiv="Content-Language" content="en" />
<title>Apache Helix - </title>
<link rel="stylesheet" href="./css/apache-maven-fluido-1.3.0.min.css" />
@@ -86,6 +86,9 @@
<li> <a href="recipes/task_dag_execution.html" title="Distributed task DAG Execution">Distributed task DAG Execution</a>
</li>
+
+ <li> <a href="recipes/user_def_rebalancer.html" title="User-Defined Rebalancer Example">User-Defined Rebalancer Example</a>
+</li>
</ul>
</li>
<li class="dropdown">
@@ -168,7 +171,7 @@
- <li id="publishDate" class="pull-right">Last Published: 2013-08-28</li>
+ <li id="publishDate" class="pull-right">Last Published: 2013-09-03</li>
</ul>
</div>
@@ -203,32 +206,32 @@ under the License. --><p>Helix aims to p
<li>Manages entire operational lifecycle of a node. Addition, start, stop, enable/disable without downtime.</li>
<li>Monitor cluster health and provide alerts on SLA violation.</li>
<li>Service discovery mechanism to route requests.</li>
-</ul><p>To build such a system, we need a mechanism to co-ordinate between different nodes/components in the system. This mechanism can be achieved with a software that reacts to any change in the cluster and comes up with a set of tasks needed to bring the cluster to a stable state. The set of tasks will be assigned to one or more nodes in the cluster. Helix serves this purpose of managing the various components in the cluster.</p><p><img src="images/system.png" alt="Helix Design" /></p><p>Distributed System Components</p><p>In general any distributed system cluster will have the following</p>
+</ul><p>To build such a system, we need a mechanism to co-ordinate between different nodes and other components in the system. This mechanism can be achieved with software that reacts to any change in the cluster and comes up with a set of tasks needed to bring the cluster to a stable state. The set of tasks will be assigned to one or more nodes in the cluster. Helix serves this purpose of managing the various components in the cluster.</p><p><img src="images/system.png" alt="Helix Design" /></p><p>Distributed System Components</p><p>In general any distributed system cluster will have the following components and properties:</p>
<ul>
- <li>Set of nodes also referred to as an instance.</li>
- <li>Set of resources which can be a database, lucene index or a task.</li>
+ <li>A set of nodes also referred to as instances.</li>
+ <li>A set of resources which can be databases, lucene indexes or tasks.</li>
<li>Each resource is also partitioned into one or more Partitions.</li>
<li>Each partition may have one or more copies called replicas.</li>
<li>Each replica can have a state associated with it. For example Master, Slave, Leader, Standby, Online, Offline etc</li>
-</ul><div class="section"><h2>Roles<a name="Roles"></a></h2><p><img src="images/HELIX-components.png" alt="Helix Design" /></p><p>Not all nodes in a distributed system will perform similar functionality. For e.g, a few nodes might be serving requests, few nodes might be sending the request and some nodes might be controlling the nodes in the cluster. Based on functionality we have grouped them into</p><p>We have divided Helix in 3 logical components based on their responsibility </p>
+</ul><div class="section"><h2>Roles<a name="Roles"></a></h2><p><img src="images/HELIX-components.png" alt="Helix Design" /></p><p>Not all nodes in a distributed system will perform similar functionalities. For example, a few nodes might be serving requests and a few nodes might be sending requests, and some nodes might be controlling the nodes in the cluster. Thus, Helix categorizes nodes by their specific roles in the system.</p><p>We have divided Helix nodes into 3 logical components based on their responsibilities:</p>
<ol style="list-style-type: decimal">
- <li>PARTICIPANT: The nodes that actually host the distributed resources.</li>
- <li>SPECTATOR: The nodes that simply observe the PARTICIPANT State and route the request accordingly. Routers, for example, need to know the Instance on which a partition is hosted and its state in order to route the request to the appropriate end point.</li>
- <li>CONTROLLER: The controller observes and controls the PARTICIPANT nodes. It is responsible for coordinating all transitions in the cluster and ensuring that state constraints are satisfied and cluster stability is maintained.</li>
+ <li>Participant: The nodes that actually host the distributed resources.</li>
+ <li>Spectator: The nodes that simply observe the Participant state and route the request accordingly. Routers, for example, need to know the instance on which a partition is hosted and its state in order to route the request to the appropriate end point.</li>
+ <li>Controller: The controller observes and controls the Participant nodes. It is responsible for coordinating all transitions in the cluster and ensuring that state constraints are satisfied and cluster stability is maintained.</li>
</ol><p>These are simply logical components and can be deployed as per the system requirements. For example:</p>
<ol style="list-style-type: decimal">
- <li>Controller can be deployed as a separate service</li>
- <li>Controller can be deployed along with a Participant but only one Controller will be active at any given time.</li>
-</ol><p>Both have pros and cons, which will be discussed later and one can chose the mode of deployment as per system needs.</p></div><div class="section"><h2>Cluster state/metadata store<a name="Cluster_statemetadata_store"></a></h2><p>We need a distributed store to maintain the state of the cluster and a notification system to notify if there is any change in the cluster state. Helix uses Zookeeper to achieve this functionality.</p><p>Zookeeper provides:</p>
+ <li>The controller can be deployed as a separate service</li>
+ <li>The controller can be deployed along with a Participant but only one Controller will be active at any given time.</li>
+</ol><p>Both have pros and cons, which will be discussed later and one can chose the mode of deployment as per system needs.</p></div><div class="section"><h2>Cluster state metadata store<a name="Cluster_state_metadata_store"></a></h2><p>We need a distributed store to maintain the state of the cluster and a notification system to notify if there is any change in the cluster state. Helix uses Zookeeper to achieve this functionality.</p><p>Zookeeper provides:</p>
<ul>
<li>A way to represent PERSISTENT state which basically remains until its deleted.</li>
- <li>A way to represent TRANSIENT/EPHEMERAL state which vanishes when the process that created the STATE dies.</li>
- <li>Notification mechanism when there is a change in PERSISTENT/EPHEMERAL STATE</li>
-</ul><p>The namespace provided by ZooKeeper is much like that of a standard file system. A name is a sequence of path elements separated by a slash (/). Every node[ZNODE] in ZooKeeper's namespace is identified by a path.</p><p>More info on Zookeeper can be found here <a class="externalLink" href="http://zookeeper.apache.org">http://zookeeper.apache.org</a></p></div><div class="section"><h2>Statemachine and constraints<a name="Statemachine_and_constraints"></a></h2><p>Even though the concept of Resource, Partition, Replicas is common to most distributed systems, one thing that differentiates one distributed system from another is the way each partition is assigned a state and the constraints on each state.</p><p>For example:</p>
+ <li>A way to represent TRANSIENT/EPHEMERAL state which vanishes when the process that created the state dies.</li>
+ <li>Notification mechanism when there is a change in PERSISTENT and EPHEMERAL state</li>
+</ul><p>The namespace provided by ZooKeeper is much like that of a standard file system. A name is a sequence of path elements separated by a slash (/). Every node[ZNode] in ZooKeeper's namespace is identified by a path.</p><p>More info on Zookeeper can be found at <a class="externalLink" href="http://zookeeper.apache.org">http://zookeeper.apache.org</a></p></div><div class="section"><h2>State machine and constraints<a name="State_machine_and_constraints"></a></h2><p>Even though the concepts of Resources, Partitions, and Replicas are common to most distributed systems, one thing that differentiates one distributed system from another is the way each partition is assigned a state and the constraints on each state.</p><p>For example:</p>
<ol style="list-style-type: decimal">
- <li>If a system is serving READ ONLY data then all partition's replicas are equal and they can either be ONLINE or OFFLINE.</li>
- <li>If a system takes BOTH READ and WRITES but ensure that WRITES go through only one partition then the states will be MASTER, SLAVE and OFFLINE. Writes go through the MASTER and is replicated to the SLAVES. Optionally, READS can go through SLAVES.</li>
-</ol><p>Apart from defining STATE for each partition, the transition path to each STATE can be application specific. For example, in order to become MASTER it might be a requirement to first become a SLAVE. This ensures that if the SLAVE does not have the data as part of OFFLINE-SLAVE transition it can bootstrap data from other nodes in the system.</p><p>Helix provides a way to configure an application specific state machine along with constraints on each state. Along with constraints on STATE, Helix also provides a way to specify constraints on transitions. (More on this later.)</p>
+ <li>If a system is serving read-only data then all partition's replicas are equal and they can either be ONLINE or OFFLINE.</li>
+ <li>If a system takes <i>both</i> reads and writes but ensure that writes go through only one partition, the states will be MASTER, SLAVE, and OFFLINE. Writes go through the MASTER and replicate to the SLAVEs. Optionally, reads can go through SLAVES.</li>
+</ol><p>Apart from defining state for each partition, the transition path to each state can be application specific. For example, in order to become MASTER it might be a requirement to first become a SLAVE. This ensures that if the SLAVE does not have the data as part of OFFLINE-SLAVE transition it can bootstrap data from other nodes in the system.</p><p>Helix provides a way to configure an application specific state machine along with constraints on each state. Along with constraints on STATE, Helix also provides a way to specify constraints on transitions. (More on this later.)</p>
<div class="source"><pre class="prettyprint"> OFFLINE | SLAVE | MASTER
_____________________________
| | | |
@@ -243,15 +246,15 @@ MASTER | SLAVE | SLAVE | N/A |
</pre></div><p><img src="images/statemachine.png" alt="Helix Design" /></p></div><div class="section"><h2>Concepts<a name="Concepts"></a></h2><p>The following terminologies are used in Helix to model a state machine.</p>
<ul>
- <li>IDEALSTATE: The state in which we need the cluster to be in if all nodes are up and running. In other words, all state constraints are satisfied.</li>
- <li>CURRENTSTATE: Represents the current state of each node in the cluster</li>
- <li>EXTERNALVIEW: Represents the combined view of CURRENTSTATE of all nodes.</li>
-</ul><p>The goal of Helix is always to make the CURRENTSTATE of the system same as the IDEALSTATE. Some scenarios where this may not be true are:</p>
+ <li>IdealState: The state in which we need the cluster to be in if all nodes are up and running. In other words, all state constraints are satisfied.</li>
+ <li>CurrentState: Represents the actual current state of each node in the cluster</li>
+ <li>ExternalView: Represents the combined view of CurrentState of all nodes.</li>
+</ul><p>The goal of Helix is always to make the CurrentState of the system same as the IdealState. Some scenarios where this may not be true are:</p>
<ul>
<li>When all nodes are down</li>
<li>When one or more nodes fail</li>
<li>New nodes are added and the partitions need to be reassigned</li>
-</ul><div class="section"><h3>IDEALSTATE<a name="IDEALSTATE"></a></h3><p>Helix lets the application define the IdealState on a resource basis which basically consists of:</p>
+</ul><div class="section"><h3>IdealState<a name="IdealState"></a></h3><p>Helix lets the application define the IdealState on a resource basis which basically consists of:</p>
<ul>
<li>List of partitions. Example: 64</li>
<li>Number of replicas for each partition. Example: 3</li>
@@ -264,14 +267,14 @@ MASTER | SLAVE | SLAVE | N/A |
<li>..</li>
<li>..</li>
<li>Partition-p, replica-3, Slave, Node-n</li>
-</ul><p>Helix comes with various algorithms to automatically assign the partitions to nodes. The default algorithm minimizes the number of shuffles that happen when new nodes are added to the system</p></div><div class="section"><h3>CURRENTSTATE<a name="CURRENTSTATE"></a></h3><p>Every instance in the cluster hosts one or more partitions of a resource. Each of the partitions has a State associated with it.</p><p>Example Node-1</p>
+</ul><p>Helix comes with various algorithms to automatically assign the partitions to nodes. The default algorithm minimizes the number of shuffles that happen when new nodes are added to the system.</p></div><div class="section"><h3>CurrentState<a name="CurrentState"></a></h3><p>Every instance in the cluster hosts one or more partitions of a resource. Each of the partitions has a state associated with it.</p><p>Example Node-1</p>
<ul>
<li>Partition-1, Master</li>
<li>Partition-2, Slave</li>
<li>.</li>
<li>.</li>
<li>Partition-p, Slave</li>
-</ul></div><div class="section"><h3>EXTERNALVIEW<a name="EXTERNALVIEW"></a></h3><p>External clients needs to know the state of each partition in the cluster and the Node hosting that partition. Helix provides one view of the system to SPECTATORS as EXTERNAL VIEW. EXTERNAL VIEW is simply an aggregate of all CURRENTSTATE</p>
+</ul></div><div class="section"><h3>ExternalView<a name="ExternalView"></a></h3><p>External clients needs to know the state of each partition in the cluster and the Node hosting that partition. Helix provides one view of the system to Spectators as <i>ExternalView</i>. ExternalView is simply an aggregate of all node CurrentStates.</p>
<ul>
<li>Partition-1, replica-1, Master, Node-1</li>
<li>Partition-1, replica-2, Slave, Node-2</li>
@@ -281,24 +284,24 @@ MASTER | SLAVE | SLAVE | N/A |
<li>Partition-p, replica-3, Slave, Node-n</li>
</ul></div></div><div class="section"><h2>Process Workflow<a name="Process_Workflow"></a></h2><p>Mode of operation in a cluster</p><p>A node process can be one of the following:</p>
<ul>
- <li>PARTICIPANT: The process registers itself in the cluster and acts on the messages received in its queue and updates the current state. Example: Storage Node</li>
- <li>SPECTATOR: The process is simply interested in the changes in the Externalview. The Router is a spectator of the Storage cluster.</li>
- <li>CONTROLLER: This process actively controls the cluster by reacting to changes in Cluster State and sending messages to PARTICIPANTS.</li>
+ <li>Participant: The process registers itself in the cluster and acts on the messages received in its queue and updates the current state. Example: a storage node in a distributed database</li>
+ <li>Spectator: The process is simply interested in the changes in the Externalview.</li>
+ <li>Controller: This process actively controls the cluster by reacting to changes in cluster state and sending messages to Participants.</li>
</ul><div class="section"><h3>Participant Node Process<a name="Participant_Node_Process"></a></h3>
<ul>
- <li>When Node starts up, it registers itself under LIVEINSTANCES</li>
- <li>After registering, it waits for new Messages in the message queue</li>
+ <li>When Node starts up, it registers itself under <i>LiveInstances</i></li>
+ <li>After registering, it waits for new <i>Messages</i> in the message queue</li>
<li>When it receives a message, it will perform the required task as indicated in the message</li>
- <li>After the task is completed, depending on the task outcome it updates the CURRENTSTATE</li>
+ <li>After the task is completed, depending on the task outcome it updates the CurrentState</li>
</ul></div><div class="section"><h3>Controller Process<a name="Controller_Process"></a></h3>
<ul>
- <li>Watches IDEALSTATE</li>
- <li>Node goes down/comes up or Node is added/removed. Watches LIVEINSTANCES and CURRENTSTATE of each Node in the cluster</li>
- <li>Triggers appropriate state transition by sending message to PARTICIPANT</li>
+ <li>Watches IdealState</li>
+ <li>Notified when a node goes down/comes up or node is added/removed. Watches LiveInstances and CurrentState of each node in the cluster</li>
+ <li>Triggers appropriate state transitions by sending message to Participants</li>
</ul></div><div class="section"><h3>Spectator Process<a name="Spectator_Process"></a></h3>
<ul>
- <li>When the process starts, it asks cluster manager agent to be notified of changes in ExternalView</li>
- <li>Whenever it receives a notification, it reads the Externalview and performs required duties. For the Router, it updates its routing table.</li>
+ <li>When the process starts, it asks the Helix agent to be notified of changes in ExternalView</li>
+ <li>Whenever it receives a notification, it reads the Externalview and performs required duties.</li>
</ul><div class="section"><h4>Interaction between controller, participant and spectator<a name="Interaction_between_controller_participant_and_spectator"></a></h4><p>The following picture shows how controllers, participants and spectators interact with each other.</p><p><img src="images/helix-architecture.png" alt="Helix Architecture" /></p></div></div></div><div class="section"><h2>Core algorithm<a name="Core_algorithm"></a></h2>
<ul>
<li>Controller gets the IdealState and the CurrentState of active storage nodes from Zookeeper</li>
@@ -312,7 +315,7 @@ MASTER | SLAVE | SLAVE | N/A |
<li>Add the tasks in parallel if possible to the respective queue for each storage node (if the tasks added are mutually independent)</li>
<li>If a task is dependent on another task being completed, do not add that task</li>
<li>After any task is completed by a Participant, Controllers gets notified of the change and the State Transition algorithm is re-run until the CurrentState is same as IdealState.</li>
-</ul></div><div class="section"><h2>Helix znode layout<a name="Helix_znode_layout"></a></h2><p>Helix organizes znodes under clusterName in multiple levels. </p><p>The top level (under clusterName) znodes are all Helix defined and in upper case:</p>
+</ul></div><div class="section"><h2>Helix ZNode layout<a name="Helix_ZNode_layout"></a></h2><p>Helix organizes znodes under clusterName in multiple levels. </p><p>The top level (under the cluster name) ZNodes are all Helix-defined and in upper case:</p>
<ul>
<li>PROPERTYSTORE: application property store</li>
<li>STATEMODELDEFES: state model definitions</li>
@@ -322,7 +325,7 @@ MASTER | SLAVE | SLAVE | N/A |
<li>EXTERNALVIEW: external views</li>
<li>LIVEINSTANCES: live instances</li>
<li>CONTROLLER: cluster controller runtime information</li>
-</ul><p>Under INSTANCES, there are runtime znodes for each instance. An instance organizes znodes as follows:</p>
+</ul><p>Under INSTANCES, there are runtime ZNodes for each instance. An instance organizes ZNodes as follows:</p>
<ul>
<li>CURRENTSTATES
<ul>
Modified: incubator/helix/site-content/Concepts.html
URL: http://svn.apache.org/viewvc/incubator/helix/site-content/Concepts.html?rev=1519752&r1=1519751&r2=1519752&view=diff
==============================================================================
--- incubator/helix/site-content/Concepts.html (original)
+++ incubator/helix/site-content/Concepts.html Tue Sep 3 16:43:37 2013
@@ -1,13 +1,13 @@
<!DOCTYPE html>
<!--
- | Generated by Apache Maven Doxia at Aug 28, 2013
+ | Generated by Apache Maven Doxia at Sep 3, 2013
| Rendered using Apache Maven Fluido Skin 1.3.0
-->
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
- <meta name="Date-Revision-yyyymmdd" content="20130828" />
+ <meta name="Date-Revision-yyyymmdd" content="20130903" />
<meta http-equiv="Content-Language" content="en" />
<title>Apache Helix - </title>
<link rel="stylesheet" href="./css/apache-maven-fluido-1.3.0.min.css" />
@@ -86,6 +86,9 @@
<li> <a href="recipes/task_dag_execution.html" title="Distributed task DAG Execution">Distributed task DAG Execution</a>
</li>
+
+ <li> <a href="recipes/user_def_rebalancer.html" title="User-Defined Rebalancer Example">User-Defined Rebalancer Example</a>
+</li>
</ul>
</li>
<li class="dropdown">
@@ -168,7 +171,7 @@
- <li id="publishDate" class="pull-right">Last Published: 2013-08-28</li>
+ <li id="publishDate" class="pull-right">Last Published: 2013-09-03</li>
</ul>
</div>
@@ -211,7 +214,7 @@ under the License. --><p>Helix is based
}
}
}
-</pre></div></div><div class="section"><h3>Partition<a name="Partition"></a></h3><p>If this task get too big to fit on one box, you might want to divide it into subTasks. Each subTask is referred to as a <i>partition</i> in Helix. Let's say you want to divide the task into 3 subTasks/partitions, the IdealState can be changed as shown below. </p><p>'myTask_0', 'myTask_1', 'myTask_2' are logical names representing the partitions of myTask. Each tasks runs on N1, N2 and N3 respectively.</p>
+</pre></div></div><div class="section"><h3>Partition<a name="Partition"></a></h3><p>If this task get too big to fit on one box, you might want to divide it into subtasks. Each subtask is referred to as a <i>partition</i> in Helix. Let's say you want to divide the task into 3 subtasks/partitions, the IdealState can be changed as shown below. </p><p>'myTask_0', 'myTask_1', 'myTask_2' are logical names representing the partitions of myTask. Each tasks runs on N1, N2 and N3 respectively.</p>
<div class="source"><pre class="prettyprint">{
"id" : "myTask",
"simpleFields" : {
@@ -229,7 +232,7 @@ under the License. --><p>Helix is based
}
}
}
-</pre></div></div><div class="section"><h3>Replica<a name="Replica"></a></h3><p>Partitioning allows one to split the data/task into multiple subparts. But let's say the request rate each partition increases. The common solution is to have multiple copies for each partition. Helix refers to the copy of a partition as a <i>replica</i>. Adding a replica also increases the availability of the system during failures. One can see this methodology employed often in Search systems. The index is divided into shards, and each shard has multiple copies.</p><p>Let's say you want to add one additional replica for each task. The IdealState can simply be changed as shown below. </p><p>For increasing the availability of the system, it's better to place the replica of a given partition on different nodes.</p>
+</pre></div></div><div class="section"><h3>Replica<a name="Replica"></a></h3><p>Partitioning allows one to split the data/task into multiple subparts. But let's say the request rate for each partition increases. The common solution is to have multiple copies for each partition. Helix refers to the copy of a partition as a <i>replica</i>. Adding a replica also increases the availability of the system during failures. One can see this methodology employed often in search systems. The index is divided into shards, and each shard has multiple copies.</p><p>Let's say you want to add one additional replica for each task. The IdealState can simply be changed as shown below. </p><p>For increasing the availability of the system, it's better to place the replica of a given partition on different nodes.</p>
<div class="source"><pre class="prettyprint">{
"id" : "myIndex",
"simpleFields" : {
@@ -251,7 +254,7 @@ under the License. --><p>Helix is based
}
}
}
-</pre></div></div><div class="section"><h3>State<a name="State"></a></h3><p>Now let's take a slightly complicated scenario where a task represents a database. Unlike an index which is in general read-only, a database supports both reads and writes. Keeping the data consistent among the replicas is crucial in distributed data stores. One commonly applied technique is to assign one replica as MASTER and remaining replicas as SLAVE. All writes go to the MASTER and are then replicated to the SLAVE replicas.</p><p>Helix allows one to assign different states to each replica. Let's say you have two MySQL instances N1 and N2, where one will serve as MASTER and another as SLAVE. The IdealState can be changed to:</p>
+</pre></div></div><div class="section"><h3>State<a name="State"></a></h3><p>Now let's take a slightly more complicated scenario where a task represents a database. Unlike an index which is in general read-only, a database supports both reads and writes. Keeping the data consistent among the replicas is crucial in distributed data stores. One commonly applied technique is to assign one replica as the MASTER and remaining replicas as SLAVEs. All writes go to the MASTER and are then replicated to the SLAVE replicas.</p><p>Helix allows one to assign different states to each replica. Let's say you have two MySQL instances N1 and N2, where one will serve as MASTER and another as SLAVE. The IdealState can be changed to:</p>
<div class="source"><pre class="prettyprint">{
"id" : "myDB",
"simpleFields" : {
@@ -266,11 +269,11 @@ under the License. --><p>Helix is based
}
}
-</pre></div></div><div class="section"><h3>State Machine and Transitions<a name="State_Machine_and_Transitions"></a></h3><p>IdealState allows one to exactly specify the desired state of the cluster. Given an IdealState, Helix takes up the responsibility of ensuring that the cluster reaches the IdealState. The Helix <i>controller</i> reads the IdealState and then commands the Participant to take appropriate actions to move from one state to another until it matches the IdealState. These actions are referred to as <i>transitions</i> in Helix.</p><p>The next logical question is: how does the <i>controller</i> compute the transitions required to get to IdealState? This is where the finite state machine concept comes in. Helix allows applications to plug in a finite state machine. A state machine consists of the following:</p>
+</pre></div></div><div class="section"><h3>State Machine and Transitions<a name="State_Machine_and_Transitions"></a></h3><p>IdealState allows one to exactly specify the desired state of the cluster. Given an IdealState, Helix takes up the responsibility of ensuring that the cluster reaches the IdealState. The Helix <i>controller</i> reads the IdealState and then commands each Participant to take appropriate actions to move from one state to another until it matches the IdealState. These actions are referred to as <i>transitions</i> in Helix.</p><p>The next logical question is: how does the <i>controller</i> compute the transitions required to get to IdealState? This is where the finite state machine concept comes in. Helix allows applications to plug in a finite state machine. A state machine consists of the following:</p>
<ul>
<li>State: Describes the role of a replica</li>
- <li>Transition: An action that allows a replica to move from one State to another, thus changing its role.</li>
-</ul><p>Here is an example of MASTERSLAVE state machine,</p>
+ <li>Transition: An action that allows a replica to move from one state to another, thus changing its role.</li>
+</ul><p>Here is an example of MasterSlave state machine:</p>
<div class="source"><pre class="prettyprint"> OFFLINE | SLAVE | MASTER
_____________________________
| | | |
@@ -299,7 +302,7 @@ MASTER | SLAVE | SLAVE | N/A |
}
}
-</pre></div></div><div class="section"><h3>Current State<a name="Current_State"></a></h3><p>CurrentState of a resource simply represents its actual state at a PARTICIPANT. In the below example:</p>
+</pre></div></div><div class="section"><h3>Current State<a name="Current_State"></a></h3><p>CurrentState of a resource simply represents its actual state at a Participant. In the below example:</p>
<ul>
<li>INSTANCE_NAME: Unique name representing the process</li>
<li>SESSION_ID: ID that is automatically assigned every time a process joins the cluster</li>
@@ -323,7 +326,7 @@ MASTER | SLAVE | SLAVE | N/A |
}
}
}
-</pre></div><p>Each node in the cluster has its own CurrentState.</p></div><div class="section"><h3>External View<a name="External_View"></a></h3><p>In order to communicate with the PARTICIPANTs, external clients need to know the current state of each of the PARTICIPANTs. The external clients are referred to as SPECTATORS. In order to make the life of SPECTATOR simple, Helix provides an EXTERNALVIEW that is an aggregated view of the current state across all nodes. The EXTERNALVIEW has a similar format as IDEALSTATE.</p>
+</pre></div><p>Each node in the cluster has its own CurrentState.</p></div><div class="section"><h3>External View<a name="External_View"></a></h3><p>In order to communicate with the Participants, external clients need to know the current state of each of the Participants. The external clients are referred to as Spectators. In order to make the life of Spectator simple, Helix provides an ExternalView that is an aggregated view of the current state across all nodes. The ExternalView has a similar format as IdealState.</p>
<div class="source"><pre class="prettyprint">{
"id":"MyResource",
"mapFields":{
@@ -344,17 +347,17 @@ MASTER | SLAVE | SLAVE | N/A |
}
}
}
-</pre></div></div><div class="section"><h3>Rebalancer<a name="Rebalancer"></a></h3><p>The core component of Helix is the CONTROLLER which runs the REBALANCER algorithm on every cluster event. Cluster events can be one of the following:</p>
+</pre></div></div><div class="section"><h3>Rebalancer<a name="Rebalancer"></a></h3><p>The core component of Helix is the Controller which runs the Rebalancer algorithm on every cluster event. Cluster events can be one of the following:</p>
<ul>
<li>Nodes start/stop and soft/hard failures</li>
<li>New nodes are added/removed</li>
<li>Ideal state changes</li>
-</ul><p>There are few more such as config changes, etc. The key takeaway: there are many ways to trigger the rebalancer.</p><p>When a rebalancer is run it simply does the following:</p>
+</ul><p>There are few more examples such as configuration changes, etc. The key takeaway: there are many ways to trigger the rebalancer.</p><p>When a rebalancer is run it simply does the following:</p>
<ul>
<li>Compares the IdealState and current state</li>
<li>Computes the transitions required to reach the IdealState</li>
- <li>Issues the transitions to each PARTICIPANT</li>
-</ul><p>The above steps happen for every change in the system. Once the current state matches the IdealState, the system is considered stable which implies 'IDEALSTATE = CURRENTSTATE = EXTERNALVIEW'</p></div><div class="section"><h3>Dynamic IdealState<a name="Dynamic_IdealState"></a></h3><p>One of the things that makes Helix powerful is that IdealState can be changed dynamically. This means one can listen to cluster events like node failures and dynamically change the ideal state. Helix will then take care of triggering the respective transitions in the system.</p><p>Helix comes with a few algorithms to automatically compute the IdealState based on the constraints. For example, if you have a resource of 3 partitions and 2 replicas, Helix can automatically compute the IdealState based on the nodes that are currently active. See the <a href="./tutorial_rebalance.html">tutorial</a> to find out more about various execution modes of Helix like AUTO_REBALANCE, AUTO and CUSTOM. </p></div><
/div>
+ <li>Issues the transitions to each Participant</li>
+</ul><p>The above steps happen for every change in the system. Once the current state matches the IdealState, the system is considered stable which implies 'IdealState = CurrentState = ExternalView'</p></div><div class="section"><h3>Dynamic IdealState<a name="Dynamic_IdealState"></a></h3><p>One of the things that makes Helix powerful is that IdealState can be changed dynamically. This means one can listen to cluster events like node failures and dynamically change the ideal state. Helix will then take care of triggering the respective transitions in the system.</p><p>Helix comes with a few algorithms to automatically compute the IdealState based on the constraints. For example, if you have a resource of 3 partitions and 2 replicas, Helix can automatically compute the IdealState based on the nodes that are currently active. See the <a href="./tutorial_rebalance.html">tutorial</a> to find out more about various execution modes of Helix like FULL_AUTO, SEMI_AUTO and CUSTOMIZED. </p></d
iv></div>
</div>
</div>
Modified: incubator/helix/site-content/Features.html
URL: http://svn.apache.org/viewvc/incubator/helix/site-content/Features.html?rev=1519752&r1=1519751&r2=1519752&view=diff
==============================================================================
--- incubator/helix/site-content/Features.html (original)
+++ incubator/helix/site-content/Features.html Tue Sep 3 16:43:37 2013
@@ -1,13 +1,13 @@
<!DOCTYPE html>
<!--
- | Generated by Apache Maven Doxia at Aug 28, 2013
+ | Generated by Apache Maven Doxia at Sep 3, 2013
| Rendered using Apache Maven Fluido Skin 1.3.0
-->
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
- <meta name="Date-Revision-yyyymmdd" content="20130828" />
+ <meta name="Date-Revision-yyyymmdd" content="20130903" />
<meta http-equiv="Content-Language" content="en" />
<title>Apache Helix - </title>
<link rel="stylesheet" href="./css/apache-maven-fluido-1.3.0.min.css" />
@@ -86,6 +86,9 @@
<li> <a href="recipes/task_dag_execution.html" title="Distributed task DAG Execution">Distributed task DAG Execution</a>
</li>
+
+ <li> <a href="recipes/user_def_rebalancer.html" title="User-Defined Rebalancer Example">User-Defined Rebalancer Example</a>
+</li>
</ul>
</li>
<li class="dropdown">
@@ -168,7 +171,7 @@
- <li id="publishDate" class="pull-right">Last Published: 2013-08-28</li>
+ <li id="publishDate" class="pull-right">Last Published: 2013-09-03</li>
</ul>
</div>
Modified: incubator/helix/site-content/Quickstart.html
URL: http://svn.apache.org/viewvc/incubator/helix/site-content/Quickstart.html?rev=1519752&r1=1519751&r2=1519752&view=diff
==============================================================================
--- incubator/helix/site-content/Quickstart.html (original)
+++ incubator/helix/site-content/Quickstart.html Tue Sep 3 16:43:37 2013
@@ -1,13 +1,13 @@
<!DOCTYPE html>
<!--
- | Generated by Apache Maven Doxia at Aug 28, 2013
+ | Generated by Apache Maven Doxia at Sep 3, 2013
| Rendered using Apache Maven Fluido Skin 1.3.0
-->
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
- <meta name="Date-Revision-yyyymmdd" content="20130828" />
+ <meta name="Date-Revision-yyyymmdd" content="20130903" />
<meta http-equiv="Content-Language" content="en" />
<title>Apache Helix - </title>
<link rel="stylesheet" href="./css/apache-maven-fluido-1.3.0.min.css" />
@@ -86,6 +86,9 @@
<li> <a href="recipes/task_dag_execution.html" title="Distributed task DAG Execution">Distributed task DAG Execution</a>
</li>
+
+ <li> <a href="recipes/user_def_rebalancer.html" title="User-Defined Rebalancer Example">User-Defined Rebalancer Example</a>
+</li>
</ul>
</li>
<li class="dropdown">
@@ -168,7 +171,7 @@
- <li id="publishDate" class="pull-right">Last Published: 2013-08-28</li>
+ <li id="publishDate" class="pull-right">Last Published: 2013-09-03</li>
</ul>
</div>
@@ -250,7 +253,7 @@ chmod +x *
<li>Verify that the cluster is healthy and inspect the Helix view</li>
<li>Expand the cluster: add a few nodes and rebalance the partitions</li>
<li>Failover: stop a node and verify the mastership transfer</li>
-</ul><div class="section"><h3>Install/Start zookeeper<a name="InstallStart_zookeeper"></a></h3><p>Zookeeper can be started in standalone mode or replicated mode.</p><p>More info is available at </p>
+</ul><div class="section"><h3>Install and Start Zookeeper<a name="Install_and_Start_Zookeeper"></a></h3><p>Zookeeper can be started in standalone mode or replicated mode.</p><p>More info is available at </p>
<ul>
<li><a class="externalLink" href="http://zookeeper.apache.org/doc/r3.3.3/zookeeperStarted.html">http://zookeeper.apache.org/doc/r3.3.3/zookeeperStarted.html</a></li>
<li><a class="externalLink" href="http://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_zkMulitServerSetup">http://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_zkMulitServerSetup</a></li>
@@ -368,7 +371,7 @@ IdealState for myDB:
"myDB_5" : [ "localhost_12914", "localhost_12915", "localhost_12913" ]
},
"simpleFields" : {
- "IDEAL_STATE_MODE" : "AUTO",
+ "REBALANCE_MODE" : "SEMI_AUTO",
"NUM_PARTITIONS" : "6",
"REPLICAS" : "3",
"STATE_MODEL_DEF_REF" : "MasterSlave",
@@ -478,7 +481,7 @@ IdealState for myDB:
"myDB_5" : [ "localhost_12914", "localhost_12915", "localhost_12913" ]
},
"simpleFields" : {
- "IDEAL_STATE_MODE" : "AUTO",
+ "REBALANCE_MODE" : "SEMI_AUTO",
"NUM_PARTITIONS" : "6",
"REPLICAS" : "3",
"STATE_MODEL_DEF_REF" : "MasterSlave",
@@ -574,7 +577,7 @@ IdealState for myDB:
"myDB_5" : [ "localhost_12914", "localhost_12915", "localhost_12913" ]
},
"simpleFields" : {
- "IDEAL_STATE_MODE" : "AUTO",
+ "REBALANCE_MODE" : "SEMI_AUTO",
"NUM_PARTITIONS" : "6",
"REPLICAS" : "3",
"STATE_MODEL_DEF_REF" : "MasterSlave",
@@ -619,7 +622,7 @@ ExternalView for myDB:
"BUCKET_SIZE" : "0"
}
}
-</pre></div><p>As we've seen in this Quickstart, Helix takes care of partitioning, load balancing, elasticity, failure detection and recovery.</p><div class="section"><h5>ZOOINSPECTOR<a name="ZOOINSPECTOR"></a></h5><p>You can view all of the underlying data by going direct to zookeeper. Use ZooInspector that comes with zookeeper to browse the data. This is a java applet (make sure you have X windows)</p><p>To start zooinspector run the following command from <zk_install_directory>/contrib/ZooInspector</p>
+</pre></div><p>As we've seen in this Quickstart, Helix takes care of partitioning, load balancing, elasticity, failure detection and recovery.</p><div class="section"><h5>ZooInspector<a name="ZooInspector"></a></h5><p>You can view all of the underlying data by going direct to zookeeper. Use ZooInspector that comes with zookeeper to browse the data. This is a java applet (make sure you have X windows)</p><p>To start zooinspector run the following command from <zk_install_directory>/contrib/ZooInspector</p>
<div class="source"><pre class="prettyprint">java -cp zookeeper-3.3.3-ZooInspector.jar:lib/jtoaster-1.0.4.jar:../../lib/log4j-1.2.15.jar:../../zookeeper-3.3.3.jar org.apache.zookeeper.inspector.ZooInspector
</pre></div></div></div><div class="section"><h4>Next<a name="Next"></a></h4><p>Now that you understand the idea of Helix, read the <a href="./tutorial.html">tutorial</a> to learn how to choose the right state model and constraints for your system, and how to implement it. In many cases, the built-in features meet your requirements. And best of all, Helix is a customizable framework, so you can plug in your own behavior, while retaining the automation provided by Helix.</p></div></div></div>
</div>
Modified: incubator/helix/site-content/Tutorial.html
URL: http://svn.apache.org/viewvc/incubator/helix/site-content/Tutorial.html?rev=1519752&r1=1519751&r2=1519752&view=diff
==============================================================================
--- incubator/helix/site-content/Tutorial.html (original)
+++ incubator/helix/site-content/Tutorial.html Tue Sep 3 16:43:37 2013
@@ -1,13 +1,13 @@
<!DOCTYPE html>
<!--
- | Generated by Apache Maven Doxia at Aug 28, 2013
+ | Generated by Apache Maven Doxia at Sep 3, 2013
| Rendered using Apache Maven Fluido Skin 1.3.0
-->
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
- <meta name="Date-Revision-yyyymmdd" content="20130828" />
+ <meta name="Date-Revision-yyyymmdd" content="20130903" />
<meta http-equiv="Content-Language" content="en" />
<title>Apache Helix - </title>
<link rel="stylesheet" href="./css/apache-maven-fluido-1.3.0.min.css" />
@@ -86,6 +86,9 @@
<li> <a href="recipes/task_dag_execution.html" title="Distributed task DAG Execution">Distributed task DAG Execution</a>
</li>
+
+ <li> <a href="recipes/user_def_rebalancer.html" title="User-Defined Rebalancer Example">User-Defined Rebalancer Example</a>
+</li>
</ul>
</li>
<li class="dropdown">
@@ -168,7 +171,7 @@
- <li id="publishDate" class="pull-right">Last Published: 2013-08-28</li>
+ <li id="publishDate" class="pull-right">Last Published: 2013-09-03</li>
</ul>
</div>
@@ -204,12 +207,14 @@ under the License. --><h1>Helix Tutorial
<li><a href="./tutorial_spectator.html">Spectator</a></li>
<li><a href="./tutorial_controller.html">Controller</a></li>
<li><a href="./tutorial_rebalance.html">Rebalancing Algorithms</a></li>
+ <li><a href="./tutorial_user_def_rebalancer.html">User-Defined Rebalancing</a></li>
<li><a href="./tutorial_state.html">State Machines</a></li>
<li><a href="./tutorial_messaging.html">Messaging</a></li>
<li><a href="./tutorial_health.html">Customized health check</a></li>
<li><a href="./tutorial_throttling.html">Throttling</a></li>
<li><a href="./tutorial_propstore.html">Application Property Store</a></li>
<li><a href="./tutorial_admin.html">Admin Interface</a></li>
+ <li><a href="./tutorial_yaml.html">YAML Cluster Setup</a></li>
</ol></div><div class="section"><h3>Preliminaries<a name="Preliminaries"></a></h3><p>First, we need to set up the system. Let's walk through the steps in building a distributed system using Helix.</p></div><div class="section"><h3>Start Zookeeper<a name="Start_Zookeeper"></a></h3><p>This starts a zookeeper in standalone mode. For production deployment, see <a class="externalLink" href="http://zookeeper.apache.org">Apache Zookeeper</a> for instructions.</p>
<div class="source"><pre class="prettyprint"> ./start-standalone-zookeeper.sh 2199 &
</pre></div></div><div class="section"><h3>Create a cluster<a name="Create_a_cluster"></a></h3><p>Creating a cluster will define the cluster in appropriate znodes on zookeeper. </p><p>Using the java API:</p>
@@ -288,14 +293,14 @@ under the License. --><h1>Helix Tutorial
admin.addStateModelDef(CLUSTER_NAME, STATE_MODEL_NAME, myStateModel);
</pre></div></div><div class="section"><h4>Assigning partitions to nodes<a name="Assigning_partitions_to_nodes"></a></h4><p>The final goal of Helix is to ensure that the constraints on the state model are satisfied. Helix does this by assigning a STATE to a partition (such as MASTER, SLAVE), and placing it on a particular node.</p><p>There are 3 assignment modes Helix can operate on</p>
<ul>
- <li>AUTO_REBALANCE: Helix decides the placement and state of a partition.</li>
- <li>AUTO: Application decides the placement but Helix decides the state of a partition.</li>
- <li>CUSTOM: Application controls the placement and state of a partition.</li>
+ <li>FULL_AUTO: Helix decides the placement and state of a partition.</li>
+ <li>SEMI_AUTO: Application decides the placement but Helix decides the state of a partition.</li>
+ <li>CUSTOMIZED: Application controls the placement and state of a partition.</li>
</ul><p>For more info on the assignment modes, see <a href="./tutorial_rebalance.html">Rebalancing Algorithms</a> of the tutorial.</p>
<div class="source"><pre class="prettyprint"> String RESOURCE_NAME = "MyDB";
int NUM_PARTITIONS = 6;
STATE_MODEL_NAME = "MasterSlave";
- String MODE = "AUTO";
+ String MODE = "SEMI_AUTO";
int NUM_REPLICAS = 2;
admin.addResource(CLUSTER_NAME, RESOURCE_NAME, NUM_PARTITIONS, STATE_MODEL_NAME, MODE);
Modified: incubator/helix/site-content/UseCases.html
URL: http://svn.apache.org/viewvc/incubator/helix/site-content/UseCases.html?rev=1519752&r1=1519751&r2=1519752&view=diff
==============================================================================
--- incubator/helix/site-content/UseCases.html (original)
+++ incubator/helix/site-content/UseCases.html Tue Sep 3 16:43:37 2013
@@ -1,13 +1,13 @@
<!DOCTYPE html>
<!--
- | Generated by Apache Maven Doxia at Aug 28, 2013
+ | Generated by Apache Maven Doxia at Sep 3, 2013
| Rendered using Apache Maven Fluido Skin 1.3.0
-->
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
- <meta name="Date-Revision-yyyymmdd" content="20130828" />
+ <meta name="Date-Revision-yyyymmdd" content="20130903" />
<meta http-equiv="Content-Language" content="en" />
<title>Apache Helix - </title>
<link rel="stylesheet" href="./css/apache-maven-fluido-1.3.0.min.css" />
@@ -86,6 +86,9 @@
<li> <a href="recipes/task_dag_execution.html" title="Distributed task DAG Execution">Distributed task DAG Execution</a>
</li>
+
+ <li> <a href="recipes/user_def_rebalancer.html" title="User-Defined Rebalancer Example">User-Defined Rebalancer Example</a>
+</li>
</ul>
</li>
<li class="dropdown">
@@ -168,7 +171,7 @@
- <li id="publishDate" class="pull-right">Last Published: 2013-08-28</li>
+ <li id="publishDate" class="pull-right">Last Published: 2013-09-03</li>
</ul>
</div>
Modified: incubator/helix/site-content/apidocs/assets/navtree_data.js
URL: http://svn.apache.org/viewvc/incubator/helix/site-content/apidocs/assets/navtree_data.js?rev=1519752&r1=1519751&r2=1519752&view=diff
==============================================================================
--- incubator/helix/site-content/apidocs/assets/navtree_data.js (original)
+++ incubator/helix/site-content/apidocs/assets/navtree_data.js Tue Sep 3 16:43:37 2013
@@ -10,7 +10,7 @@ var NAVTREE_DATA =
, "" ], [ "org.apache.helix.alerts", "org/apache/helix/alerts/package-summary.html", [ [ "Classes", null, [ [ "AccumulateAggregator", "org/apache/helix/alerts/AccumulateAggregator.html", null, "" ], [ "Aggregator", "org/apache/helix/alerts/Aggregator.html", null, "" ], [ "Alert", "org/apache/helix/alerts/Alert.html", null, "" ], [ "AlertComparator", "org/apache/helix/alerts/AlertComparator.html", null, "" ], [ "AlertParser", "org/apache/helix/alerts/AlertParser.html", null, "" ], [ "AlertProcessor", "org/apache/helix/alerts/AlertProcessor.html", null, "" ], [ "AlertsHolder", "org/apache/helix/alerts/AlertsHolder.html", null, "" ], [ "AlertValueAndStatus", "org/apache/helix/alerts/AlertValueAndStatus.html", null, "" ], [ "DecayAggregator", "org/apache/helix/alerts/DecayAggregator.html", null, "" ], [ "DivideOperator", "org/apache/helix/alerts/DivideOperator.html", null, "" ], [ "ExpandOperator", "org/apache/helix/alerts/ExpandOperator.html", null, "" ], [ "ExpressionParser", "org/apa
che/helix/alerts/ExpressionParser.html", null, "" ], [ "GreaterAlertComparator", "org/apache/helix/alerts/GreaterAlertComparator.html", null, "" ], [ "MultiplyOperator", "org/apache/helix/alerts/MultiplyOperator.html", null, "" ], [ "Operator", "org/apache/helix/alerts/Operator.html", null, "" ], [ "Stat", "org/apache/helix/alerts/Stat.html", null, "" ], [ "StatsHolder", "org/apache/helix/alerts/StatsHolder.html", null, "" ], [ "SumEachOperator", "org/apache/helix/alerts/SumEachOperator.html", null, "" ], [ "SumOperator", "org/apache/helix/alerts/SumOperator.html", null, "" ], [ "Tuple", "org/apache/helix/alerts/Tuple.html", null, "" ], [ "WindowAggregator", "org/apache/helix/alerts/WindowAggregator.html", null, "" ] ]
, "" ], [ "Enums", null, [ [ "ExpressionOperatorType", "org/apache/helix/alerts/ExpressionOperatorType.html", null, "" ] ]
, "" ] ]
-, "" ], [ "org.apache.helix.controller", "org/apache/helix/controller/package-summary.html", [ [ "Classes", null, [ [ "GenericHelixController", "org/apache/helix/controller/GenericHelixController.html", null, "" ], [ "HelixControllerMain", "org/apache/helix/controller/HelixControllerMain.html", null, "" ], [ "HierarchicalDataHolder", "org/apache/helix/controller/HierarchicalDataHolder.html", null, "" ] ]
+, "" ], [ "org.apache.helix.controller", "org/apache/helix/controller/package-summary.html", [ [ "Classes", null, [ [ "ExternalViewGenerator", "org/apache/helix/controller/ExternalViewGenerator.html", null, "" ], [ "GenericHelixController", "org/apache/helix/controller/GenericHelixController.html", null, "" ], [ "HelixControllerMain", "org/apache/helix/controller/HelixControllerMain.html", null, "" ], [ "HierarchicalDataHolder", "org/apache/helix/controller/HierarchicalDataHolder.html", null, "" ] ]
, "" ] ]
, "" ], [ "org.apache.helix.controller.pipeline", "org/apache/helix/controller/pipeline/package-summary.html", [ [ "Interfaces", null, [ [ "Stage", "org/apache/helix/controller/pipeline/Stage.html", null, "" ] ]
, "" ], [ "Classes", null, [ [ "AbstractBaseStage", "org/apache/helix/controller/pipeline/AbstractBaseStage.html", null, "" ], [ "Pipeline", "org/apache/helix/controller/pipeline/Pipeline.html", null, "" ], [ "PipelineRegistry", "org/apache/helix/controller/pipeline/PipelineRegistry.html", null, "" ], [ "StageContext", "org/apache/helix/controller/pipeline/StageContext.html", null, "" ] ]
@@ -91,9 +91,11 @@ var NAVTREE_DATA =
, "" ], [ "Classes", null, [ [ "AnalyticsTaskFactory", "org/apache/helix/taskexecution/AnalyticsTaskFactory.html", null, "" ], [ "CountTask", "org/apache/helix/taskexecution/CountTask.html", null, "" ], [ "Dag", "org/apache/helix/taskexecution/Dag.html", null, "" ], [ "Dag.Node", "org/apache/helix/taskexecution/Dag.Node.html", null, "" ], [ "FilterTask", "org/apache/helix/taskexecution/FilterTask.html", null, "" ], [ "JoinTask", "org/apache/helix/taskexecution/JoinTask.html", null, "" ], [ "RedisTaskResultStore", "org/apache/helix/taskexecution/RedisTaskResultStore.html", null, "" ], [ "ReportTask", "org/apache/helix/taskexecution/ReportTask.html", null, "" ], [ "Task", "org/apache/helix/taskexecution/Task.html", null, "" ], [ "TaskCluster", "org/apache/helix/taskexecution/TaskCluster.html", null, "" ], [ "TaskExecutionDemo", "org/apache/helix/taskexecution/TaskExecutionDemo.html", null, "" ], [ "TaskStateModel", "org/apache/helix/taskexecution/TaskStateModel.html", null, "" ], [ "T
askStateModelFactory", "org/apache/helix/taskexecution/TaskStateModelFactory.html", null, "" ], [ "Worker", "org/apache/helix/taskexecution/Worker.html", null, "" ] ]
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Modified: incubator/helix/site-content/apidocs/reference/classes.html
URL: http://svn.apache.org/viewvc/incubator/helix/site-content/apidocs/reference/classes.html?rev=1519752&r1=1519751&r2=1519752&view=diff
==============================================================================
--- incubator/helix/site-content/apidocs/reference/classes.html (original)
+++ incubator/helix/site-content/apidocs/reference/classes.html Tue Sep 3 16:43:37 2013
@@ -208,6 +208,8 @@
<li class="api apilevel-">
<a href="./org/apache/helix/tools/package-summary.html">org.apache.helix.tools</a></li>
<li class="api apilevel-">
+ <a href="./org/apache/helix/userdefinedrebalancer/package-summary.html">org.apache.helix.userdefinedrebalancer</a></li>
+ <li class="api apilevel-">
<a href="./org/apache/helix/util/package-summary.html">org.apache.helix.util</a></li>
<li class="api apilevel-">
<a href="./org/apache/helix/webapp/package-summary.html">org.apache.helix.webapp</a></li>
@@ -280,6 +282,7 @@
<a href="#letter_S">S</a>
<a href="#letter_T">T</a>
<a href="#letter_W">W</a>
+ <a href="#letter_Y">Y</a>
<a href="#letter_Z">Z</a>
</div>
@@ -1314,6 +1317,12 @@
<tr class=" api apilevel-" >
+ <td class="jd-linkcol"><a href="./org/apache/helix/controller/ExternalViewGenerator.html">ExternalViewGenerator</a></td>
+ <td class="jd-descrcol" width="100%"> </td>
+ </tr>
+
+
+ <tr class="alt-color api apilevel-" >
<td class="jd-linkcol"><a href="./org/apache/helix/webapp/resources/ExternalViewResource.html">ExternalViewResource</a></td>
<td class="jd-descrcol" width="100%"> </td>
</tr>
@@ -1940,11 +1949,24 @@
<tr class=" api apilevel-" >
+ <td class="jd-linkcol"><a href="./org/apache/helix/userdefinedrebalancer/Lock.html">Lock</a></td>
+ <td class="jd-descrcol" width="100%"> </td>
+ </tr>
+
+
+ <tr class="alt-color api apilevel-" >
<td class="jd-linkcol"><a href="./org/apache/helix/lockmanager/LockFactory.html">LockFactory</a></td>
<td class="jd-descrcol" width="100%"> </td>
</tr>
+ <tr class=" api apilevel-" >
+ <td class="jd-linkcol"><a href="./org/apache/helix/userdefinedrebalancer/LockFactory.html">LockFactory</a></td>
+ <td class="jd-descrcol" width="100%">This factory allows a participant to get the appropriate state model callbacks for the lock
+ manager state model. </td>
+ </tr>
+
+
<tr class="alt-color api apilevel-" >
<td class="jd-linkcol"><a href="./org/apache/helix/lockmanager/LockManagerDemo.html">LockManagerDemo</a></td>
<td class="jd-descrcol" width="100%"> </td>
@@ -1952,11 +1974,29 @@
<tr class=" api apilevel-" >
+ <td class="jd-linkcol"><a href="./org/apache/helix/userdefinedrebalancer/LockManagerDemo.html">LockManagerDemo</a></td>
+ <td class="jd-descrcol" width="100%"> </td>
+ </tr>
+
+
+ <tr class="alt-color api apilevel-" >
+ <td class="jd-linkcol"><a href="./org/apache/helix/userdefinedrebalancer/LockManagerRebalancer.html">LockManagerRebalancer</a></td>
+ <td class="jd-descrcol" width="100%"> </td>
+ </tr>
+
+
+ <tr class=" api apilevel-" >
<td class="jd-linkcol"><a href="./org/apache/helix/lockmanager/LockProcess.html">LockProcess</a></td>
<td class="jd-descrcol" width="100%"> </td>
</tr>
+ <tr class="alt-color api apilevel-" >
+ <td class="jd-linkcol"><a href="./org/apache/helix/userdefinedrebalancer/LockProcess.html">LockProcess</a></td>
+ <td class="jd-descrcol" width="100%"> </td>
+ </tr>
+
+
</table>
@@ -3030,6 +3070,63 @@
</table>
+<h2 id="letter_Y">Y</h2>
+<table class="jd-sumtable">
+
+
+ <tr class="alt-color api apilevel-" >
+ <td class="jd-linkcol"><a href="./org/apache/helix/tools/YAMLClusterSetup.html">YAMLClusterSetup</a></td>
+ <td class="jd-descrcol" width="100%">Supports HelixAdmin operations specified by a YAML configuration file defining a cluster,
+ resources, participants, etc. </td>
+ </tr>
+
+
+ <tr class=" api apilevel-" >
+ <td class="jd-linkcol"><a href="./org/apache/helix/tools/YAMLClusterSetup.YAMLClusterConfig.html">YAMLClusterSetup.YAMLClusterConfig</a></td>
+ <td class="jd-descrcol" width="100%">Java wrapper for the YAML input file
+ </td>
+ </tr>
+
+
+ <tr class="alt-color api apilevel-" >
+ <td class="jd-linkcol"><a href="./org/apache/helix/tools/YAMLClusterSetup.YAMLClusterConfig.ParticipantConfig.html">YAMLClusterSetup.YAMLClusterConfig.ParticipantConfig</a></td>
+ <td class="jd-descrcol" width="100%"> </td>
+ </tr>
+
+
+ <tr class=" api apilevel-" >
+ <td class="jd-linkcol"><a href="./org/apache/helix/tools/YAMLClusterSetup.YAMLClusterConfig.ResourceConfig.html">YAMLClusterSetup.YAMLClusterConfig.ResourceConfig</a></td>
+ <td class="jd-descrcol" width="100%"> </td>
+ </tr>
+
+
+ <tr class="alt-color api apilevel-" >
+ <td class="jd-linkcol"><a href="./org/apache/helix/tools/YAMLClusterSetup.YAMLClusterConfig.ResourceConfig.ConstraintsConfig.html">YAMLClusterSetup.YAMLClusterConfig.ResourceConfig.ConstraintsConfig</a></td>
+ <td class="jd-descrcol" width="100%"> </td>
+ </tr>
+
+
+ <tr class=" api apilevel-" >
+ <td class="jd-linkcol"><a href="./org/apache/helix/tools/YAMLClusterSetup.YAMLClusterConfig.ResourceConfig.ConstraintsConfig.StateConstraintsConfig.html">YAMLClusterSetup.YAMLClusterConfig.ResourceConfig.ConstraintsConfig.StateConstraintsConfig</a></td>
+ <td class="jd-descrcol" width="100%"> </td>
+ </tr>
+
+
+ <tr class="alt-color api apilevel-" >
+ <td class="jd-linkcol"><a href="./org/apache/helix/tools/YAMLClusterSetup.YAMLClusterConfig.ResourceConfig.ConstraintsConfig.TransitionConstraintsConfig.html">YAMLClusterSetup.YAMLClusterConfig.ResourceConfig.ConstraintsConfig.TransitionConstraintsConfig</a></td>
+ <td class="jd-descrcol" width="100%"> </td>
+ </tr>
+
+
+ <tr class=" api apilevel-" >
+ <td class="jd-linkcol"><a href="./org/apache/helix/tools/YAMLClusterSetup.YAMLClusterConfig.ResourceConfig.StateModelConfig.html">YAMLClusterSetup.YAMLClusterConfig.ResourceConfig.StateModelConfig</a></td>
+ <td class="jd-descrcol" width="100%"> </td>
+ </tr>
+
+
+</table>
+
+
<h2 id="letter_Z">Z</h2>
<table class="jd-sumtable">