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Posted to users@kafka.apache.org by Bryan Duggan <br...@boxever.com> on 2018/09/20 10:31:53 UTC
Problems trying to make kafka 'rack-aware'
Hi,
I have a kafka cluster consisting of 3 brokers across 3 different AWS
availability zones. It hosts several topics, each of which has a
replication factor of 3. The cluster is currently not 'rack-aware'.
I am trying to do the following;
- add 3 additional brokers (one in each of the 3 AZs)
- make the cluster 'rack-aware'. (ie: create 3 racks on a per-AZ
basic, each containing 2 brokers)
- reassign the topics with the intention of having 1 replica in
each of the 3 racks.
To achieve this I've added 'broker.rack' to the properties file for each
broker. The rack name is the same as the AZ name each broker is in. I've
restarted kafka on all brokers (in case that's required for
rack-awareness to take effect).
Following restart I've attempted to reassign topics across all 6 brokers
by running the following;
- ./kafka-reassign-partitions.sh --zookeeper $ZK
--topics-to-move-json-file topics-to-move.json --broker-list '1,2,3,4,5,6'
(where topics-to-move.json is a simple json file containing the topics
to reassign)
The problem I am having is, after running 'kafka-reassign-partitions.sh'
with 6 brokers listed in the broker-list, it doesn't honour
rack-awareness, and instead assigns 2 partitions to brokers in a single
rack with a 3rd being assigned elsewhere.
The version of kafka I am using is 2.11-1.1.1.
Any documentation I've read suggests the above should have achieved what
I want. However, it is not working as expected.
Has anyone else make their kafka cluster 'rack-aware'? If so, did you
experience any issues doing so?
Or, can anyone tell me if there's some step I'm missing to make this work.
TIA
Bryan
Re: Problems trying to make kafka 'rack-aware'
Posted by Bryan Duggan <br...@boxever.com>.
Hi Eno,
many thanks for trying that. That is very helpful for me.
That basic check didn't work for me but I have since discovered what my
issue was. Despite using a version of kafka that supports rack-awareness
we have been deliberately setting 'inter.broker.protocol.version' to an
older version (due to various issues with some of our consumers). When I
update this parameter to use a later version, I can see 'rack' being
written to zookeeper.
For now I need to turn my attention to resolving the issues with my
consumers.
Thanks again for helping out.
Bryan
On 21/09/2018 14:52, Eno Thereska wrote:
> Hi Bryan,
>
> I did a simple check with starting a broker with no rack id and then
> restarting with a rack id and I can confirm I could get the rack id from
> zookeeper after the restart. This was on trunk. Does that basic check work
> for you (i.e., without reassigning partitions)?
>
> Thanks
> Eno
>
> On Fri, Sep 21, 2018 at 2:07 PM, Bryan Duggan <br...@boxever.com>
> wrote:
>
>> I didn't get a response to this, but I've been investigating more and can
>> now frame the problem slightly differently (hopefully, more accurately).
>>
>> According to this document
>>
>> https://cwiki.apache.org/confluence/display/KAFKA/Kafka+
>> data+structures+in+Zookeeper
>>
>> Which defines broker data structures in zookeeper, the following is the
>> broker schema (from version 0.10 onwards - I am using version 0.11)
>>
>> { "fields":
>> [ {"name": "version", "type": "int", "doc": "version id"},
>> {"name": "host", "type": "string", "doc": "ip address or host name
>> of the broker"},
>> {"name": "port", "type": "int", "doc": "port of the broker"},
>> {"name": "jmx_port", "type": "int", "doc": "port for jmx"}
>> {"name": "endpoints", "type": "array", "items": "string", "doc":
>> "endpoints supported by the broker"}
>> {"name": "rack", "type": "string", "doc": "Rack of the broker.
>> Optional. This will be used in rack aware replication assignment for fault
>> tolerance."}
>> ]
>> }
>>
>> when I check my broker data in zookeeper (which has a non-null broker.rack
>> setting in the properties file), I have the following;
>>
>> {"endpoints":["PLAINTEXT://x.x.x.x.abcd:9092"],"jmx_port":-1
>> ,"host":"x.x.x.x.abc","timestamp":"1537527988341","port":9092,"version":2}
>>
>> there is no 'rack'.
>>
>> In the server.log file on my kafka broker I see;
>> ----
>> [2018-09-21 13:00:40,227] INFO KafkaConfig values:
>> advertised.host.name = null
>> .
>> .
>> broker.id = 1234567
>> broker.rack = rack1
>> compression.type = producer
>> .
>> -----
>>
>> so it looks fine from the broker side. However, when I restart kafka on
>> the host, it doesn't load any rack information into zookeeper.
>>
>> Can someone please confirm to me, if I have rack awareness, should I
>> expect to see a value for 'rack' in zookeeper? If so, do I need to do
>> something else on the broker side to get it to include it as part of the
>> meta-data it writes (as far as I can see it writes the metadata each time
>> kafka is restarted).
>>
>> thanks
>> Bryan
>>
>>
>>
>>
>>
>>
>>
>>
>> On 20/09/2018 11:31, Bryan Duggan wrote:
>>
>>> Hi,
>>>
>>> I have a kafka cluster consisting of 3 brokers across 3 different AWS
>>> availability zones. It hosts several topics, each of which has a
>>> replication factor of 3. The cluster is currently not 'rack-aware'.
>>>
>>> I am trying to do the following;
>>>
>>> - add 3 additional brokers (one in each of the 3 AZs)
>>>
>>> - make the cluster 'rack-aware'. (ie: create 3 racks on a per-AZ
>>> basic, each containing 2 brokers)
>>>
>>> - reassign the topics with the intention of having 1 replica in each
>>> of the 3 racks.
>>>
>>> To achieve this I've added 'broker.rack' to the properties file for each
>>> broker. The rack name is the same as the AZ name each broker is in. I've
>>> restarted kafka on all brokers (in case that's required for rack-awareness
>>> to take effect).
>>>
>>> Following restart I've attempted to reassign topics across all 6 brokers
>>> by running the following;
>>>
>>> - ./kafka-reassign-partitions.sh --zookeeper $ZK
>>> --topics-to-move-json-file topics-to-move.json --broker-list '1,2,3,4,5,6'
>>>
>>> (where topics-to-move.json is a simple json file containing the topics to
>>> reassign)
>>>
>>> The problem I am having is, after running 'kafka-reassign-partitions.sh'
>>> with 6 brokers listed in the broker-list, it doesn't honour
>>> rack-awareness, and instead assigns 2 partitions to brokers in a single
>>> rack with a 3rd being assigned elsewhere.
>>>
>>> The version of kafka I am using is 2.11-1.1.1.
>>>
>>> Any documentation I've read suggests the above should have achieved what
>>> I want. However, it is not working as expected.
>>>
>>> Has anyone else make their kafka cluster 'rack-aware'? If so, did you
>>> experience any issues doing so?
>>>
>>> Or, can anyone tell me if there's some step I'm missing to make this work.
>>>
>>> TIA
>>>
>>> Bryan
>>>
>>>
>>>
>>>
Re: Problems trying to make kafka 'rack-aware'
Posted by Eno Thereska <en...@gmail.com>.
Hi Bryan,
I did a simple check with starting a broker with no rack id and then
restarting with a rack id and I can confirm I could get the rack id from
zookeeper after the restart. This was on trunk. Does that basic check work
for you (i.e., without reassigning partitions)?
Thanks
Eno
On Fri, Sep 21, 2018 at 2:07 PM, Bryan Duggan <br...@boxever.com>
wrote:
>
> I didn't get a response to this, but I've been investigating more and can
> now frame the problem slightly differently (hopefully, more accurately).
>
> According to this document
>
> https://cwiki.apache.org/confluence/display/KAFKA/Kafka+
> data+structures+in+Zookeeper
>
> Which defines broker data structures in zookeeper, the following is the
> broker schema (from version 0.10 onwards - I am using version 0.11)
>
> { "fields":
> [ {"name": "version", "type": "int", "doc": "version id"},
> {"name": "host", "type": "string", "doc": "ip address or host name
> of the broker"},
> {"name": "port", "type": "int", "doc": "port of the broker"},
> {"name": "jmx_port", "type": "int", "doc": "port for jmx"}
> {"name": "endpoints", "type": "array", "items": "string", "doc":
> "endpoints supported by the broker"}
> {"name": "rack", "type": "string", "doc": "Rack of the broker.
> Optional. This will be used in rack aware replication assignment for fault
> tolerance."}
> ]
> }
>
> when I check my broker data in zookeeper (which has a non-null broker.rack
> setting in the properties file), I have the following;
>
> {"endpoints":["PLAINTEXT://x.x.x.x.abcd:9092"],"jmx_port":-1
> ,"host":"x.x.x.x.abc","timestamp":"1537527988341","port":9092,"version":2}
>
> there is no 'rack'.
>
> In the server.log file on my kafka broker I see;
> ----
> [2018-09-21 13:00:40,227] INFO KafkaConfig values:
> advertised.host.name = null
> .
> .
> broker.id = 1234567
> broker.rack = rack1
> compression.type = producer
> .
> -----
>
> so it looks fine from the broker side. However, when I restart kafka on
> the host, it doesn't load any rack information into zookeeper.
>
> Can someone please confirm to me, if I have rack awareness, should I
> expect to see a value for 'rack' in zookeeper? If so, do I need to do
> something else on the broker side to get it to include it as part of the
> meta-data it writes (as far as I can see it writes the metadata each time
> kafka is restarted).
>
> thanks
> Bryan
>
>
>
>
>
>
>
>
> On 20/09/2018 11:31, Bryan Duggan wrote:
>
>>
>> Hi,
>>
>> I have a kafka cluster consisting of 3 brokers across 3 different AWS
>> availability zones. It hosts several topics, each of which has a
>> replication factor of 3. The cluster is currently not 'rack-aware'.
>>
>> I am trying to do the following;
>>
>> - add 3 additional brokers (one in each of the 3 AZs)
>>
>> - make the cluster 'rack-aware'. (ie: create 3 racks on a per-AZ
>> basic, each containing 2 brokers)
>>
>> - reassign the topics with the intention of having 1 replica in each
>> of the 3 racks.
>>
>> To achieve this I've added 'broker.rack' to the properties file for each
>> broker. The rack name is the same as the AZ name each broker is in. I've
>> restarted kafka on all brokers (in case that's required for rack-awareness
>> to take effect).
>>
>> Following restart I've attempted to reassign topics across all 6 brokers
>> by running the following;
>>
>> - ./kafka-reassign-partitions.sh --zookeeper $ZK
>> --topics-to-move-json-file topics-to-move.json --broker-list '1,2,3,4,5,6'
>>
>> (where topics-to-move.json is a simple json file containing the topics to
>> reassign)
>>
>> The problem I am having is, after running 'kafka-reassign-partitions.sh'
>> with 6 brokers listed in the broker-list, it doesn't honour
>> rack-awareness, and instead assigns 2 partitions to brokers in a single
>> rack with a 3rd being assigned elsewhere.
>>
>> The version of kafka I am using is 2.11-1.1.1.
>>
>> Any documentation I've read suggests the above should have achieved what
>> I want. However, it is not working as expected.
>>
>> Has anyone else make their kafka cluster 'rack-aware'? If so, did you
>> experience any issues doing so?
>>
>> Or, can anyone tell me if there's some step I'm missing to make this work.
>>
>> TIA
>>
>> Bryan
>>
>>
>>
>>
>
Re: Problems trying to make kafka 'rack-aware'
Posted by Bryan Duggan <br...@boxever.com>.
I didn't get a response to this, but I've been investigating more and
can now frame the problem slightly differently (hopefully, more
accurately).
According to this document
https://cwiki.apache.org/confluence/display/KAFKA/Kafka+data+structures+in+Zookeeper
Which defines broker data structures in zookeeper, the following is the
broker schema (from version 0.10 onwards - I am using version 0.11)
{ "fields":
[ {"name": "version", "type": "int", "doc": "version id"},
{"name": "host", "type": "string", "doc": "ip address or host
name of the broker"},
{"name": "port", "type": "int", "doc": "port of the broker"},
{"name": "jmx_port", "type": "int", "doc": "port for jmx"}
{"name": "endpoints", "type": "array", "items": "string", "doc":
"endpoints supported by the broker"}
{"name": "rack", "type": "string", "doc": "Rack of the broker.
Optional. This will be used in rack aware replication assignment for
fault tolerance."}
]
}
when I check my broker data in zookeeper (which has a non-null
broker.rack setting in the properties file), I have the following;
{"endpoints":["PLAINTEXT://x.x.x.x.abcd:9092"],"jmx_port":-1,"host":"x.x.x.x.abc","timestamp":"1537527988341","port":9092,"version":2}
there is no 'rack'.
In the server.log file on my kafka broker I see;
----
[2018-09-21 13:00:40,227] INFO KafkaConfig values:
advertised.host.name = null
.
.
broker.id = 1234567
broker.rack = rack1
compression.type = producer
.
-----
so it looks fine from the broker side. However, when I restart kafka on
the host, it doesn't load any rack information into zookeeper.
Can someone please confirm to me, if I have rack awareness, should I
expect to see a value for 'rack' in zookeeper? If so, do I need to do
something else on the broker side to get it to include it as part of the
meta-data it writes (as far as I can see it writes the metadata each
time kafka is restarted).
thanks
Bryan
On 20/09/2018 11:31, Bryan Duggan wrote:
>
> Hi,
>
> I have a kafka cluster consisting of 3 brokers across 3 different AWS
> availability zones. It hosts several topics, each of which has a
> replication factor of 3. The cluster is currently not 'rack-aware'.
>
> I am trying to do the following;
>
> - add 3 additional brokers (one in each of the 3 AZs)
>
> - make the cluster 'rack-aware'. (ie: create 3 racks on a per-AZ
> basic, each containing 2 brokers)
>
> - reassign the topics with the intention of having 1 replica in
> each of the 3 racks.
>
> To achieve this I've added 'broker.rack' to the properties file for
> each broker. The rack name is the same as the AZ name each broker is
> in. I've restarted kafka on all brokers (in case that's required for
> rack-awareness to take effect).
>
> Following restart I've attempted to reassign topics across all 6
> brokers by running the following;
>
> - ./kafka-reassign-partitions.sh --zookeeper $ZK
> --topics-to-move-json-file topics-to-move.json --broker-list '1,2,3,4,5,6'
>
> (where topics-to-move.json is a simple json file containing the topics
> to reassign)
>
> The problem I am having is, after running
> 'kafka-reassign-partitions.sh' with 6 brokers listed in the
> broker-list, it doesn't honour rack-awareness, and instead assigns 2
> partitions to brokers in a single rack with a 3rd being assigned
> elsewhere.
>
> The version of kafka I am using is 2.11-1.1.1.
>
> Any documentation I've read suggests the above should have achieved
> what I want. However, it is not working as expected.
>
> Has anyone else make their kafka cluster 'rack-aware'? If so, did you
> experience any issues doing so?
>
> Or, can anyone tell me if there's some step I'm missing to make this work.
>
> TIA
>
> Bryan
>
>
>