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From Patrick Hunt <ph...@apache.org>
Subject Re: Healthcheck using the stat command
Date Wed, 25 Jan 2012 23:32:57 GMT
Prefer "srvr" over "stat" in most cases - stat returns details on the
connections which you probably don't need. (and adds unnecessary load
on the server)

Also look at mntr in 3.4+

Patrick

On Mon, Jan 23, 2012 at 8:29 PM, Camille Fournier <camille@apache.org> wrote:
> If the node is "leader", "follower" or "observer" you are ok. That's all
> you should need to look for. ruok just checks to see if the port is
> responding and the code is running, pretty much. stat will actually look at
> the system and see if the zkserver has started. If so, you'll get some
> info, if not, you'll see
> "This ZooKeeper instance is not currently serving requests"
>
> C
>
> On Mon, Jan 23, 2012 at 11:24 PM, Jonathan Simms <slyphon@gmail.com> wrote:
>
>> On Mon, Jan 23, 2012 at 5:16 PM, Jordan Zimmerman
>> <jzimmerman@netflix.com> wrote:
>> > The problem with 'ruok' is that it doesn't tell you the state of the
>> > Instance. 'ruok' might return 'imok' but the instance might not be
>> serving
>> > due to some other error. Only a 'stat' will tell you that.
>> >
>> > -JZ
>> >
>>
>> Can you provide an example of what that would look like? A high
>> Outstanding count? A Mode that's not "leader", "follower", or
>> "observer"?
>>
>> -J
>>
>>
>> > On 1/23/12 1:51 PM, "Philip Smith" <philip_smith@apple.com> wrote:
>> >
>> >>There is a batch java program that does a health check:
>> >>
>> >>validateZookeeperService.validateZookeeperService()
>> >>
>> >>
>> >>which basically runs the ruok command. You could run the stat command and
>> >>parse out the response but I think 99% of what you want could be simply
>> >>looking for 'imok' in the response to the ruok command.
>> >>
>> >>philip_smith@st11p00td-devlog001:~ 2 $ alias zkok
>> >>alias zkok='for idx in 1 2 3 4 5 ; do export
>> >>zkserver="st11p00td-zookeeper00${idx}" ; echo "$zkserver $( echo ruok |
>> >>nc  $zkserver 2181 )" ; done'
>> >>philip_smith@st11p00td-devlog001:~ 3 $ zkok
>> >>st11p00td-zookeeper001 imok
>> >>st11p00td-zookeeper002 imok
>> >>st11p00td-zookeeper003 imok
>> >>st11p00td-zookeeper004 imok
>> >>st11p00td-zookeeper005 imok
>> >>philip_smith@st11p00td-devlog001:~ 4 $
>> >>
>> >>
>> >>On Jan 23, 2012, at 1:45 PM, Natarajan Suresh wrote:
>> >>
>> >>> I am trying to write a small health check script for the zookeeper
>> >>>instances. The "stat" command gives me an output like this:
>> >>> ===========================Zookeeper version: 3.3.3-1073969, built on
>> >>>02/23/2011 22:27 GMTClients:
>> >>>/127.0.0.1:38929[0](queued=0,recved=1,sent=0)
>> >>>/17.155.7.152:37603[1](queued=0,recved=474752,sent=474752)
>> >>> Latency min/avg/max: 0/0/35Received: 1113675Sent: 1113706Outstanding:
>> >>>0Zxid: 0x2000e2925Mode: followerNode count:
>> 71===========================
>> >>> How do I know that the server is ok ? I do not have a bad instance with
>> >>>me to checkout what the output will be in that case.
>> >>> If anyone has already written a health check script, can you please
>> >>>share with me ?
>> >>> Thanks
>> >>> |Suresh|
>> >>
>> >>
>> >>Regards, Philip
>> >>
>> >>Philip Smith
>> >>Senior Software Engineer
>> >>philip_smith@apple.com
>> >>408 862-1360 office
>> >>530 574-1659 mobile
>> >>
>> >
>>

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