zookeeper-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Michael Han <h...@cloudera.com>
Subject Re: four letter commands not working as expected.
Date Wed, 30 Nov 2016 18:52:16 GMT
'ruok' is the very basic sanity check of the ZooKeeper server process - it
will return ok as long as the server process is up and reachable through
network (in fact, the server does not nothing but immediately return ok
upon receives 'ruok' request).
'ruup' does seem a better naming semantically to me.

On Tue, Nov 29, 2016 at 5:10 PM, Ben Sherman <bensherman@gmail.com> wrote:

> I expect if none of the 4 letter commands except ruok give a response, then
> the server is definitively not okay.  ruup vs ruok maybe? We see the server
> popping into a looking state quite often, and it's the cause of 100% of our
> outages involving zookeeper.  This isn't an initial state, it's down until
> a restart.
>
> On Tue, Nov 29, 2016 at 3:08 PM, Flavio Junqueira <fpj@apache.org> wrote:
>
> > It looks like the server is in the LOOKING state, so it is not serving
> > request but it is up. I'd say that ruok should return imok as long as the
> > server is up, it's not necessarily a health check.  We could review the
> > semantics of the commands if this behavior and others are confusing.
> >
> > -Flavio
> >
> >
> > > On 29 Nov 2016, at 19:54, Ben Sherman <bensherman@gmail.com> wrote:
> > >
> > > Four letter word ruok is returning imok when the server is decidedly
> not
> > > okay - is this the expected behavior?
> > >
> > > bsherman@zk1:~$ nc localhost 2181 <<< mntr
> > > This ZooKeeper instance is not currently serving requests
> > > bsherman@zk1:~$ nc localhost 2181 <<< ruok
> > > imok
> > >
> > > I'm running 3.4.9.
> > >
> > > --ben
> >
> >
>



-- 
Cheers
Michael.

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message