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From rammohan ganapavarapu <rammohanga...@gmail.com>
Subject Re: Zookeeper resolving to old host IP addresses
Date Wed, 22 Jan 2020 17:52:36 GMT
Andor,

Thank you, i will look into dynamic reconfig option.

Ram

On Wed, Jan 22, 2020 at 2:03 AM Andor Molnar <andor@apache.org> wrote:

> Hi Ram,
>
> As far as I can see from the code, ZooKeeper uses the standard Java calls
> getByName() and getAllByName() every time it’s trying to connect to a
> server.
>
> ————————
> // zookeeper.ipReachableTimeout is not defined
> if (ipReachableTimeout <= 0) {
>     address = InetAddress.getByName(this.hostname);
> } else {
>     address = getReachableAddress(this.hostname, ipReachableTimeout);
> }
> ————————
>
> ZK doesn’t (and definitely should not) cache IP addresses. It’s either the
> cache of JVM or your DNS server.
>
> Dynamic reconfig is available in 3.5.x versions which are already stable
> now and I think with that you don’t need to reuse existing hostnames.
> Instead use reconfig commands to properly remove old nodes and add new
> ones. Sounds like more cumbersome, but maybe more reliable.
>
> Andor
>
>
>
>
> > On 2020. Jan 21., at 23:14, rammohan ganapavarapu <
> rammohanganap@gmail.com> wrote:
> >
> > But still happening for me, is there any config on zookeeper side to make
> > this fix to work?
> >
> > Ram
> >
> > On Tue, Jan 21, 2020 at 2:12 PM Michael Han <hanm@apache.org> wrote:
> >
> >> Could be ZOOKEEPER-1506, though this should be fixed already in 3.4.14.
> >>
> >> On Tue, Jan 21, 2020 at 2:01 PM rammohan ganapavarapu <
> >> rammohanganap@gmail.com> wrote:
> >>
> >>> Hi Enrico,
> >>>
> >>> I see same with both 3.4.5 and 3.4.14
> >>>
> >>> Ram
> >>>
> >>> On Tue, Jan 21, 2020 at 1:53 PM Enrico Olivelli <eolivelli@gmail.com>
> >>> wrote:
> >>>
> >>>> Hi,
> >>>> Which version of ZK are you using?
> >>>> Enrico
> >>>>
> >>>>
> >>>> Il mar 21 gen 2020, 22:51 rammohan ganapavarapu <
> >> rammohanganap@gmail.com
> >>>>
> >>>> ha scritto:
> >>>>
> >>>>> Hi,
> >>>>>
> >>>>> Does zookeeper cache the host IP? if so how long does it cache?
I
> >> have
> >>> a
> >>>>> zk cluster in autoscaling groups and when a new node comes up, other
> >>>> nodes
> >>>>> still resolving to old IP. Is there any setting to invalidate dns
> >> cache
> >>>> for
> >>>>> zookeeper? or is it jvm dns cache? until other nodes resolves to
new
> >>> IP,
> >>>>> this node not able to join the cluster.
> >>>>>
> >>>>> Thanks,
> >>>>> Ram
> >>>>>
> >>>>
> >>>
> >>
>
>

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