[pgpool-general: 8915] Re: Delegate IP on a single node cluster

[Steeve Boulanger]

Hello Bo,

Sorry for the late reply, but after doing some testing, this works
exactly as we needed. Thanks so much for the feedback!

Regards,
Steeve


On Wed, Jul 26, 2023 at 12:00 AM Bo Peng <pengbo at sraoss.co.jp> wrote:

> Hi,
>
> If you are using Pgpool-II 4.3 or later, you can use
> "dynamic cluster membership" to remove the DOWN node from the cluster
> to ensure the cluster has quorum and VIP is available.
>
> [dynamic cluster membership]
>
> https://www.pgpool.net/docs/latest/en/html/runtime-watchdog-config.html#CONFIG-WATCHDOG-CLUSTER-MEMBERSHIP
>
> However, using the dynamic cluster membership has an associated risk of
> causing a split-brain. So it is strongly recommended to carefully review
> if the setup requires the dynamic cluster membership and consider using
> conservative values for related settings.
>
> On Tue, 25 Jul 2023 21:35:41 -0600
> Steeve Boulanger <sboulanger29 at gmail.com> wrote:
>
> > Greetings,
> >
> > We recently had a scenario where 2 nodes out of 3 became unavailable, and
> > we were left with a single node (Primary). As a result, the delegate IP
> was
> > not assigned to the Leader /Primary node due to loss of quorum (from my
> > understanding). Since all our applications are configured to use the
> > delegate IP, we experience an unplanned outage.
> >
> > My question is: is there a way to avoid an outage in this specific case?
> ie
> > only a single node available? Or in other words, is it possible to have
> > pgpool assign the delegate IP, even when it doesn't have a quorum?
> >
> > Regards,
> > Steeve
>
>
> --
> Bo Peng <pengbo at sraoss.co.jp>
> SRA OSS LLC
> TEL: 03-5979-2701 FAX: 03-5979-2702
> URL: https://www.sraoss.co.jp/
>
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