[pgpool-general: 7651] Re: Why isn't watchdog required on Kubernetes?

Andrew Pashkin andrew.pashkin at gmx.co.uk
Tue Jul 27 23:49:17 JST 2021


Does it mean, that it's safe to run multiple PG Pools on the same
cluster without watchdog mode (so that all of the instances of PGPool
are "active")?

On 26.07.21 05:53, Bo Peng wrote:
>> Hello!
>>
>>> Pgpool-II's health check, automatic failover, Watchdog and online
>>> recovery features aren't required onKubernetes. You need to only
>>> enable load balancing and connection pooling.
>> Says this page:
>> https://www.pgpool.net/docs/latest/en/html/example-kubernetes.html
>> <https://www.pgpool.net/docs/latest/en/html/example-kubernetes.html>
>>
>> How come? Does Kubernetes somehow magically eliminate the problem of
>> having a single point of failure in form of PGPool?
> Pgpool is deployed as "kind: Deployment".
> If pgpool pod goes down, Kubernetes will restart another one.
>
> To completely eliminate downtime, you may increase the number of "replicas".
>
> --------------------
> kind: Deployment
> metadata:
>    name: pgpool
> spec:
>    replicas: 3
> ...
> --------------------
>
> If you are setting more than 1 replicas, you need to configure
> "max_pool", "num_init_children", "max_connections" and
> "superuser_reserved_connections" to satisfy:
>
>     number of Pgpool-II replicas × max_pool × num_init_children <= (max_connections - superuser_reserved_connections)
>


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