[pgpool-general: 7648] Re: Why isn't watchdog required on Kubernetes?

[Bo Peng]

> 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) 

-- 
Bo Peng <pengbo at sraoss.co.jp>
SRA OSS, Inc. Japan
http://www.sraoss.co.jp/