Re: Access a Postgres storage with two independent instances

On Tue, 2024-05-07 at 09:56 +0530, first last wrote:
> Actually what I want is multiple Postgres instances to have read
> and write access to the same data storage directory. Anyway, that
> can not be possible as what you say. But, when I deploy
> MySQL/MongoDB deployment with multiple replicas to access the same
> storage, the all pods except one become CrashLoopBackOff state.
> This is happening for MySQL/Mongo. When it comes to Postgres, I
> deployed it with multiple pods, all the pods became healthy and
> there is no such CrashLoopBackOff state occurred. But those pods
> access different storages for every pod. Why this totally different
> from MySQL and Mongo?

No idea, but this doesn't appear to have anything to do with
PostgreSQL. You could load any image in that container and then see
what the storage looks like. Probably better asked on a kubernetes
list somewhere.

Random thought, though, if you actually have multiple nodes in your
k8s cluster, you might just be seeing an artifact of the
ReadWriteOnce access mode. For a real shared volume you probably want
ReadWriteMany, which only a few storage backends support (and which,
again, PostgreSQL would not work on).