fix: for k8s set PGDATA to subfolder

[wilmardo]

PGDATA
This optional variable can be used to define another location - like a subdirectory - for the database files. The default is /var/lib/postgresql/data, but if the data volume you're using is a filesystem mountpoint (like with GCE persistent disks), Postgres initdb recommends a subdirectory (for example /var/lib/postgresql/data/pgdata ) be created to contain the data.

Source: https://hub.docker.com/_/postgres/

Since within Kubernetes the persistent disks are filesystem mountpoints the PGDATA variable should be set to a subdir.

This should fix #251 but I have not been able to test it yet.

EDIT:
Just tested this and it works fine but it also works fine without (this is on NFS however so might not be completely representable). @Telokis could you test this?
I am still in favor of merging this since it is advised by Postgres 👍

[Telokis]

Hey @wilmardo !

Thanks for the PR.
I quickly glanced at it. I plan on testing it but shouldn't you use https://kubernetes.io/docs/concepts/storage/volumes/#using-subpath instead of simply moving the mount directory?
Right now it seems like you didn't change the behavior at all but simply changed the mounted directory.

I'll try this ASAP and report here.

EDIT: My bad, I misunderstood subPath. However, I think you should only add the PD_DATA variable without changing the mountPath itself.

[Telokis]

Back with feedback!

Got the exact same error but the directory is different:

2019-11-26 15:05:28.501 UTC [142] FATAL:  data directory "/var/lib/postgresql/data/pgdata" has wrong ownership
2019-11-26 15:05:28.501 UTC [142] HINT:  The server must be started by the user that owns the data directory.

I'm gonna try with the different mountPath to see if it helps but I'm not really hopeful.

EDIT: Just tried the other idea but still no luck. It doesn't want to work.

[wilmardo]

@Telokis Thanks for the test! Good point about the mountPath I restored the values to what they were.

The current approach is what you gave tested and still isn't working?

[Telokis]

Yes, I tried with the current setup (after your modifications) but I also tried with the previous setup.

In both cases, the same error arised.

[wilmardo]

Could you share the values.yml you are using so I could test it?

[Telokis]

I didn't change it at all, I'm using all default values everywhere. It was a simple "clone and run" test