Deploy PostgreSQL 14 by default

[balasankarc]

Pulp is moving to Django 5, which, starting with version 5.2 requires PostgreSQL 14 or above. Pulp Operator should switch to deploying PG 14 by default.

[balasankarc]

We will probably need to take care of data migration between versions. 🤔

[balasankarc]

We will probably need to take care of data migration between versions.

@git-hyagi On thinking more, I kinda change my opinion. Handling data migration is not a trivial task, and not something I think we should take on. We should rather do this as a breaking change and release 2.0.0, and document how the users can migrate their data to PG 14 before upgrading to 2.0.0. Since we expose the PG image as a configurable setting, users can be ready and already be on PG 14 before upgrading to Pulp Operator 2.0.0.

If users didn't upgrade to PG 14 and upgrade to Operator 2.0.0, the worst that happens in PG refusing to start since the data directory is from an older version. There will be no data loss.

[fleaz]

Just my two cents: PG14 is currently the oldest still supported version of Postgres and will go EOL in a few months. Maybe use this breaking change, and directly go to a more modern PG version. Otherwise you will face the same problem again, in less than a year.

[balasankarc]

To unbreak CI, I have #1597 open. Since PG 14 is the lowest version supported by Django 5, I used that. But the default one should be PG 15+, like mentioned in the above comment, since PG 14 is EOL soon.