foreman-documentation Add PostgreSQL space requirement in prerequisites

As PostgreSQL is upgraded from 12 to 13 during the upgrade process, it is necessary to maintain enough space for this. Adding this as a prerequisite to the upgrade.

Ref: https://github.com/theforeman/foreman_maintain/blob/master/definitions/checks/disk/available_space_postgresql13.rb

JIRA: https://issues.redhat.com/browse/SAT-28667

What changes are you introducing?

Why are you introducing these changes? (Explanation, links to references, issues, etc.)

Anything else to add? (Considerations, potential downsides, alternative solutions you have explored, etc.)

Checklists

[x] I am okay with my commits getting squashed when you merge this PR.
[X] I am familiar with the contributing guidelines.

Please cherry-pick my commits into:

[X] Foreman 3.12/Katello 4.14 (Satellite 6.16)
[ ] Foreman 3.11/Katello 4.13
[ ] Foreman 3.10/Katello 4.12
[ ] Foreman 3.9/Katello 4.11 (Satellite 6.15; orcharhino 6.8/6.9/6.10)
[ ] Foreman 3.8/Katello 4.10
[ ] Foreman 3.7/Katello 4.9 (Satellite 6.14)
[ ] Foreman 3.6/Katello 4.8
[ ] Foreman 3.5/Katello 4.7 (Satellite 6.13; orcharhino 6.6/6.7)
We do not accept PRs for Foreman older than 3.5.

Oct 08 '24 08:10 AkshayGadhaveRH

The PR preview for 5ad1024b0375ac8a2a9fa742f2112c366b928b5b is available at theforeman-foreman-documentation-preview-pr-3357.surge.sh

The following output files are affected by this PR:

show diff

show diff as HTML

Oct 08 '24 08:10 github-actions[bot]

Looking at the comment in https://github.com/theforeman/foreman-documentation/pull/3357/files/ae505f817e93a84552f4538c87ef59d7aad4e133#r1792231647, I think Ashish might have simply misread the line but to be fair, "same amount" and "some amount" are very similar and this could happen to users too.

While the new bullet point explains the actual requirement, it doesn't explain the context. (What PostgreSQL upgrade? Why does PostgreSQL need upgrading? When does it happen? Should I be the one to perform the upgrade?) I'm not suggesting that all these questions need to be answered -- that would be too many words for a simple prerequisite. But adding just a little bit more detail about what is happening during the upgrade would help prevent users from asking these questions in the first place.

More importantly, the related release notes (upstream and downstream) mention that users can delete /var/lib/pgsql/data-old/ after the upgrade completes. If this is valid, then I'd recommend including it as a step in the upgrade procedure.

Oct 09 '24 11:10 aneta-petrova

@AkshayGadhaveRH Rebasing should fix the Vale problem.

Oct 16 '24 11:10 apinnick

Cherry picked:

c5fa1d4ca1..cf5909c951 3.12 -> 3.12
b51c68b0a0..e3425d7bf5 3.11 -> 3.11

Oct 16 '24 19:10 Lennonka