Remove PgBouncer standalone installation

[atsikham]

Is your feature request related to a problem? Please describe.
We say in documentation that PgBouncer standalone installation is deprecated and will be removed.

Describe the solution you'd like

1. Remove ability to specify this setting in configuration, modify schema
2. Clean up Ansible configuration
3. Update documentation

Describe alternatives you've considered

Additional context

---

DoD checklist

• Changelog updated
• COMPONENTS.md updated / doesn't need to be updated
• Schema updated / doesn't need to be updated
• Feature has automated tests
• Automated tests passed (QA pipelines)
  • apply
  • upgrade
• Idempotency tested
• Documentation added / updated / doesn't need to be updated
• All conversations in PR resolved
• Solution meets requirements and is done according to design doc
• Usage compliant with license
• Backport tasks created / doesn't need to be backported

[mkyc]

Lets remember about very clear change log entry.

[rafzei]

It's clear for me, links:

Defaults:
https://github.com/epiphany-platform/epiphany/blob/e64dd05451d6d81ff4322ab6f2319353d0579e0b/schema/common/defaults/configuration/postgresql.yml#L90-L91

Schema:
https://github.com/epiphany-platform/epiphany/blob/e64dd05451d6d81ff4322ab6f2319353d0579e0b/schema/common/validation/configuration/postgresql.yml#L71-L75

Role:
https://github.com/epiphany-platform/epiphany/tree/develop/ansible/playbooks/roles/postgresql

Docs:
https://github.com/epiphany-platform/epiphany/blob/develop/docs/home/howto/DATABASES.md#how-to-set-up-postgresql-connection-pooling

[to-bar]

pgBouncer causes the following error when installing on Ubuntu 20.04 (Azure & AWS) on Extensions | PgBouncer | Restart systemd service task:

Dec  2 18:21:02 ci-devazurubuflannel-postgresql-vm-0 systemd[1]: Stopping LSB: start pgbouncer...
Dec  2 18:21:02 ci-devazurubuflannel-postgresql-vm-0 pgbouncer[25630]:  * Stopping PgBouncer pgbouncer
Dec  2 18:21:02 ci-devazurubuflannel-postgresql-vm-0 pgbouncer[25634]: start-stop-daemon: matching only on non-root pidfile /var/run/postgresql/pgbouncer.pid is insecure
Dec  2 18:21:02 ci-devazurubuflannel-postgresql-vm-0 pgbouncer[25630]:    ...fail!
Dec  2 18:21:02 ci-devazurubuflannel-postgresql-vm-0 systemd[1]: pgbouncer.service: Control process exited, code=exited, status=2/INVALIDARGUMENT
Dec  2 18:21:02 ci-devazurubuflannel-postgresql-vm-0 systemd[1]: pgbouncer.service: Failed with result 'exit-code'.
Dec  2 18:21:02 ci-devazurubuflannel-postgresql-vm-0 systemd[1]: Stopped LSB: start pgbouncer.
Dec  2 18:21:02 ci-devazurubuflannel-postgresql-vm-0 systemd[1]: pgbouncer.service: Found left-over process 24592 (pgbouncer) in control group while starting unit. Ignoring.
Dec  2 18:21:02 ci-devazurubuflannel-postgresql-vm-0 systemd[1]: Starting LSB: start pgbouncer...
Dec  2 18:21:02 ci-devazurubuflannel-postgresql-vm-0 pgbouncer[25635]:  * Starting PgBouncer pgbouncer
Dec  2 18:21:02 ci-devazurubuflannel-postgresql-vm-0 pgbouncer[25635]:    ...fail!
Dec  2 18:21:02 ci-devazurubuflannel-postgresql-vm-0 systemd[1]: pgbouncer.service: Control process exited, code=exited, status=2/INVALIDARGUMENT
Dec  2 18:21:02 ci-devazurubuflannel-postgresql-vm-0 systemd[1]: pgbouncer.service: Failed with result 'exit-code'.
Dec  2 18:21:02 ci-devazurubuflannel-postgresql-vm-0 systemd[1]: Failed to start LSB: start pgbouncer.

hence this task will be done before #1331.

[przemyslavic]

Looks like everything still works fine without pgbouncer 🐗