Postgres upgrade fails when running conduit (and possibly dendrite)

[meenzen]

Describe the bug

The postgres upgrade from version 14 to 15 fails when running conduit.

Apparently the upgrade process assumes you're running synapse, so this issue probably also affects installations running dendrite.

TASK [matrix-postgres : ansible.builtin.debug] **************************************************************************
ok: [conduit.meenzen.net] => 
  msg: Upgrading database from docker.io/postgres:14.5-alpine to docker.io/postgres:15.0-alpine

TASK [matrix-postgres : Ensure matrix-synapse is stopped] ***************************************************************
fatal: [conduit.meenzen.net]: FAILED! => changed=false 
  msg: 'Could not find the requested service matrix-synapse: host'

PLAY RECAP **************************************************************************************************************
conduit.meenzen.net        : ok=21   changed=0    unreachable=0    failed=1    skipped=23   rescued=0    ignored=0 

To Reproduce

You will need an installation which is running an older postgres version, I don't know how to set that up.

Configure the playbook to use conduit:

matrix_homeserver_implementation: conduit

Run the upgrade-postgres tasks:

ansible-playbook -i inventory/hosts setup.yml --tags=upgrade-postgres

Expected behavior

You should be able to upgrade postgres on any server implementation.