We had checks to avoid stopping/deleting systemd services for workers
that used to exist and will continue to exist, but we were deleting
config files for workers each time.. Only to recreate them again later.
This lead to:
- too many misleading "changed" tasks
- too much unnecessary work
- potential failures during playbook execution possibly leaving the
system in a bad state (no worker config files)
This switches the `docker exec` method of spawning
Synapse workers inside the `matrix-synapse` container with
dedicated containers for each worker.
We also have dedicated systemd services for each worker,
so this are now:
- more consistent with everything else (we don't use systemd
instantiated services anywhere)
- we don't need the "parse systemd instance name into worker name +
port" part
- we don't need to keep track of PIDs manually
- we don't need jq (less depenendencies)
- workers dying would be restarted by systemd correctly, like any other
service
- `docker ps` shows each worker separately and we can observe resource
usage
If we load it at runtime, during matrix-synapse role execution,
it's good enough for matrix-synapse and all roles after that,
but.. it breaks when someone uses `--tags=setup-nginx-proxy` alone.
The downside of including this vars file like this in `setup.yml`
is that the variables contained in it cannot be overriden by the user
(in their inventory's `vars.yml`).
... but it's not like overriding these variables was possible anyway
when including them at runtime.
Many people probably didn't even know this - that ansible can be
quite a bit picky about what it will be willing to work with remotely.
Thanks @maxklenk !
also, worker.yaml.j2:
- hone worker_name
- remove worker_pid_file entry (would only be used if worker_daemonize
set to true; also, synapse only knows about the container namespace
and thus can not provide the required host-view PID)
Slavi Pantaleev
Michael Collins
Marcel Partap