Previously, we only enabled metrics when the playbook was installing
Prometheus (as indicated by `prometheus_enabled`).
We are exposing metrics when `matrix_metrics_exposure_enabled` is
toggled to `true` though, but people need to toggle various
`_metrics_enabled` variables to make services actually serve metrics.
No more. If `matrix_metrics_exposure_enabled` is `true`, we'll
automatically enable metrics for all services.
This allows people to not include the `matrix-conduit` or
`matrix-dendrite` roles in their custom playbook (based on our roles)
and still not have the playbook choke on variables from these roles
missing.
For getting rid of the `matrix-synapse` role in a similar way,
more work is likely necessary.
After some checking, it seems like there's `/_synapse/client/oidc`,
but no such thing as `/_synapse/oidc`.
I'm not sure why we've been reverse-proxying these paths for so long
(even in as far back as the `matrix-nginx-proxy` days), but it's time we
put a stop to it.
The OIDC docs have been simplified. There's no need to ask people to
expose the useless `/_synapse/oidc` endpoint. OIDC requires
`/_synapse/client/oidc` and `/_synapse/client` is exposed by default
already.
Traefik also serves an internal entrypoint that all addon services
(bridges, bots, etc.) depend on, so it makes sense to have it be
available early on. It is injected as a systemd `required` dependency
for all services, so it would have been pulled earlier anyway (despite
the priority). Nevertheless, it's better to make the playbook-defined
priotities for services match, so that services are explicitly asked to
start in a more correct order.
With these changes in place now, all "start service" tasks executed by
Ansible cause a "change", indicating that all these services are started
in the correct order and none of them is unintentionally started as a
dependency for another.
The old variables still work. The global lets us avoid
auto-detection logic like we're currently doing for
`matrix_nginx_proxy_proxy_matrix_federation_api_enabled`.
In the future, we'd just be able to reference
`matrix_homeserver_federation_enabled` and know the up-to-date value
regardless of homeserver.
This was meant to serve as an intermediary for services needing to reach
the homeserver. It was used like that for a while in this
`bye-bye-nginx-proxy` branch, but was never actually public.
It has recently been superseded by homeserver-like services injecting
themselves into a new internal Traefik entrypoint
(see `matrix_playbook_internal_matrix_client_api_traefik_entrypoint_*`),
so `matrix-homeserver-proxy` is no longer necessary.
---
This is probably a good moment to share some benchmarks and reasons
for going with the internal Traefik entrypoint as opposed to this nginx
service.
1. (1400 rps) Directly to Synapse (`ab -n 1000 -c 100 http://matrix-synapse:8008/_matrix/client/versions`
2. (~900 rps) Via `matrix-homeserver-proxy` (nginx) proxying to Synapse (`ab -n 1000 -c 100 http://matrix-homeserver-proxy:8008/_matrix/client/versions`)
3. (~1200 rps) Via the new internal entrypoint of Traefik (`matrix-internal-matrix-client-api`) proxying to Synapse (`ab -n 1000 -c 100 http://matrix-traefik:8008/_matrix/client/versions`)
Besides Traefik being quicker for some reason, there are also other
benefits to not having this `matrix-homeserver-proxy` component:
- we can reuse what we have in terms of labels. Services can register a few extra labels on the new Traefik entrypoint
- we don't need services (like `matrix-media-repo`) to inject custom nginx configs into `matrix-homeserver-proxy`. They just need to register labels, like they do already.
- Traefik seems faster than nginx on this benchmark for some reason, which is a nice bonus
- no need to run one extra container (`matrix-homeserver-proxy`) and execute one extra Ansible role
- no need to maintain a setup where some people run the `matrix-homeserver-proxy` component (because they have route-stealing services like `matrix-media-repo` enabled) and others run an optimized setup without this component and everything needs to be rewired to talk to the homeserver directly. Now, everyone can go through Traefik and we can all run an identical setup
Downsides of the new Traefik entrypoint setup are that:
- all addon services that need to talk to the homeserver now depend on Traefik
- people running their own Traefik setup will be inconvenienced - they
need to manage one additional entrypoint
We'd be adding integration with an internal Traefik entrypoint
(`matrix_playbook_internal_matrix_client_api_traefik_entrypoint`),
so renaming helps disambiguate things.
There's no need for deperecation tasks, because the old names
have only been part of this `bye-bye-nginx-proxy` branch and not used by
anyone publicly.
This is a bit of a compatibility break.
The role was defaulting the Postgres password to `some-password` and we
auto-generate it now.
However, rebuilding both Postgres and this service should unify the
database credentials and the service configs to the new value.
