This commit introduces a new role that downloads and installs the
prometheus community postgres exporter https://github.com/prometheus-community/postgres_exporter.
A new credential is added to matrix_postgres_additional_databases that
allows the exporter access to the database to gather statistics.
A new dashboard was added to the grafana role, with some refactoring
to enable the dashboard only if the new role is enabled.
I've included some basic instructions for how to enable the role in
the Docs section.
In terms of testing, I've tested enabling the role, and disabling
it to make sure it cleans up the container and systemd role.
Expected to have regressed after https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1008
This patch comes with its own downsides (as described in the comments
for matrix_prometheus_node_exporter_container_http_host_bind_port),
but at least there's:
- no security issue
- metrics remain readable from matrix-prometheus (even if the network metrics are inaccurate)
A better patch is certainly welcome.
Basic system stats, to show stuff the synapse metrics
can't show such as resource usage by bridges, etc
Seems to work fine as well.
This too has only been tested on debian amd64 so far
