Activate gitlab runners metrics

[oussemos]

Give the possibility to activate metrics on gitlab runners

Docs: https://docs.gitlab.com/runner/monitoring/README.html

[drybjed]

First of all, thanks for your PR! However, can you do it against the debops/debops repository? The roles will be exported from there in the future.

You should describe what each variable does as a separate section, that way they are better presented in the documentation.

In this case the Prometheus server connects to the Runners over TCP, correct? Is the traffic secured somehow? Since daemon listens over the network for external connections, that will require configuration for the debops.ferm role to open the port in the firewall. Registering the TCP port in /etc/services database using debops.etc_services role would also be nice.

If you don't plan to add the above features yourself, open an issue instead - I'll get around to it, most likely after the holidays and New Year.

[oussemos]

@drybjed Thank you your work on the debops project too! I'll open a new PR after (or maybe during) the holidays.

[drybjed]

@oussemos You're welcome. :-) By the way, it would be nice if DebOps could set up Prometheus, so that GitLab Runner support for it could be properly tested. The prometheus package is in Debian, so it makes installation much easier. Perhaps you have a Prometheus Ansible role, or you plan to write it?

[oussemos]

@drybjed I used this one https://github.com/cloudalchemy/ansible-prometheus

[drybjed]

@oussemos Since you're interested in Prometheus, there's currently a work in progress PR with Prometheus support for DebOps. You could try it out and help with development. :-)

[oussemos]

@drybjed I'll have a look into it :)