Add initial monitoring server configuration

[joinemm]

Adds monitoring VM running Grafana and Prometheus, that monitors build4 and binarycache using node_exporter metrics

[henrirosten]

Approved, but I have not tested this.
@joinemm :
I assume you get a warning on installing the new monitoring configuration, since it doesn't have secrets.yaml, so the host key decryption should fail:

ghaf-infra/tasks.py

Line 277 in 6831845

subprocess.run(

[joinemm]

@henrirosten I actually never saw this warning when testing, I was not aware secrets were required

[henrirosten]

@henrirosten I actually never saw this warning when testing, I was not aware secrets were required

It's strictly not required, but if there's no ssh_host_ed25519_key for the given nixosconfig, install task should issue a warning and ask confirmation from the user. If that's not what happens, then it's probably an error in tasks.py.

[joinemm]

added secrets and tested with install task

[henrirosten]

You are missing a license for the new secrets.yaml, you should add secrets.yaml.license similarly to other host configs:

WARNING 'reuse lint':
MISSING COPYRIGHT AND LICENSING INFORMATION

The following files have no copyright and licensing information:

• hosts/monitoring/secrets.yaml