Explore / install a varnish prometheus probe

To have some bits on the real-time traffic on the web app.

eg. https://github.com/jonnenauha/prometheus_varnish_exporter

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Migrated from T2733 (view on Phabricator)

added Metrics/monitoring System administration priority:High labels

The varnish logs should be also ingested to elasticsearch to have fine grained statistics.

It seems there is not filebeat / journalbeat supported module, but it may be possible to use a combinaison of varnishncsa [1] to generate varnish logs and filebeat to ingest them. It could also allow to have statistics on the caching effectiveness per requests.

• [1] https://varnish-cache.org/docs/4.0/reference/varnishncsa.html

added state:wip label

the exporter is deployed. The varnish stats are available on this dashboard: https://grafana.softwareheritage.org/d/pE2xMZank/varnish

removed state:wip label

closed