Audit production usage of Loki

The initiative to rollout Loki more widely at GitLab was paused for the reasons described in &1037:

We have agreed that we should pause the Loki effort until we have a better understanding of overall team priorities. There are lots of moving parts at the moment, and it seems our biggest immediate focus should be on improving the stability of our monitoring stack. It doesn't make sense to just have 1 person working on the Loki effort, neither can we justify ramping up investment right now. That doesn't mean we won't come back to it. But we need to better understand how it fits in longer term.

However, Loki is already being used in production by a small number of teams/services:

• License DB
• GitalyCtl
• Product Analytics
• Ops?
• Others?

We should perform an audit to better understand where Loki is currently being used and how it is configured. From this, we can determine next steps (e.g. leave it alone, move to Elastic etc). If we decide to keep Loki in place there might be some work to finish in &1037 and &1165 to ensure its usage is properly monitored and documented.

Note: This issue has nothing to do with the long term direction for Loki. It is merely about ensuring our current situation is well understood.