Add monitoring to alert when Gitlab project pre-caching (pre-clone) is falling behind
Reference: production#2114 (comment 341201987)
The gitlab project uses a clone cache to help make sure that CI jobs are not over-loading the project gitaly node with deep clones. If that clone cache is too old, or has not run recently, it can cause a lot of git-upload-pack calls that can take a long time.
If we do decide to monitor this, we should create a runbook with clear actions that can be taken to remediate or fix the situation.
Edited by Alberto Ramos