Document Production Gitlab Values and Recommendations

As a result of the findings from the recent updates for Gitlab to 14.3, callout and document recommendations for production Gitlab deployed with BigBang.

Specific callouts are:

• Large Gitlab installations should up their addons.gitlab.flux.timeout value (default is 10m) but should be increased to around 30-45m & their addons.gitlab.flux.upgrade.retries form the default of 3 to a number closer to 8-10.
• resource requests/limits for webservice and gitaly workloads should be increased over BigBang and package defaults. Recommendations are:
  • webservice:

    cpu: 2
    memory: "4Gi"

  • gitaly:

    cpu: 2
    memory: "4Gi"

• Also document that Gitlab engineers state predicting Gitaly's resource consumption is very difficult, and will require testing to find the applicable limits/requests for each individual installation. See this Epic Gitlab is working on to address this.

Best destination for these additions is docs/production.md?