Change Details

Currently, the codfw cache clusters are configured logically as a tier-1 site in parallel with eqiad. This is the ideal state we want to be in for the long haul, with both of the tier-1 sites being options for the backend of the tier-2's, and tier-1 cache->app layer routing/failover being a completely separate decision. However, at present we don't have a good solution for traffic security on the cross-tier-1 cache->app traffic in that scenario (see also: T108580 , T81543#1503321 , T107956 (mostly rejected in favor of the first link at this point, I think)). So, for now, we should reconfigure codfw to be tier-2 as far as the edge layer is concerned, so that we can start using it for traffic while the other bits are still being sorted out.