On https://wikitech.wikimedia.org/wiki/Switch_Datacenter#Services there are special instructions for restbase-async:

Restbase is a bit of a special case, and needs an additional step, if we're just switching active traffic over and not simulating a complete failover:

# pool restbase-async everywhere, then depool restbase-async in the newly active dc, so that async traffic is separated from real-users traffic as much as possible.

This special case is problematic, and during today's switchover we decided to leave restbase-async like everything else, only pooled in codfw.

We should either:

• stop treating restbase-async specially and just have it be like any other service, pooled in the active DC
• implement said special handling in the cookbook so it's not an extra step