In T287245 we ran into a couple of issues with references to decommissioned hardware (bast4001, mwmaint1001) lingering in some team-specific documentation and/or individual configurations.

I think we already make a habit of searching and updating wikitech when we decom a host, so I'm not sure if there's anything we need to improve there, but opening this to prompt discussion just in case.

@Aklapper also noted that you wouldn't know from looking at https://wikitech.wikimedia.org/wiki/Help:SSH_Fingerprints/bast4001.wikimedia.org that the host in question is gone, and suggested that we could add {{obsolete}} to that page when decomming, potentially automatically.

Broader perspective: We do a pretty good job of announcing changes to ops@ when they're of broad importance (changes in active bastions, maintenance servers, etc) but that doesn't necessarily help users like T&S who need to log into the maintenance servers but only occasionally, and probably shouldn't need to keep as close an eye on ops@ traffic (90+% of which they don't care about).

In a perfect world, we might be able to engineer things such that T&S and similar users could accomplish their work without having to log into the maintenance servers (via a web UI or some such) -- but that's a long way away, and in the meantime we can probably support their existing workflows better.