I think it is more useful to replace it with Extension:MapSources (NB: Capital S, Extension:Mapsources is mine and similar, but different). That is already deployed on the WMF cluster for Wikivoyage.

This extension effectively already is Geohack's code wrapped in a MediaWiki extension. It needs some updates and maybe enhancing to support the features that have been added to Geohack since, but IMHO the way to proceed on this matter.

I'll note that wdq-mm / ORES didn't do too badly during the big bad NFS outage. Those are puppetized, have monitoring, and do not depend on NFS in any form or way. We can do that for geohack too if necessary.