Remote builders, in my experience, have no trouble pulling public images from other repositories (like docker hub). What you’re seeing might be an intermittent issue, possibly related to: Unable to deploy new version of app or scale servers - #7 by catflydotio
Yeah, you may want to also speak with u/CanRau to who tried couch on Fly earlier but not sure if they got it working: Can't get a CouchDB Cluster working (connection_closed)