Looking for shell based elasticsearch client or something similar to curator run in command line

Restart assistance is not likely to be a part of it...

Yeah, that makes sense... sorry for the confusion... I'm not saying to have curator support restart... but just to give assistant to some extent, e.g. give upgrade suggestions based on source and target elasticsearch versions, a bit similar to Upgrade to Elastic 8.11.1 | Elastic Installation and Upgrade Guide [8.11] | Elastic, or show current upgrade status, or auto-adjust shard allocation before and after upgrade, and so on. I was doing that kind of work in my shell script at the moment... but of course, upgrade itself is more complicated that involves manual steps inevitably which doesn't have to be part of curator...

tools to help automate remote reindex are definitely on the table...

That's cool... wonder where I could find it... is there anything documented for this, e.g a github issue or something?