I'm still looking for a very simple system that would let me do a live redeploy with a blocking database schema migration in between.

For that I (think I)'d need a system that will:

* start off with X nodes live in the load balancer

* trigger redeploys on half (or so) of them

* when half of the nodes have been redeployed, block and perform the database migration and trigger redeploys for the remaining server

* after the migration completed switch over the load balancer to the now updated half of servers

Is this something that you could orchestrate with Serf? Or am I looking in the wrong direction here.