Finally managed to replace two VMs with a single VM.
Yay!
This gives me a service discovery layer (Consul), moves the scheduler Sidekiq job off of the www node, and provides a platform for various background jobs to run automatically.
Now I can move www to an autoscale group.
Follow
though I think I'll upgrade redis/elasticsearch and postgres first, so they're wired into the service discovery plane
so I guess Postgres is next on the list of "things to upgrade"
also I have to do major postgres version upgrades, so there'll be a Significant Downtime when I do that