Consul MAJOR Upgrade

We’re running a Consul setup on an incredibly old version, 0.8. Due to some tight coupling it makes it challenging to upgrade Consul agents on top of the existing setup, mainly can’t afford any downtime and just the complexity of changes is pretty high. We want to upgrade the entire infrastructure to the latest.

Was thinking to launch a Consul server cluster separate to existing setup, and a second agent to all of our nodes.

Is there any way to run parallel agent setup on all of the nodes to connect to two separate Consul clusters? Haven’t seen any information on how to set this up. Any help would be great.

Figured the advantage of this is that applications which use client libraries could update their code for changes slowly over time by pointing to the new agent - cluster set up.

This was an incredibly naive approach, it’s much easier to upgrade in place. Server/client compatibility is mostly preserved so you can upgrade them independently which is really nice and much more easily controlled.