Best practice for external DB

So I setup k3s with the internal DB and I was quite happy with it. After going through the course, I am now trying to get k3s into HA mode through the use of an external Postgres DB.

For anyone that has done this setup, what is the best practice for this external DB? Can I set this inside the K3s cluster once it is up and running or do I have to just put it into a containerd and not have it hosted inside a Kubernetes cluster?

Any help would be appreciated!

Thanks everyone!