Now that I have working #NFS in #Kubernetes, can I point multiple instances of #Postfix at the queues for high availability? Nope.

Postfix file locking and NFS

For the Postfix mail queue, it does not matter how well NFS file locking works. The reason is that you cannot share Postfix queues among multiple running Postfix instances. You can use NFS to switch a Postfix mail queue from one NFS client to another one, but only one NFS client can access a Postfix mail queue at any particular point in time.

But I can create multiple instances of Postfix, each with its own queues, using StatefulSets. But I don’t think it buys me very much in terms of reliability; with my workload, a few seconds of downtime while k3s spins up a new Postfix pod isn’t very impactful.