On multi-node Kubernetes, the default settings on ReadWriteOnce without pod affinity are non-functional

Steps to reproduce the problem

1. Install Mastodon from the Helm chart to a multi-node Kubernetes cluster with an NFS storage class.
2. If the mastodon-web and mastodon-sidekiq-all-queues end up on different nodes, some of them will hang indefinitely on "ContainerCreating".

They are waiting to mount the persistence volumes system and assets. These can only be mounted on a single node at a time.

Expected behaviour

Everything should work on roughly default settings

Actual behaviour

The pods hang in ContainerCreating state in a difficult to understand way.

Detailed description

The default settings are non-functional on multi-node clusters. Either there needs to be a better comment warning to set pod affinities, the default mode should be ReadWriteMany, or there should be a pod affinity defined which puts these two kinds of pods to the same nodes by default.

Specifications

Mastodon: edge
OS: Ubuntu
Kubernetes: MicroK8S
Nodes: 2+

Start by examining the Helm chart's default persistence access mode and pod scheduling settings, then reproduce the install on a multi-node Kubernetes cluster with NFS storage. Determine which default behavior or warning is intended, and verify that the resulting defaults either allow the affected pods to start or clearly guide users to compatible settings.