CSI volume mount option updates while volume in use

[ygersie]

Hey there,

Currently Nomad doesn't allow updating a volume registration's mount options while the volume is in use. Is there a specific reason for this?

Ideally I'd like to be able to update mount options on a volume registration and restart the alloc to pick up those changes. This is especially important when using Nomad's Terraform provider to manage volumes.

[tgross]

Hi @ygersie! I did some digging and discovered the behavior dates all the way back to #12167 but there's no explanation as to why (and I don't remember, tbh). A quick look at the current RPC code suggests this should be safe to do; there's no CSI RPC sent to the plugins for a state update unless we try to expand the volume, and those requests can't even see mount options.

I'll mark this for the roadmap.