[FEATURE] RWX volume supports different NFS version (4.2) and mount options

[derekbit]

Is your feature request related to a problem? Please describe (👍 if you like this request)

Currently, RWX volume is based on NFS v4.1 protocol. Some new features such as sparse files, file pre-allocation, server-side clone and copy and application data block (ADB) are introduced in v4.2.
The feature request aims to support both v4.1 and 4.2 as well as customized mount options.

Describe the solution you'd like

Describe alternatives you've considered

Additional context

cc @james-munson

[james-munson]

Varying the mount options is already an option, simply by using nfsOptions="vers=4.2,hard,etc..." in the parameters for the volume's storage class.

This seems as simple as changing the defaultOptions to use "vers=4.2" in csi/node_server.go".

Note that there is still the possibility of overriding with 4.1 in the nfsOptions if desired.

Note also that NFS backupstore, if not overridden in the settings, uses a default of nfs4.2 already, with fallback attempts at 4.1 and 4.0 if unsuccessful. But there is no such fallback path for RWX volume mounts.

[derekbit]

I see. Can you help update the RWX doc https://longhorn.io/docs/1.6.0/advanced-resources/rwx-workloads/ for the mount options? Thank you.

[james-munson]

Base ticket for the feature change to NFS mounts for RWX volumes is #6655

I'll look over the docs as well. I see some of that was addressed in longhorn/website#777

[james-munson]

I created #7716 to cover the docs improvement, so this can be expedited on its own.

[longhorn-io-github-bot]

Pre Ready-For-Testing Checklist

• Where is the reproduce steps/test steps documented?
  The reproduce steps/test steps are at: n/a

• Is there a workaround for the issue? If so, where is it documented?
  The workaround is at: n/a

• Does the PR include the explanation for the fix or the feature? Yes

• Does the PR include deployment change (YAML/Chart)? If so, where are the PRs for both YAML file and Chart?
  The PR for the YAML change is at: n/a
  The PR for the chart change is at: n/a

• Have the backend code been merged (Manager, Engine, Instance Manager, BackupStore etc) (including backport-needed/*)?
  The PR is at: n/a

• Which areas/issues this PR might have potential impacts on?
  Area: RWX volumes
  Issues

• If labeled: require/LEP Has the Longhorn Enhancement Proposal PR submitted?
  The LEP PR is at: n/a, override for mount options already exists, this just changes the default NFS version.

• If labeled: area/ui Has the UI issue filed or ready to be merged (including backport-needed/*)?
  The UI issue/PR is at: n/a

• If labeled: require/doc Has the necessary document PR submitted or merged (including backport-needed/*)?
  The documentation issue/PR is at: Tracked by separate ticket https://github/longhorn/longhorn/issues/7716

• If labeled: require/automation-e2e Has the end-to-end test plan been merged? Have QAs agreed on the automation test case? If only test case skeleton w/o implementation, have you created an implementation issue (including backport-needed/*)
  The automation skeleton PR is at: n/a
  The automation test case PR is at: n/a
  The issue of automation test case implementation is at (please create by the template)

• If labeled: require/automation-engine Has the engine integration test been merged (including backport-needed/*)?
  The engine automation PR is at: n/a

• If labeled: require/manual-test-plan Has the manual test plan been documented?
  The updated manual test plan is at

• If the fix introduces the code for backward compatibility Has a separate issue been filed with the label release/obsolete-compatibility?
  The compatibility issue is filed at: n/a

[james-munson]

This is reasonable to backport. All current releases use nfs-ganesha that supports v4.2.

[derekbit]

@james-munson
Can you test v4.2 by a different StorageClass as well in tests? Thank you.

https://github.com/longhorn/longhorn-tests/blob/master/manager/integration/tests/test_rwx.py

[james-munson]

I do not understand what is being asked for here. Guessing that it is to add regression test cases with specific overrides.

[derekbit]

I do not understand what is being asked for here. Guessing that it is to add regression test cases with specific overrides.

If you check https://github.com/longhorn/longhorn-tests/blob/master/manager/integration/tests/test_rwx.py, you can find it only test NFS v4.1. You can add test v4.2 as well by a StorageClass with different mount options.

[innobead]

@james-munson Please do what @derekbit suggested. Need to have e2e tests in 4.2 as well.

[james-munson]

In fact, it now tests 4.2 when run on 1.6.x, master, or any release for which 4.2 is the default. But I take your point that there should be some test cases that test nfsOptions overrides explicitly, for non-default NFS versions.

Assigning #7639 to myself.

[james-munson]

This issue has been superseded by #7741 which reverts the default to vers=4.1. It can be closed when that one is committed.