OpenStack: Can't set root-disk-source to use local storage

[Haw Loeung]

Hi,

https://juju.is/docs/olm/constraints#heading--openstack says:

"""
Note: root-disk-source is either “local” or “volume”
"""

But when trying to set to local storage, I get an error about it being unsupported:

| prod-is-external-kubernetes@is-my-bastion-ps5:~$ juju set-constraints kubernetes-worker 'cores=4 mem=16384M root-disk=51200M root-disk-source=local'
| ERROR invalid constraint value: root-disk-source=local
| valid values are: [volume]

| prod-is-external-kubernetes@is-my-bastion-ps5:~$ juju set-model-constraints root-disk-source=local
| ERROR invalid constraint value: root-disk-source=local
| valid values are: [volume]

Model is running Juju 2.9.32. Client I've tried is 2.9.34-ubuntu-amd64 from the snap.

[Paul Collins (pjdc)]

This might be the culprit (https://github.com/juju/juju/blob/develop/provider/openstack/provider.go#L596):

validator.RegisterVocabulary(constraints.RootDiskSource, []string{rootDiskSourceVolume})

I'd guess it should be something like:

validator.RegisterVocabulary(constraints.RootDiskSource, []string{rootDiskSourceLocal, rootDiskSourceVolume})

[Evanson Mwangi (mr-parish)]

https://github.com/juju/juju/pull/14655

[John A Meinel (jameinel)]

I agree that should be fixed, though from what I can read of the code, you shouldn't need to set "local" as it is the default value if it is not otherwise set.
I think Paul's suggestion looks valid, we just need to test it.

[Paul Collins (pjdc)]

> you shouldn't need to set "local" as it is the default value if it is not otherwise set.

FWIW, our scenario is that we have set the model constraint to "volume" but wish to override it selectively where it doesn't make sense for the particular application (e.g. for lower I/O latency or to avoid write/space amplification).

[Evanson Mwangi (mr-parish)]

https://github.com/juju/juju/pull/14655