LVM support in cinder charm: migration to cinder-lvm¶
This page has been identified as being affected by the breaking changes introduced between versions 2.9.x and 3.x of the Juju client. Read support note Breaking changes between Juju 2.9.x and 3.x before continuing.
As of the 21.10 release of OpenStack Charms, support for local (LVM) Cinder storage in the cinder charm is deprecated. This functionality has been de-coupled and is now managed by the cinder-lvm subordinate charm. This page shows how to migrate from the cinder charm to the cinder-lvm charm.
The migration will necessitate a short cloud maintenance window, enough time to deploy the subordinate charm onto the existing machine(s). Cloud operators will be unable to create new Cinder volumes during this window.
The LVM feature in the cinder charm is potentially in use if the
block-device option is set to a value other than ‘None’. Check this with
the following command:
juju config cinder block-device
Begin by disabling the LVM feature in the cinder charm:
juju config cinder block-device=None
Migrating LVM functionality amounts to setting the cinder-lvm charm configuration options to the same values as those used for the identically named options in the cinder charm:
volume-backend-name option specific to the cinder-lvm charm
needs to be set to ‘cinder_lvm’, the LVM backend driver.
All of this configuration can be stated most easily with a configuration file,
cinder-lvm: block-device: sdb ephemeral-unmount: <null> remove-missing: false remove-missing-force: false overwrite: false volume-group: cinder-volumes volume-backend-name: cinder_lvm
Now deploy cinder-lvm while referencing the configuration file and then add a relation to the cinder application:
juju deploy --config cinder-lvm.yaml cinder-lvm juju integrate cinder-lvm:storage-backend cinder:storage-backend
Verify that Cinder volumes can be created as usual and that existing VMs utilising Cinder volumes have not been adversely affected.