charm-guide/doc/source/project/procedures/cinder-lvm-tgt-to-lio-migration.rst

Target helper migration: TGT to LIO (cinder-lvm)

Starting with the Wallaby release, the 'lioadm' library (python3-rtslib-fb) is the default target helper installed with the cinder-common package. New charm deployments will use the new helper by default without manual user intervention. Deployments upgrading from Victoria will automatically continue to use the legacy version, 'tgtadm', but it is recommended that users migrate to the new helper.

The steps to transition to the new helper are the following:

1 - Upgrade cinder and cinder-lvm charms to the latest version from the Victoria channel.

2 - Once everything is up and running, upgrade cinder and cinder-lvm charms to the latest version from the system in Wallaby channel.

3 - Execute the OpenStack upgrade transitioning from Victoria to Wallaby:

juju config cinder openstack-origin=cloud:focal-wallaby

4 - Create a new cinder-lvm application, as in the example below, with the same configuration as the previous cinder-lvm, but adding the new target_helper config, and an alternative target_port.

Important

The new application must have a different name than the previous one, as you need a way to differentiate new and old backends. The alias option can also be used to differentiate the backends, but it is not mandatory. A different target_port is also recommended, to avoid conflicts with the previous backend.

applications:
  cinder-lvm-lio:
    charm: cinder-lvm
    channel: wallaby/stable
    options:
      alias: stsstack-lio
      block-device: /var/lib/lvm_pool0.img|20G
      volume-group: cinder-volumes-stsstack
      config-flags: target_helper=lioadm,target_port=3261
relations:
  - [ cinder, cinder-lvm-lio ]

Install the new application:

juju export-bundle > current-juju.yaml
juju deploy ./current-juju.yaml --overlay ./cinder-lvm-lio.yaml

5 - Disable old tgtadm backends and services:

cinder service-disable juju-348a1c-focal-ussuri-lvm-3-0@LVM-stsstack \
cinder-volume

6 - Optionally, migrate volumes to the new backend and remove the old backend/application.

openstack volume migrate --host \
juju-8f5d46-focal-ussuri-lvm-graylog-0@LVM-stsstack-lio v1