Migration of resources such as virtual machines and volumes is essential functionality for cloud operators, enabling them to load balance or perform maintenance operations on underlying compute, storage or network resources without major downtime. CloudStack provides impressive functionality to migrate VMs and volumes, with different APIs for different use-cases:
Most of these actions are also available in the CloudStack UI, which makes life easier when there are not many migrations to be carried out at once. Keeping with this notion of making life easier, the next CloudStack LTS version will come with improvements to VM and volume migration in CloudStack UI, with updated UI forms to migrate instance to another host, migrate instance to another primary storage and migrate volume.
The UI form Migrate instance to another host will now allow migration of a VM and its volumes, with the option to select specific/different primary storages for each volume. To aid this selection, information about primary storage such as scope, usage, etc. is also shown. By default, the ‘automatically assign’ option is selected for the primary storage of each volume, assigned based on availability in the VM’s cluster and the volume’s existing storage. Different primary storage will be assigned to the volume only when the existing primary storage of the volume is inaccessible in the VM’s destination cluster. Otherwise, if primary storage is chosen from the list of storage options, CloudStack will try to migrate the volume to the chosen storage.
Similar to the above form, the UI form Migrate instance to another primary storage will now allow the migration of different volumes of the VM to a different primary storage. Like the above form, this form also allows Automatically assign options for the VM volumes.
Thе UI form Migrate volume will also provide details of available primary storage instead of simple list of storage names:
These updated forms will not only improve the user experience for different migration cases in CloudStack, but will also add support for simultaneous compute and storage migrations of user VMs. These changes will be available in the next LTS version of CloudStack which is scheduled to be released in Q3/Q4 2022.