Manage multi disks snapshots as a single entity

[baby-gnu]

Description

Permit to create, revert, delete, rename and save-as disk snapshot of a virtual machine with several disks in a single operation.

Use case

When a virtual machine has several disks, it rarely make sense to take a disk snapshot of a single disk, data of one disk generally need to be in sync with data of other disks.

For example a virtual machine using multi-disks LVM, taking snapshot of only one disk break the LVM group

Interface Changes
Describe any changed you'd like to see to current interfaces including Sunstone, CLI or/and API

For the CLI, we could have dedicated commands:

• onevm multidisks-snapshot-create
• onevm multidisks-snapshot-delete
• onevm multidisks-snapshot-rename
• onevm multidisks-snapshot-revert

For example, here could be the description for the create:

## USAGE
multidisks-snapshot-create <vmid> <name>

        Takes a new snapshot of all disks or only disks specified with --diskid option.
		This operation needs support from the Datastore drivers: QCOW2 or Ceph.

For Sunstone, we should have a dedicated VM action:

• open a new modal to ask for the name
• display a pre-selected checkbox list of all VM disks by default, user could deselect as needed

Additional Context

Expert users should be able to manage the snapshot of each disk separately like today but a warning and a special option should be required to make sure she knows that it may/will break multidisks snapshots, for example:

onevm disk-snapshot-revert --break-multi-disks-snapshots <VMID> <DISKID> <DISK_SNAPSHOT_ID>

Today, I manage each disk separately on STOPPED VM:

1. stop the VM
2. for each disk, create/revert/delete snapshot with the same name

Progress Status

• Branch created
• Code committed to development branch
• Testing - QA
• Documentation
• Release notes - resolved issues, compatibility, known issues
• Code committed to upstream release/hotfix branches
• Documentation committed to upstream release/hotfix branches