On Wed, Apr 17, 2019 at 09:09:03 -0500, Eric Blake wrote:
Introduce a bunch of new public APIs related to backup checkpoints. Checkpoints are modeled heavily after virDomainSnapshotPtr (both represent a point in time of the guest), although a snapshot exists with the intent of rolling back to that state, while a checkpoint exists to make it possible to create an incremental backup at a later time.
The following map shows the API relations to snapshots, with new APIs on the right:
Operate on a domain object to create/redefine a child: virDomainSnapshotCreateXML virDomainCheckpointCreateXML
Operate on a child object for lifetime management: virDomainSnapshotDelete virDomainCheckpointDelete virDomainSnapshotFree virDomainCheckpointFree virDomainSnapshotRef virDomainCheckpointRef
Operate on a child object to learn more about it: virDomainSnapshotGetXMLDesc virDomainCheckpointGetXMLDesc virDomainSnapshotGetConnect virDomainCheckpointGetConnect virDomainSnapshotGetDomain virDomainCheckpointGetDomain virDomainSnapshotGetName virDomainCheckpiontGetName virDomainSnapshotGetParent virDomainCheckpiontGetParent virDomainSnapshotHasMetadata virDomainCheckpointHasMetadata virDomainSnapshotIsCurrent virDomainCheckpointIsCurrent
The 'current' checkpoint has very sparse documentation. While it makes some sense for the current snapshot to exist I'm not persuaded we need this for checkpoints. In case of checkpoints the bitmaps backing it track the state even if you create a new bitmap unlike checkpoints. Thus it does not seem to make sense to me. If you think it does please elaborate, ideally in form of documentation.
Operate on a domain object to list all children: virDomainSnapshotNum (no counterpart, this is the old virDomainSnapshotListNames racy interface) virDomainSnapshotListAllSnapshots virDomainListAllCheckpoints
Operate on a child object to list descendents: virDomainSnapshotNumChildren (no counterpart, this is the old virDomainSnapshotListChildrenNames racy interface) virDomainSnapshotListAllChildren virDomainCheckpointListAllChildren
Operate on a domain to locate a particular child: virDomainSnapshotLookupByName virDomainCheckpointLookupByName virDomainHasCurrentSnapshot virDomainHasCurrentCheckpoint virDomainSnapshotCurrent virDomainCheckpointCurrent
Operate on a snapshot to roll back to earlier state: virDomainSnapshotRevert (no counterpart, instead checkpoints are used in incremental backups via
This patch or a different one should also add docs to virDomainSnapshotRevert that outline what happens to the checkpoints when reverting snapshots. Basically what should happen is that an alternate reality should probably be created as the disk images can change at that point
XML to virDomainBackupBegin)
Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>