Commit Graph

4 Commits

Author SHA1 Message Date
Eric Blake
252958ee16 backup: Document new XML for backups
Prepare for new backup APIs by describing the XML that will represent
a backup.  The XML resembles snapshots and checkpoints in being able
to select actions for a set of disks, but has other differences.  It
can support both push model (the hypervisor does the backup directly
into the destination file) and pull model (the hypervisor exposes an
access port for a third party to grab what is necessary).  Add
testsuite coverage for some minimal uses of the XML.

The <disk> element within <domainbackup> tries to model the same
elements as a <disk> under <domain>, but sharing the RNG grammar
proved to be hairy. That is in part because while <domain> use
<source> to describe a host resource in use by the guest, a backup job
is using a host resource that is not visible to the guest: a push
backup action is instead describing a <target> (which ultimately could
be a remote network resource, but for simplicity the RNG just
validates a local file for now), and a pull backup action is instead
describing a temporary local file <scratch> (which probably should not
be a remote resource).  A future refactoring may thus introduce some
way to parameterize RNG to accept <disk type='FOO'>...</disk> so that
the name of the subelement can be <source> for domain, or <target> or
<scratch> as needed for backups. Future patches may improve this area
of code.

Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-12-10 12:41:56 +01:00
Eric Blake
7efe930ec3 backup: Prevent snapshots and checkpoints at same time
Earlier patches mentioned that the initial implementation will prevent
snapshots and checkpoints from being used on the same domain at once.
However, the actual restriction is done in this separate patch to make
it easier to lift that restriction via a revert, when we are finally
ready to tackle that integration in the future.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-07-29 08:22:29 -05:00
Eric Blake
9943c42a22 backup: Document nuances between different state capture APIs
Now that various new API have been added or are coming soon, it is
worth a landing page that gives an overview of capturing various
pieces of guest state, and which APIs are best suited to which tasks.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-07-26 16:48:58 -05:00
Eric Blake
d85842cfd7 backup: Document new XML for checkpoints
Prepare for new checkpoint APIs by describing the XML that will
represent a checkpoint.  The checkpoint XML is modeled heavily after
virDomainSnapshotPtr. See the docs for more details.

Add testsuite coverage for some minimal uses of the XML (bare minimum,
the sample from html, and a full dumpxml, and some counter-examples
that should fail schema validation). Although use of the REDEFINE flag
will require the <domain> subelement to be present, it is easier for
most of the tests to provide counterpart output produced with the
NO_DOMAIN flag (particularly since synthesizing a valid <domain>
during testing is not trivial).

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-07-26 16:48:58 -05:00