[libvirt] [PATCH 0/7] Keep non-persistent changes alive in snapshot

Kothapally Madhu Pavan kmp at linux.vnet.ibm.com
Mon Oct 30 08:51:49 UTC 2017

Restoring to a snapshot should not overwrite the persistent XML configuration
of a snapshot as a side effect. This patchset fixes the same. Currently,
virDomainSnapshotDef only saves active domain definition of the guest.
And on restore the active domain definition is used as both active and
inactive domain definitions. This will make the non-persistent changes
persistent in snapshot image. This patchset allows to save inactive domain
definition as well and on snapshot-revert non-persistent configuration is
restored as is.

Currently, snapshot-revert is making non-presistent changes as persistent.
Here are the steps to reproduce.
Step1: virsh define $dom
Step2: virsh attach-device $dom $memory-device.xml --live
Step3: virsh snapshot-create $dom
Step4: virsh destroy $dom
Step5: virsh snapshot-revert $dom $snapshot-name
Step6: virsh destroy $dom
Step7: virsh start $dom
Here we still have $memory-device attached in Step2.

This patchset is attempting to solve this issue. This patchset will also
allow user to dump and edit inactive XML configuration of a snapshot.
Dumping inactive domain definition of a snapshot is important as
--redefine uses snapshot-dumpxml output to redefine a snapshot.

Kothapally Madhu Pavan (7):
  qemu: Store inactive domain configuration in snapshot
  qemu: Use active and inactive snapshot configuration on restore
  conf: Allow editing inactive snapshot configuration
  virsh: Dump inactive XML configuration of snapshot using
  virsh: Edit inactive XML configuration of snapshot using snapshot-edit
  virsh: Allow restoring snapshot with non-persistent configuration
  tests: docs: Add schema and testcase for domainsnapshot

 docs/schemas/domainsnapshot.rng                    | 19 +++++
 include/libvirt/libvirt-domain-snapshot.h          | 10 ++-
 include/libvirt/libvirt-domain.h                   |  1 +
 src/conf/domain_conf.c                             |  6 +-
 src/conf/domain_conf.h                             |  2 +
 src/conf/snapshot_conf.c                           | 48 ++++++++++++-
 src/conf/snapshot_conf.h                           |  1 +
 src/qemu/qemu_driver.c                             | 33 ++++++++-
 .../full_domain_withinactive.xml                   | 83 ++++++++++++++++++++++
 tests/domainsnapshotxml2xmltest.c                  |  1 +
 tools/virsh-snapshot.c                             | 20 ++++++
 tools/virsh.pod                                    | 37 +++++++++-
 12 files changed, 251 insertions(+), 10 deletions(-)
 create mode 100644 tests/domainsnapshotxml2xmlout/full_domain_withinactive.xml


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