On Wed, Jun 13, 2018 at 11:42:27AM -0500, Eric Blake wrote:
> Introduce a few more new public APIs related to incremental backups.
> This builds on the previous notion of a checkpoint (without an
> existing checkpoint, the new API is a full backup, differing only
> from virDomainCopy in the point of time chosen); and also allows
> creation of a new checkpoint at the same time as starting the backup
> (after all, an incremental backup is only useful if it covers the
> state since the previous backup). It also enhances event reporting
> for signaling when a push model backup completes (where the
> hypervisor creates the backup); note that the pull model does not
> have an event (starting the backup lets a third party access the
> data, and only the third party knows when it is finished).
First, thanks for the work! (And for doing the detailed write-ups, as
is your wont.)
A super minor note: I hope you'll also add the API names in the commit
message itself (like you did in the past, for the older APIs); it will
be handy when browsing `git log` later.
So far I see the new APIs are:
- virDomainBackupBegin()
- virDomainBackupGetXMLDesc()
- virDomainBackupEnd()
So, OpenStack Nova currently still uses virDomainBlockRebase(); it
hasn't even moved to the newer virDomainBlockCopy(). But as we know,
currently both of them have the limitation of having to undefine and
then re-define the guest XML.
As you suggested elsewhere, probably I could explore (once they are
'frozen') moving to these proposed APIs, which will work without having
to do the undefine + re-define dance.
> Signed-off-by: Eric Blake <eblake@xxxxxxxxxx>
> ---
> include/libvirt/libvirt-domain-checkpoint.h | 11 ++
> include/libvirt/libvirt-domain.h | 14 +-
> src/driver-hypervisor.h | 14 ++
> src/libvirt-domain-checkpoint.c | 200 ++++++++++++++++++++++++++++
> src/libvirt-domain.c | 8 +-
> src/libvirt_public.syms | 3 +
> tools/virsh-domain.c | 3 +-
> 7 files changed, 249 insertions(+), 4 deletions(-)
>
> diff --git a/include/libvirt/libvirt-domain-checkpoint.h b/include/libvirt/libvirt-domain-checkpoint.h
> index 4a7dc73089..c1d382fddc 100644
> --- a/include/libvirt/libvirt-domain-checkpoint.h
> +++ b/include/libvirt/libvirt-domain-checkpoint.h
> @@ -144,4 +144,15 @@ int virDomainCheckpointDelete(virDomainCheckpointPtr checkpoint,
> int virDomainCheckpointRef(virDomainCheckpointPtr checkpoint);
> int virDomainCheckpointFree(virDomainCheckpointPtr checkpoint);
>
> +/* Begin an incremental backup job, possibly creating a checkpoint. */
> +int virDomainBackupBegin(virDomainPtr domain, const char *diskXml,
> + const char *checkpointXml, unsigned int flags);
> +
> +/* Learn about an ongoing backup job. */
> +char *virDomainBackupGetXMLDesc(virDomainPtr domain, int id,
> + unsigned int flags);
> +
> +/* Complete an incremental backup job. */
> +int virDomainBackupEnd(virDomainPtr domain, int id, unsigned int flags);
[...]
--
/kashyap
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