Based on discussion, I've modified the snapshot API to the below. I've
incorporated most of the semantic changes we talked about; the renaming
of various API calls I've left for later, since it is a minor point.
More comments welcome!
/* NOTE: struct _virDomainSnapshot is a private structure, ala
* struct _virDomain.
*/
typedef struct _virDomainSnapshot virDomainSnapshot;
/* Take a snapshot of the current VM state. Throws an error if
* the VM is not currently running */
virDomainSnapshotPtr virDomainSnapshotCreateXML(virDomainPtr domain,
const char *xmlDesc,
unsigned int flags);
/* Dump the XML of a snapshot */
/* NOTE: see below for proposed XML */
char *virDomainSnapshotGetXMLDesc(virDomainSnapshotPtr snapshot,
unsigned int flags);
/* Return the number of snapshots for this domain */
int virDomainSnapshotNum(virDomainPtr domain, unsigned int flags);
/* Get the names of all snapshots for this domain */
int virDomainListSnapshotNames(virDomainPtr domain, char **names, int nameslen,
unsigned int flags);
/* Get a handle to a named snapshot */
virDomainSnapshotPtr virDomainSnapshotLookupByName(virDomainPtr domain,
const char *name,
unsigned int flags);
/* Start the guest "domain" from the snapshot "snapshot" */
int virDomainCreateWithSnapshot(virDomainPtr domain,
virDomainSnapshotPtr snapshot,
unsigned int flags);
/* Deactivate a snapshot - with no flags, the snapshot is not used anymore,
* but also not removed. With a MERGE flag, it merges the snapshot into
* the parent snapshot (or the base image, if there is no parent snapshot).
* Note that if other snapshots would be discarded because of this
* MERGE action, this operation will fail. If that is really what is intended,
* use MERGE_FORCE.
*
* With a DISCARD flag, it deletes the snapshot. Note that if other snapshots
* would be discarded because of this delete action, this operation will
* fail. If this is really what is intended, use DISCARD_FORCE.
*
* MERGE, MERGE_FORCE, DISCARD, and DISCARD_FORCE are mutually-exclusive.
*
* Note that this operation can generally only happen when the domain is shut
* down, though this is hypervisor-specific */
typedef enum {
VIR_DOMAIN_SNAPSHOT_DEACTIVATE_MERGE,
VIR_DOMAIN_SNAPSHOT_DEACTIVATE_MERGE_FORCE,
VIR_DOMAIN_SNAPSHOT_DEACTIVATE_DISCARD,
VIR_DOMAIN_SNAPSHOT_DEACTIVATE_DISCARD_FORCE,
} virDomainSnapshotDeactivate;
int virDomainSnapshotDeactivate(virDomainSnapshotPtr snapshot,
unsigned int flags);
int virDomainSnapshotFree(virDomainSnapshotPtr snapshot);
NOTE: During snapshot creation, *none* of the fields are required. That is,
you can call virDomainSnapshotCreateXML() with an XML of "<domainsnapshot/>".
In this case, the individual driver will make up a <name> for you, the
<creationdate> will be set to the current time+date, <description> will be
empty, <state> will be "off", <compression> will be empty, and <parent> will
be set to the current snapshot (if any). If you do want to specify some
fields during virDomainSnapshotCreateXML(), note that the only ones that are
settable are <name>, <description>, and <compression>; the rest are ignored,
and filled in by the driver when the snapshot is actually created.
NOTE: <compression> is used to compress snapshots, and may or may not be
supported by individual hypervisor implementations. If <compression> is
specified and the underlying hypervisor does not support it, an error will
be thrown.
<domainsnapshot>
<name>XYZ</name>
<creationdate>...</creationdate>
<description>...</description>
<state>RUNNING</state>
<domain>
<uuid>XXXXX-XXXX-XXXX-XXXX-XXXXXXXXX</uuid>
</domain>
<compression>gzip</compression>
<parent>
<name>ABC</name>
</parent>
</domainsnapshot>
The virsh commands will be:
virsh snapshot-create [--compress] <dom> <xmlfile>
virsh snapshot-list <dom>
virsh snapshot-dumpxml <dom> <name>
virsh create-with-snapshot <dom> <snapshotname>
virsh snapshot-deactivate <dom> <snapshotname> [--merge|--delete|--mergeforce|--mergedelete]
--
Chris Lalancette
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