storage: rbd: qemu: Add support for specifying internal RBD snapshots

Some storage systems have internal support for snapshots. Libvirt should
be able to select a correct snapshot when starting a VM.

This patch adds a XML element to select a storage source snapshot for
the RBD protocol which supports this feature.
This commit is contained in:
Peter Krempa 2014-11-11 11:35:25 +01:00
parent 930b77598b
commit 0255660658
10 changed files with 93 additions and 9 deletions

View File

@ -1679,6 +1679,7 @@
<driver name="qemu" type="raw"/>
<source protocol="rbd" name="image_name2">
<host name="hostname" port="7000"/>
<snapshot name="snapname"/>
</source>
<target dev="hdc" bus="ide"/>
<auth username='myuser'>
@ -1952,15 +1953,17 @@
is only valid when the specified storage volume is of 'file' or
'block' type).
<p>
When the disk <code>type</code> is "network", the <code>source</code>
may have zero or more <code>host</code> sub-elements used to
specify the hosts to connect.
The <code>source</code> element may contain the following sub elements:
</p>
<dl>
<dt><code>host</code></dt>
<dd>
<p>
When the disk <code>type</code> is "network", the <code>source</code>
may have zero or more <code>host</code> sub-elements used to
specify the hosts to connect.
The <code>host</code> element supports 4 attributes, viz. "name",
"port", "transport" and "socket", which specify the hostname,
the port number, transport type and path to socket, respectively.
@ -2013,6 +2016,13 @@
AF_UNIX socket.
</p>
</dd>
<dt><code>snapshot</code></dt>
<dd>
The <code>name</code> attribute of <code>snapshot</code> element can
optionally specify an internal snapshot name to be used as the
source for storage protocols.
Supported for 'rbd' <span class="since">since 1.2.11 (QEMU only).</span>
</dd>
</dl>
<p>

View File

@ -1452,6 +1452,14 @@
</choice>
</element>
</zeroOrMore>
<optional>
<element name="snapshot">
<attribute name="name">
<ref name="genericName"/>
</attribute>
<empty/>
</element>
</optional>
<empty/>
</element>
</interleave>

View File

@ -3165,6 +3165,22 @@ virDomainDeviceDefPostParseInternal(virDomainDeviceDefPtr dev,
return -1;
}
/* verify disk source */
if (dev->type == VIR_DOMAIN_DEVICE_DISK) {
virDomainDiskDefPtr disk = dev->data.disk;
/* internal snapshots are currently supported only with rbd: */
if (virStorageSourceGetActualType(disk->src) != VIR_STORAGE_TYPE_NETWORK &&
disk->src->protocol != VIR_STORAGE_NET_PROTOCOL_RBD) {
if (disk->src->snapshot) {
virReportError(VIR_ERR_XML_ERROR, "%s",
_("<snapshot> element is currently supported "
"only with 'rbd' disks"));
return -1;
}
}
}
return 0;
}
@ -5316,10 +5332,14 @@ virDomainDiskSourcePoolDefParse(xmlNodePtr node,
int
virDomainDiskSourceParse(xmlNodePtr node,
xmlXPathContextPtr ctxt,
virStorageSourcePtr src)
{
int ret = -1;
char *protocol = NULL;
xmlNodePtr saveNode = ctxt->node;
ctxt->node = node;
switch ((virStorageType)src->type) {
case VIR_STORAGE_TYPE_FILE:
@ -5372,6 +5392,9 @@ virDomainDiskSourceParse(xmlNodePtr node,
tmp[0] = '\0';
}
/* snapshot currently works only for remote disks */
src->snapshot = virXPathString("string(./snapshot/@name)", ctxt);
if (virDomainStorageHostParse(node, &src->hosts, &src->nhosts) < 0)
goto cleanup;
break;
@ -5397,6 +5420,7 @@ virDomainDiskSourceParse(xmlNodePtr node,
cleanup:
VIR_FREE(protocol);
ctxt->node = saveNode;
return ret;
}
@ -5452,7 +5476,7 @@ virDomainDiskBackingStoreParse(xmlXPathContextPtr ctxt,
goto cleanup;
}
if (virDomainDiskSourceParse(source, backingStore) < 0 ||
if (virDomainDiskSourceParse(source, ctxt, backingStore) < 0 ||
virDomainDiskBackingStoreParse(ctxt, backingStore) < 0)
goto cleanup;
@ -5562,7 +5586,7 @@ virDomainDiskDefParseXML(virDomainXMLOptionPtr xmlopt,
xmlStrEqual(cur->name, BAD_CAST "source")) {
sourceNode = cur;
if (virDomainDiskSourceParse(cur, def->src) < 0)
if (virDomainDiskSourceParse(cur, ctxt, def->src) < 0)
goto error;
source = def->src->path;
@ -5728,7 +5752,8 @@ virDomainDiskDefParseXML(virDomainXMLOptionPtr xmlopt,
_("mirror requires source element"));
goto error;
}
if (virDomainDiskSourceParse(mirrorNode, def->mirror) < 0)
if (virDomainDiskSourceParse(mirrorNode, ctxt,
def->mirror) < 0)
goto error;
}
ready = virXMLPropString(cur, "ready");
@ -16142,11 +16167,12 @@ virDomainDiskSourceFormatInternal(virBufferPtr buf,
VIR_FREE(path);
if (src->nhosts == 0) {
if (src->nhosts == 0 && !src->snapshot) {
virBufferAddLit(buf, "/>\n");
} else {
virBufferAddLit(buf, ">\n");
virBufferAdjustIndent(buf, 2);
for (n = 0; n < src->nhosts; n++) {
virBufferAddLit(buf, "<host");
virBufferEscapeString(buf, " name='%s'",
@ -16163,6 +16189,10 @@ virDomainDiskSourceFormatInternal(virBufferPtr buf,
virBufferAddLit(buf, "/>\n");
}
virBufferEscapeString(buf, "<snapshot name='%s'/>\n",
src->snapshot);
virBufferAdjustIndent(buf, -2);
virBufferAddLit(buf, "</source>\n");
}

View File

@ -2492,6 +2492,7 @@ virDomainDiskRemove(virDomainDefPtr def, size_t i);
virDomainDiskDefPtr
virDomainDiskRemoveByName(virDomainDefPtr def, const char *name);
int virDomainDiskSourceParse(xmlNodePtr node,
xmlXPathContextPtr ctxt,
virStorageSourcePtr src);
bool virDomainHasDiskMirror(virDomainObjPtr vm);

View File

@ -107,6 +107,7 @@ void virDomainSnapshotDefFree(virDomainSnapshotDefPtr def)
static int
virDomainSnapshotDiskDefParseXML(xmlNodePtr node,
xmlXPathContextPtr ctxt,
virDomainSnapshotDiskDefPtr def)
{
int ret = -1;
@ -154,7 +155,7 @@ virDomainSnapshotDiskDefParseXML(xmlNodePtr node,
if (!def->src->path &&
xmlStrEqual(cur->name, BAD_CAST "source")) {
if (virDomainDiskSourceParse(cur, def->src) < 0)
if (virDomainDiskSourceParse(cur, ctxt, def->src) < 0)
goto cleanup;
} else if (!def->src->format &&
@ -352,7 +353,8 @@ virDomainSnapshotDefParse(xmlXPathContextPtr ctxt,
goto cleanup;
def->ndisks = n;
for (i = 0; i < def->ndisks; i++) {
if (virDomainSnapshotDiskDefParseXML(nodes[i], &def->disks[i]) < 0)
if (virDomainSnapshotDiskDefParseXML(nodes[i], ctxt,
&def->disks[i]) < 0)
goto cleanup;
}
VIR_FREE(nodes);

View File

@ -2983,6 +2983,9 @@ qemuBuildNetworkDriveURI(virStorageSourcePtr src,
virBufferStrcat(&buf, "rbd:", src->path, NULL);
if (src->snapshot)
virBufferEscape(&buf, '\\', ":", "@%s", src->snapshot);
if (username) {
virBufferEscape(&buf, '\\', ":", ":id=%s", username);
virBufferEscape(&buf, '\\', ":",

View File

@ -1848,6 +1848,7 @@ virStorageSourceCopy(const virStorageSource *src,
VIR_STRDUP(ret->driverName, src->driverName) < 0 ||
VIR_STRDUP(ret->relPath, src->relPath) < 0 ||
VIR_STRDUP(ret->backingStoreRaw, src->backingStoreRaw) < 0 ||
VIR_STRDUP(ret->snapshot, src->snapshot) < 0 ||
VIR_STRDUP(ret->compat, src->compat) < 0)
goto error;
@ -2280,6 +2281,13 @@ virStorageSourceParseRBDColonString(const char *rbdstr,
*p = '\0';
}
/* snapshot name */
if ((p = strchr(src->path, '@'))) {
if (VIR_STRDUP(src->snapshot, p + 1) < 0)
goto error;
*p = '\0';
}
/* options */
if (!options)
return 0; /* all done */

View File

@ -238,6 +238,7 @@ struct _virStorageSource {
char *path;
int protocol; /* virStorageNetProtocol */
char *volume; /* volume name for remote storage */
char *snapshot; /* for storage systems supporting internal snapshots */
size_t nhosts;
virStorageNetHostDefPtr hosts;
virStorageSourcePoolDefPtr srcpool;

View File

@ -5,4 +5,8 @@ unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -usb \
-drive 'file=rbd:pool/image:auth_supported=none:\
mon_host=mon1.example.org\:6321\;mon2.example.org\:6322\;\
mon3.example.org\:6322,if=virtio,format=raw' \
-drive file=rbd:pool/image@asdf:auth_supported=none,if=virtio,format=raw \
-drive 'file=rbd:pool/image@foo:auth_supported=none:\
mon_host=mon1.example.org\:6321\;mon2.example.org\:6322\;\
mon3.example.org\:6322,if=virtio,format=raw' \
-net none -serial none -parallel none

View File

@ -29,6 +29,23 @@
</source>
<target dev='vda' bus='virtio'/>
</disk>
<disk type='network' device='disk'>
<driver name='qemu' type='raw'/>
<source protocol='rbd' name='pool/image'>
<snapshot name='asdf'/>
</source>
<target dev='vdb' bus='virtio'/>
</disk>
<disk type='network' device='disk'>
<driver name='qemu' type='raw'/>
<source protocol='rbd' name='pool/image'>
<host name='mon1.example.org' port='6321'/>
<host name='mon2.example.org' port='6322'/>
<host name='mon3.example.org' port='6322'/>
<snapshot name='foo'/>
</source>
<target dev='vdc' bus='virtio'/>
</disk>
<controller type='usb' index='0'/>
<controller type='ide' index='0'/>
<controller type='pci' index='0' model='pci-root'/>