Vdsm Standalone

Vdsm was designed to be driven by oVirt-engine and be its humble server. However, it can be used on its own right. Here there is a crude example on how Vdsm can be used to create and run a virtual machine backed on local storage. In order to use it, you should first have to install vdsm and vdsm-cli, and create a directoy to be used by it for storing VM images and metadata.

  #!/usr/bin/python
  # GPLv2+
  import sys
  import uuid
  import time
  sys.path.append('/usr/share/vdsm')
  import vdscli
  from storage.sd import LOCALFS_DOMAIN, DATA_DOMAIN
  from storage.volume import COW_FORMAT, SPARSE_VOL, LEAF_VOL, BLANK_UUID
  spUUID = str(uuid.uuid4())
  sdUUID = str(uuid.uuid4())
  imgUUID = str(uuid.uuid4())
  volUUID = str(uuid.uuid4())
  # you should manually create the following directory and
  # chown vdsm:kvm /tmp/localstoragedomain
  path = "/tmp/localstoragedomain"
  s = vdscli.connect()
  masterVersion = 1
  hostID = 1
  def vdsOK(d):
      print d
      if d['status']['code']:
     raise Exception(str(d))
      return d
  def waitTask(s, taskid):
      while vdsOK(s.getTaskStatus(taskid))['taskStatus']['taskState'] != 'finished':
          time.sleep(3)
      vdsOK(s.clearTask(taskid))
  vdsOK(s.connectStorageServer(LOCALFS_DOMAIN, "my favorite pet", [dict(id=1, connection=path)]))
  vdsOK(s.createStorageDomain(LOCALFS_DOMAIN, sdUUID, "my local domain", path, DATA_DOMAIN, 0))
  vdsOK(s.createStoragePool(LOCALFS_DOMAIN, spUUID, "pool name", sdUUID, [sdUUID], masterVersion))
  # connect to an existing pool, and become pool manager.
  vdsOK(s.connectStoragePool(spUUID, hostID, "scsikey", sdUUID, masterVersion))
  tid = vdsOK(s.spmStart(spUUID, -1, -1, -1, 0))['uuid']
  waitTask(s, tid)
  sizeGiB = 100
  tid = vdsOK(s.createVolume(sdUUID, spUUID, imgUUID, sizeGiB,
                             COW_FORMAT, SPARSE_VOL, LEAF_VOL,
                             volUUID, "volly",
                             BLANK_UUID, BLANK_UUID))['uuid']
  waitTask(s, tid)
  vmId = str(uuid.uuid4())
  vdsOK(
      s.create(dict(vmId=vmId,
                    drives=[dict(poolID=spUUID, domainID=sdUUID, imageID=imgUUID, volumeID=volUUID)],
                    memSize=256,
           display="vnc",
                    vmName="vm1",
                   )
              )
  )

The below example shows how glusterfs can be used as a DATA_DOMAIN by exploiting the SHAREDFS interface in Vdsm.

• Pre-req:
  1. latest kernel having O_DIRECT support for fuse is needed to be running on the host.
  2. gluster volume must be pre-setup. In the below example assuming hostname as server.example.com, myvol is the name of the gluster volume that must be pre-created and started using gluster commands.

`

#!/usr/bin/python # GPLv2+

import sys import uuid import time

sys.path.append(‘/usr/share/vdsm’)

import vdscli from storage.sd import SHAREDFS_DOMAIN, DATA_DOMAIN, ISO_DOMAIN from storage.volume import COW_FORMAT, SPARSE_VOL, LEAF_VOL, BLANK_UUID

spUUID = str(uuid.uuid4()) sdUUID = str(uuid.uuid4()) imgUUID = str(uuid.uuid4()) volUUID = str(uuid.uuid4())

gluster_conn = “server.example.com:myvol”

s = vdscli.connect()

masterVersion = 1 hostID = 1

def vdsOK(d): print d if d[‘status’][‘code’]: raise Exception(str(d)) return d

def waitTask(s, taskid): while vdsOK(s.getTaskStatus(taskid))[‘taskStatus’][‘taskState’] != ‘finished’: time.sleep(3) vdsOK(s.clearTask(taskid))

vdsOK(s.connectStorageServer(SHAREDFS_DOMAIN, “my gluster mount”, [dict(id=1, spec=gluster_conn, vfs_type=”glusterfs”, mnt_options=””)]))

vdsOK(s.createStorageDomain(SHAREDFS_DOMAIN, sdUUID, “my gluster domain”, gluster_conn, DATA_DOMAIN, 0))

vdsOK(s.createStoragePool(SHAREDFS_DOMAIN, spUUID, “my gluster pool”, sdUUID, [sdUUID], masterVersion))

# connect to an existing pool, and become pool manager. vdsOK(s.connectStoragePool(spUUID, hostID, “scsikey”, sdUUID, masterVersion)) tid = vdsOK(s.spmStart(spUUID, -1, -1, -1, 0))[‘uuid’] waitTask(s, tid)

sizeGiB = 100

tid = vdsOK(s.createVolume(sdUUID, spUUID, imgUUID, sizeGiB, COW_FORMAT, SPARSE_VOL, LEAF_VOL, volUUID, “glustervol”, BLANK_UUID, BLANK_UUID))[‘uuid’] waitTask(s, tid)

vmId = str(uuid.uuid4())

vdsOK( s.create(dict(vmId=vmId, drives=[dict(poolID=spUUID, domainID=sdUUID, imageID=imgUUID, volumeID=volUUID)], memSize=256, display=”vnc”, vmName=”vm-backed-by-gluster”, ) ) )

`