oVirt备份-还原磁盘快照

谁践踏了优雅 2023-10-08 09:28 15阅读 0赞

备份\-还原磁盘快照

摘要

此功能是补充组件，用于提供备份和还原虚拟机的功能。该功能引入了对使用REST-API下载和上传磁盘快照的支持。使用[ovirt-imageio][]促进图像传输

使用oVirt Python-SDK可简化以下备份/还原示例。oVirt REST-API / SDK可以类似的方式使用。

后备

下载VM OVF

[完整的例子][Link 1]

为了获取VM配置数据，应指定'all\_content'标志。然后，可以将其写入一个新文件\-OVF。注意：OVF包含有关磁盘和快照的足够信息，可以将VM恢复到原始状态（例如，别名/描述/日期）。但是，它不是由系统自动解析的，而是应该由SDK用户完成的。

vm\_name = 'myvm'

vm = vms\_service.list(search="name=%s" % vm\_name, all\_content=**True**)\[0\]

ovf\_filename = "%s.ovf" % vm.id

with open(ovf\_filename, "wb") as ovf\_file:

ovf\_file.write(vm.initialization.configuration.data)

下载磁盘

[完整的例子][Link 2]

以下示例演示了下载指定磁盘的非活动磁盘快照的过程。因此，为了也包括活动层，请预先为磁盘创建一个新的快照，或者使用“ [下载磁盘”示例][Link 3]下载活动磁盘快照

为了下载活跃

*  对于每个磁盘，遍历其磁盘快照并执行映像传输。

*  *\# Set relevant disk and stroage domain IDs*
 *  disk\_id = 'ccdd6487-0a8f-40c8-9f45-40e0e2b30d79'
 *  sd\_name = 'mydata'
 *  
 *  *\# Get a reference to the storage domains service:*
 *  storage\_domains\_service = system\_service.storage\_domains\_service()
 *  
 *  *\# Look up for the storage domain by name:*
 *  storage\_domain = storage\_domains\_service.list(search='name=%s' % sd\_name)\[0\]
 *  
 *  *\# Get a reference to the storage domain service in which the disk snapshots reside:*
 *  storage\_domain\_service = storage\_domains\_service.storage\_domain\_service(storage\_domain.id)
 *  
 *  *\# Get a reference to the disk snapshots service:*
 *  disk\_snapshot\_service = storage\_domain\_service.disk\_snapshots\_service()
 *  
 *  *\# Get a list of disk snapshots by a disk ID*
 *  all\_disk\_snapshots = disk\_snapshot\_service.list()
 *  
 *  *\# Filter disk snapshots list by disk id*
 *  disk\_snapshots = \[s for s in all\_disk\_snapshots if s.disk.id == disk\_id\]
 *  
 *  *\# Download disk snapshots*
 *  for disk\_snapshot in disk\_snapshots:
 *  download\_disk\_snapshot(disk\_snapshot)

*  应使用“快照”属性指定ImageTransfer对象。

*  transfer = transfers\_service.add(
 *  types.ImageTransfer(
 *  snapshot=types.DiskSnapshot(id=disk\_snapshot\_id),
 *  direction=types.ImageTransferDirection.DOWNLOAD,
 *  )
 *  )

恢复

[完整的例子][Link 4]

组成磁盘快照链

使用保存的图像文件，创建一个磁盘快照链。通过获取每个文件的卷信息（使用qemu-img）并找到后备文件名（卷的父文件）来构建链。通过维护父卷和子卷之间的映射，我们可以从基本卷开始构建链。

volumes\_info = \{\} *\# \{filename -> vol\_info\}*

backing\_files = \{\} *\# \{backing\_file (parent) -> vol\_info (child)\}*

for root, dirs, file\_names in os.walk(disk\_path):

for file\_name in file\_names:

volume\_info = get\_volume\_info("%s/%s" % (disk\_path, file\_name))

volumes\_info\[file\_name\] = volume\_info

if 'full-backing-filename' in volume\_info:

backing\_files\[volume\_info\['full-backing-filename'\]\] = volume\_info

base\_volume = \[v for v in volumes\_info.values() if 'full-backing-filename' not in v \]\[0\]

child = backing\_files\[base\_volume\['filename'\]\]

images\_chain = \[base\_volume\]

while child != **None**:

images\_chain.append(child)

parent = child

if parent\['filename'\] in backing\_files:

child = backing\_files\[parent\['filename'\]\]

else:

child = **None**

return images\_chain

创建磁盘

对于每个磁盘，使用上一步中生成的映像链调用基本映像的磁盘创建。磁盘的内容将在以后的步骤中上载。

base\_image = images\_chain\[0\]

initial\_size = base\_image\['actual-size'\]

provisioned\_size = base\_image\['virtual-size'\]

image\_id = os.path.basename(base\_image\['filename'\])

disk = disks\_service.add(

types.Disk(

id=disk\_id,

image\_id=image\_id,

name=disk\_id,

format=types.DiskFormat.RAW,

provisioned\_size=provisioned\_size,

initial\_size=initial\_size,

storage\_domains=\[

types.StorageDomain(

name=sd\_name

)

从OVF添加VM

通过在配置元素中指定ovf数据来添加保存的VM。

ovf\_file\_path = 'c3a8e806-106d-4aff-b59a-3a113eabf5a9.ovf'

ovf\_data = open(ovf\_file\_path, 'r').read()

vms\_service = system\_service.vms\_service()

vm = vms\_service.add(

types.Vm(

cluster=types.Cluster(

name='Default',

initialization = types.Initialization(

configuration = types.Configuration(

type = types.ConfigurationType.OVF,

data = ovf\_data

)

创建快照

对于链中的每个磁盘快照，使用磁盘ID和映像ID（以及可选的已保存描述）创建快照。

*\# Locate the service that manages the snapshots of the virtual machine:*

snapshots\_service = vm\_service.snapshots\_service()

*\# Add the new snapshot:*

snapshot = snapshots\_service.add(

types.Snapshot(

description=description,

disk\_attachments=\[

types.DiskAttachment(

disk=types.Disk(

id=disk\_id,

image\_id=image\_id

)

上传磁盘

对于链中的每个磁盘快照，开始上载传输。

*\# Get a reference to the service that manages the image transfer:*

transfers\_service = system\_service.image\_transfers\_service()

*\# Add a new image transfer:*

transfer = transfers\_service.add(

types.ImageTransfer(

snapshot=types.DiskSnapshot(id=disk\_snapshot\_id),

direction=types.ImageTransferDirection.UPLOAD,

)

*\# Get reference to the created transfer service:*

transfer\_service = transfers\_service.image\_transfer\_service(transfer.id)

while transfer.phase == types.ImageTransferPhase.INITIALIZING:

time.sleep(1)

transfer = transfer\_service.get()

try:

proxy\_url = urlparse(transfer.proxy\_url)

proxy\_connection = get\_proxy\_connection(proxy\_url)

path = disk\_path

*\# Set needed headers for uploading:*

upload\_headers = \{

'Authorization': transfer.signed\_ticket,

with open(path, "rb") as disk:

size = os.path.getsize(path)

chunk\_size = 1024 \* 1024 \* 8

pos = 0

while pos < size:

*\# Extend the transfer session.*

transfer\_service.extend()

*\# Set the content range, according to the chunk being sent.*

upload\_headers\['Content-Range'\] = "bytes %d-%d/%d" % (pos, min(pos \+ chunk\_size, size) \- 1, size)

*\# Perform the request.*

proxy\_connection.request(

'PUT',

proxy\_url.path,

disk.read(chunk\_size),

headers=upload\_headers,

)

*\# Print response*

r = proxy\_connection.getresponse()

print r.status, r.reason, "Completed", "\{:.0%\}".format(pos / float(size))

*\# Continue to next chunk.*

pos \+= chunk\_size

print "Completed", "\{:.0%\}".format(pos / float(size))

finally:

*\# Finalize the session.*

transfer\_service.finalize()

附录

Python SDK范例

*  [下载VM OVF][Link 1]
 *  [下载磁盘快照][Link 2]
 *  [上传磁盘快照][Link 4]
 *  [下载磁盘][Link 3]
 *  [上传磁盘][Link 5]

[ovirt-imageio]: https://github.com/oVirt/ovirt-imageio
[Link 1]: https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/examples/download_vm_ovf.py
[Link 2]: https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/examples/download_disk_snapshots.py
[Link 3]: https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/examples/download_disk.py
[Link 4]: https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/examples/upload_disk_snapshots.py
[Link 5]: https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/examples/upload_disk.py