KVM虚拟化笔记（九）------kvm虚拟机快照备份-阿里云开发者社区

kvm虚拟机默认使用raw格式的镜像格式，性能最好，速度最快，它的缺点就是不支持一些新的功能，如支持镜像,zlib磁盘压缩,AES加密等。要使用镜像功能，磁盘格式必须为qcow2。下面开始kvm虚拟机快照备份的过程

1，查看现有磁盘镜像格式与转换

（1）查看现有磁盘的格式

[root@KVM test]# qemu-img info hadoop3.img 
image: hadoop3.img

file format: raw
virtual size: 10G (10737418240 bytes)
disk size: 877M

把raw格式转换成qcow2格式

（2）关闭需要转换磁盘的虚拟机

[root@KVM test]# virsh destroy hadoop3
Domain hadoop3 destroyed

[root@KVM test]# virsh list --all     

 Id    Name                           State
----------------------------------------------------

 1     win7                           running

 6     hadoop2                        running

 -     hadoop1                        shut off

 -     hadoop3                        shut off

 -     hadoop4                        shut off

（3）转换磁盘的格式

[root@KVM test]# qemu-img convert -f raw -O qcow2 hadoop3.img hadoop3.qcow2

-f 源镜像的格式

-o 目标镜像的格式

查看转换后的格式，已经转换成了qcow2, 这里是拷贝一份，并将格式转成qcow2

[root@KVM test]# qemu-img convert -f raw -O qcow2 hadoop3.img hadoop3.qcow2

[root@KVM test]# ll
total 14975352
-rwxr-xr-x 1 root root 10737418240 Feb  4 14:38 hadoop1.img
-rwxr-xr-x 1 qemu qemu 10737418240 Feb  4 16:51 hadoop2.img
-rwxr-xr-x 1 root root 10737418240 Feb  4 16:48 hadoop3.img
-rw-r--r-- 1 root root   923926528 Feb  4 16:51 hadoop3.qcow2
-rwxr-xr-x 1 root root 10737418240 Feb  4 15:11 hadoop4.img
-rwxr-xr-x 1 qemu qemu  8589934592 Feb  2 15:03 win7.img

[root@KVM test]# qemu-img info hadoop3.qcow2 
image: hadoop3.qcow2

file format: qcow2
virtual size: 10G (10737418240 bytes)
disk size: 881M
cluster_size: 65536

2，修改虚拟机配置文件

[root@KVM qemu]# virsh edit hadoop3

<name>hadoop3</name>

<os>

</os>

<acpi/>

<apic/>

<pae/>

</features>

<on_poweroff>destroy</on_poweroff>

<on_reboot>restart</on_reboot>

<on_crash>restart</on_crash>

<emulator>/usr/libexec/qemu-kvm</emulator>

3，对虚拟机进行快照管理

(1)对hadoop3虚拟机创建快照

[root@KVM qemu]# virsh snapshot-create hadoop3
Domain snapshot 1454577228 created

（2）查看虚拟机快照的版本

[root@KVM qemu]# virsh snapshot-list hadoop3  

 Name                 Creation Time             State
------------------------------------------------------------

 1454577228           2016-02-04 17:13:48 +0800 shutoff

（3）查看当前虚拟机镜像快照的版本

[root@KVM qemu]# virsh snapshot-current hadoop3
<domainsnapshot>

  <name>1454577442</name>

  <state>shutoff</state>

  <parent>

    <name>1454577228</name>

  </parent>

  <creationTime>1454577442</creationTime>

  <memory snapshot='no'/>

  <disks>

    <disk name='hda' snapshot='internal'/>

    <disk name='hdc' snapshot='no'/>

  </disks>

  <domain type='qemu'>

    <name>hadoop3</name>

    <uuid>586b3cae-943f-e283-d8e7-ed72b01bfa34</uuid>

    <memory unit='KiB'>1048576</memory>

    <currentMemory unit='KiB'>1048576</currentMemory>

    <vcpu placement='static'>1</vcpu>

    <os>

      <type arch='x86_64' machine='rhel6.6.0'>hvm</type>

      <boot dev='hd'/>

    </os>

    <features>

      <acpi/>

      <apic/>

      <pae/>

    </features>

    <clock offset='localtime'/>

    <on_poweroff>destroy</on_poweroff>

    <on_reboot>restart</on_reboot>

    <on_crash>restart</on_crash>

    <devices>

      <emulator>/usr/libexec/qemu-kvm</emulator>

      <disk type='file' device='disk'>

        <driver name='qemu' type='qcow2' cache='none'/>

        <source file='/images/test/hadoop3.qcow2'/>

        <target dev='hda' bus='ide'/>

        <address type='drive' controller='0' bus='0' target='0' unit='0'/>

      </disk>

      <disk type='block' device='cdrom'>

        <driver name='qemu' type='raw'/>

        <target dev='hdc' bus='ide'/>

        <readonly/>

        <address type='drive' controller='0' bus='1' target='0' unit='0'/>

      </disk>

      <controller type='usb' index='0' model='ich9-ehci1'>

        <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x7'/>

      </controller>

      <controller type='usb' index='0' model='ich9-uhci1'>

        <master startport='0'/>

        <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0' multifunction='on'/>

      </controller>

      <controller type='usb' index='0' model='ich9-uhci2'>

        <master startport='2'/>

        <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x1'/>

      </controller>

      <controller type='usb' index='0' model='ich9-uhci3'>

        <master startport='4'/>

        <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x2'/>

      </controller>

      <controller type='ide' index='0'>

        <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>

      </controller>

      <interface type='network'>

        <mac address='52:54:00:fe:f5:a3'/>

        <source network='default'/>

        <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>

      </interface>

      <serial type='pty'>

        <target port='0'/>

      </serial>

      <console type='pty'>

        <target type='serial' port='0'/>

      </console>

      <input type='mouse' bus='ps2'/>

      <graphics type='vnc' port='5913' autoport='no' listen='0.0.0.0'>

        <listen type='address' address='0.0.0.0'/>

      </graphics>

      <video>

        <model type='cirrus' vram='9216' heads='1'/>

        <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>

      </video>

      <memballoon model='virtio'>

        <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>

      </memballoon>

    </devices>

  </domain>

</domainsnapshot>

（4)查看当前虚拟机镜像文件，快照文件的路径在/var/lib/libvirt/qemu/snapshot/ 下

[root@KVM qemu]# ll /var/lib/libvirt/qemu/snapshot/hadoop3/
total 8
-rw------- 1 root root 3402 Feb  4 17:17 1454577228.xml
-rw------- 1 root root 3453 Feb  4 17:17 1454577442.xml

4，恢复虚拟机快照

（1）恢复虚拟机快照必须关闭虚拟机

[root@KVM qemu]# virsh list --all

 Id    Name                           State
----------------------------------------------------

 1     win7                           running

 6     hadoop2                        running

 -     hadoop1                        shut off

 -     hadoop3                        shut off

 -     hadoop4                        shut off

（2）确认恢复快照的时间，这里是恢复到1454577442

[root@KVM qemu]# virsh snapshot-list hadoop3       

 Name                 Creation Time             State
------------------------------------------------------------

 1454577228           2016-02-04 17:13:48 +0800 shutoff

 1454577442           2016-02-04 17:17:22 +0800 shutoff

（3）执行恢复，并确认恢复版本

[root@KVM qemu]# virsh snapshot-revert hadoop3 1454577442 

[root@KVM qemu]# virsh snapshot-current hadoop3

5，删除虚拟机快照

（1）查看虚拟机快照

[root@KVM test]# qemu-img info hadoop3.qcow2 
image: hadoop3.qcow2

file format: qcow2
virtual size: 10G (10737418240 bytes)
disk size: 881M
cluster_size: 65536
Snapshot list:
ID        TAG                 VM SIZE                DATE       VM CLOCK
1         1454577228                0 2016-02-04 17:13:48   00:00:00.000
2         1454577442                0 2016-02-04 17:17:22   00:00:00.000

(2)删除快照

[root@KVM test]# virsh snapshot-delete hadoop3 1454577228
Domain snapshot 1454577228 deleted

[root@KVM test]# qemu-img info hadoop3.qcow2             
image: hadoop3.qcow2

file format: qcow2
virtual size: 10G (10737418240 bytes)
disk size: 881M
cluster_size: 65536
Snapshot list:
ID        TAG                 VM SIZE                DATE       VM CLOCK
2         1454577442                0 2016-02-04 17:17:22   00:00:00.000

至此虚拟机快照从创建，查看，删除。如果有报错，再一一的进行拍错。

本文转自 lqbyz 51CTO博客，原文链接:http://blog.51cto.com/liqingbiao/1741125