KVM虚拟化笔记（九）------kvm虚拟机快照备份

   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

<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'/>

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。