CAS KVM 虚拟机的保护与恢复

目录

• 目录
• 方式一
• 方式二

方式一

思路：以 QCOW2 格式来备份和恢复被保护的 KVM 虚拟机

• Step1：centos7_0(base qcow2) 以 qcow2 格式写入到 iSCSI 设备

root@h3cas-e306:/vms/images# virsh list --all
 Id    Name                           State
----------------------------------------------------
 33    centos7                        running
root@h3cas-e306:/vms/images# virsh domblklist centos7
Target     Source
------------------------------------------------
vda        /vms/images/centos7_0
hda        /vms/isos/CentOS-7-x86_64-Minimal-1511.iso
root@h3cas-e306:/vms/images# qemu-img convert -f qcow2 /vms/images/centos7_0 -O qcow2 /dev/sdd
root@h3cas-e306:/vms/images# qemu-img info /dev/sdd
image: /dev/sdd
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 0
cluster_size: 262144
Format specific information:
    compat: 1.1
    lazy refcounts: false

• Step2：尝试使用 iSCSI 设备手动启动 KVM 虚拟机

# 创建 XML 文件
root@h3cas-e306:/etc/libvirt/qemu# vim centos7_q_0.xml

<domain type='kvm'>
  <name>centos7_q_0</name>
  <uuid>d668e699-22a4-464b-99c4-1ffdcd6ad4e1</uuid>
  <osha>0</osha>
  <timesync>0</timesync>
  <automem>0</automem>
  <memory unit='KiB'>4194304</memory>
  <currentMemory unit='KiB'>4194304</currentMemory>
  <memorySlots>10</memorySlots>
  <maxMemory unit='KiB'>34359738368</maxMemory>
  <blkiotune>
    <weight>300</weight>
  </blkiotune>
  <memtune>
    <priority>1</priority>
  </memtune>
  <memoryBacking>
    <locked>0</locked>
  </memoryBacking>
  <vcpu placement='static' current='2'>24</vcpu>
  <cputune>
    <shares>512</shares>
    <period>1000000</period>
    <quota>-1</quota>
  </cputune>
  <os>
    <type arch='x86_64' machine='pc-i440fx-2.1'>hvm</type>
    <system>linux</system>
    <boot dev='hd'/>
    <boot dev='cdrom'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <pae/>
  </features>
  <cpu>
    <topology sockets='24' cores='1' threads='1'/>
    <numa>
      <cell cpus='0-1' memory='4194304'/>
    </numa>
    <gurantee unit='MHz'>0</gurantee>
  </cpu>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <pm>
    <suspend-to-mem enabled='no'/>
    <suspend-to-disk enabled='no'/>
  </pm>
  <tools upgrade='auto'/>
  <devices>
    <emulator>/usr/bin/kvm</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2' cache='directsync' io='native'/>
      <source file='/dev/sdd'/>
      <target dev='vda' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x08' function='0x0'/>
    </disk>
    <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw' cache='none'/>
      <target dev='hdc' bus='ide'/>
      <readonly/>
      <address type='drive' controller='0' bus='1' target='0' unit='0'/>
    </disk>
    <controller type='usb' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
    </controller>
    <controller type='pci' index='0' model='pci-root'/>
    <controller type='ide' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
    </controller>
    <controller type='virtio-serial' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </controller>
    <serial type='pty'>
      <target port='0'/>
    </serial>
    <console type='pty'>
      <target type='serial' port='0'/>
    </console>
    <channel type='unix'>
      <source mode='bind' path='/var/lib/libvirt/qemu/centos7.agent'/>
      <target type='virtio' name='org.qemu.guest_agent.0'/>
      <address type='virtio-serial' controller='0' bus='0' port='1'/>
    </channel>
    <input type='tablet' bus='usb'/>
    <input type='mouse' bus='ps2'/>
    <graphics type='vnc' port='-1' autoport='yes' 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='0x09' function='0x0'/>
    </memballoon>
  </devices>


root@h3cas-e306:/etc/libvirt/qemu# virsh define centos7_q_0.xml
Domain centos7_q_0 defined from centos7_q_0.xml

root@h3cas-e306:/etc/libvirt/qemu# virsh list --all
 Id    Name                           State
----------------------------------------------------
 33    centos7                        running
 -     centos7_q_0                    shut off

root@h3cas-e306:/etc/libvirt/qemu# virsh start centos7_q_0
Domain centos7_q_0 started

root@h3cas-e306:/etc/libvirt/qemu# virsh list --all
 Id    Name                           State
----------------------------------------------------
 33    centos7                        running
 34    centos7_q_0                    running

• Step3：对 centos7_0 做快照得到增量快照数据 centos7_1(increment qcow2)

root@h3cas-e306:/vms/images# virsh snapshot-create-as --domain centos7 snap01 snap01-desc --disk-only --diskspec vda,snapshot=external,file=/vms/images/centos7_1 --atomic
Domain snapshot snap01 created
root@h3cas-e306:/vms/images# l
centos7_0  centos7_1
root@h3cas-e306:/vms/images# qemu-img info centos7_1
image: centos7_1
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 772K
cluster_size: 262144
backing file: /vms/images/centos7_0
backing file format: qcow2
Format specific information:
    compat: 1.1
    lazy refcounts: false
root@h3cas-e306:/vms/images# virsh domblklist centos7
Target     Source
------------------------------------------------
vda        /vms/images/centos7_1
hda        /vms/isos/CentOS-7-x86_64-Minimal-1511.iso

NOTE: 现在虚拟机的数据会写入到 centos7_1 中, centos7_0 理论上应该是只读的.

• Step4：Copy centos7_1 的副本到备份目录下

root@h3cas-e306:/vms/images# cp centos7_1 /kvm_backup/
root@h3cas-e306:/vms/images# ll /kvm_backup/
total 2572
drwxr-xr-x  2 root root    4096 Apr 18 23:39 ./
drwxr-xr-x 33 root root    4096 Apr 18 23:22 ../
-rw-------  1 root root 2883584 Apr 18 23:39 centos7_1

• Step5：rebase 并 commit centos7_1 到 iSCSI 设备中

root@h3cas-e306:/etc/libvirt/qemu# virsh destroy 34
Domain 34 destroyed
root@h3cas-e306:/etc/libvirt/qemu# virsh list --all
 Id    Name                           State
----------------------------------------------------
 33    centos7                        running
 -     centos7_q_0                    shut off
root@h3cas-e306:/vms/images# cd /kvm_backup/
root@h3cas-e306:/kvm_backup# ls
centos7_1
root@h3cas-e306:/kvm_backup# qemu-img info centos7_1
image: centos7_1
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 2.5M
cluster_size: 262144
backing file: /vms/images/centos7_0
backing file format: qcow2
Format specific information:
    compat: 1.1
    lazy refcounts: false
root@h3cas-e306:/kvm_backup# qemu-img info /dev/sdd
image: /dev/sdd
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 0
cluster_size: 262144
Format specific information:
    compat: 1.1
    lazy refcounts: false
root@h3cas-e306:/kvm_backup# qemu-img rebase -b /dev/sdd -F qcow2 centos7_1
root@h3cas-e306:/kvm_backup# qemu-img info centos7_1
image: centos7_1
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 15M
cluster_size: 262144
backing file: /dev/sdd
backing file format: qcow2
Format specific information:
    compat: 1.1
    lazy refcounts: false
root@h3cas-e306:/kvm_backup# qemu-img info /dev/sdd
image: /dev/sdd
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 0
cluster_size: 262144
Format specific information:
    compat: 1.1
    lazy refcounts: false
root@h3cas-e306:/kvm_backup# qemu-img commit -f qcow2 centos7_1
Image committed.
root@h3cas-e306:/kvm_backup# qemu-img info centos7_1
image: centos7_1
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 15M
cluster_size: 262144
backing file: /dev/sdd
backing file format: qcow2
Format specific information:
    compat: 1.1
    lazy refcounts: false
root@h3cas-e306:/kvm_backup# qemu-img info /dev/sdd
image: /dev/sdd
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 0
cluster_size: 262144
Format specific information:
    compat: 1.1
    lazy refcounts: false

• Step6：使用 commit 后的 iSCSI 设备启动虚拟机

root@h3cas-e306:/etc/libvirt/qemu# virsh list --all
 Id    Name                           State
----------------------------------------------------
 33    centos7                        running
 -     centos7_q_0                    shut off

root@h3cas-e306:/etc/libvirt/qemu# virsh start centos7_q_0
Domain centos7_q_0 started

root@h3cas-e306:/etc/libvirt/qemu# virsh list --all
 Id    Name                           State
----------------------------------------------------
 33    centos7                        running
 35    centos7_q_0                    running

NOTE: 虚拟机启动成功, 证明 QCOW2 格式的虚拟机增量快照文件是能够合并到虚拟机 Base 数据文件中的。

方式二

思路：以 RAW 格式来备份和恢复被保护的 KVM 虚拟机

• Step1：centos7(base qcow2) 以 raw 格式写入到 iSCSI 设备

root@h3cas-e306:/vms/images# qemu-img info centos7
image: centos7
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 1.0G
cluster_size: 262144
Format specific information:
    compat: 1.1
    lazy refcounts: false
root@h3cas-e306:/vms/images# qemu-img convert -f qcow2 /vms/images/centos7 -O raw /dev/sdd
root@h3cas-e306:/vms/images# qemu-img info /dev/sdd
image: /dev/sdd
file format: raw
virtual size: 23G (24696061952 bytes)
disk size: 0

• Step2：使用 iSCSI 设备手动启动 KVM 虚拟机

root@h3cas-e306:/etc/libvirt/qemu# virsh define centos7_r_0.xml
Domain centos7_r_0 defined from centos7_r_0.xml
root@h3cas-e306:/etc/libvirt/qemu# virsh list --all
 Id    Name                           State
----------------------------------------------------
 36    centos7                        running
 -     centos7_q_0                    shut off
 -     centos7_r_0                    shut off
root@h3cas-e306:/etc/libvirt/qemu# virsh start centos7_r_0
Domain centos7_r_0 started
root@h3cas-e306:/etc/libvirt/qemu# virsh list --all
 Id    Name                           State
----------------------------------------------------
 36    centos7                        running
 37    centos7_r_0                    running
 -     centos7_q_0                    shut off

• Step3：对 centos7 做快照得到增量快照数据 centos7_1(increment qcow2)

root@h3cas-e306:/vms/images# virsh snapshot-create-as --domain centos7 snap01 snap01-desc --disk-only --diskspec vda,snapshot=external,file=/vms/images/centos7_1 --atomic
Domain snapshot snap01 created
root@h3cas-e306:/vms/images# ls
centos7  centos7_1
root@h3cas-e306:/vms/images# qemu-img info centos7_1
image: centos7_1
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 2.0M
cluster_size: 262144
backing file: /vms/images/centos7
backing file format: qcow2
Format specific information:
    compat: 1.1
    lazy refcounts: false

• Step4： Copy centos7_1 的副本到备份目录下

root@h3cas-e306:/vms/images# cp centos7_1 /kvm_backup/
root@h3cas-e306:/vms/images# cd /kvm_backup/
root@h3cas-e306:/kvm_backup# ls
centos7_1
root@h3cas-e306:/kvm_backup#  qemu-img info  /kvm_backup/centos7_1
image: /kvm_backup/centos7_1
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 2.5M
cluster_size: 262144
backing file: /vms/images/centos7
backing file format: qcow2
Format specific information:
    compat: 1.1
    lazy refcounts: false
root@h3cas-e306:/kvm_backup# qemu-img info /dev/sdd
image: /dev/sdd
file format: raw
virtual size: 23G (24696061952 bytes)
disk size: 0

• Step5：以 raw 的格式 rebase 并 commit centos7_1 到 iSCSI 设备中

root@h3cas-e306:/kvm_backup# qemu-img rebase -b /dev/sdd -F raw centos7_1
root@h3cas-e306:/kvm_backup# qemu-img info centos7_1
image: centos7_1
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 25M
cluster_size: 262144
backing file: /dev/sdd
backing file format: raw
Format specific information:
    compat: 1.1
    lazy refcounts: false
root@h3cas-e306:/kvm_backup# qemu-img info /dev/sdd
image: /dev/sdd
file format: raw
virtual size: 23G (24696061952 bytes)
disk size: 0
root@h3cas-e306:/kvm_backup# qemu-img commit -f qcow2 centos7_1
Image committed.
root@h3cas-e306:~# qemu-img info /dev/sdd
image: /dev/sdd
file format: raw
virtual size: 23G (24696061952 bytes)
disk size: 0

• Step6： 使用 commit 后的 iSCSI 设备再次启动虚拟机

root@h3cas-e306:/etc/libvirt/qemu# virsh list --all
 Id    Name                           State
----------------------------------------------------
 38    centos7                        running
 -     centos7_q_0                    shut off
 -     centos7_r_0                    shut off

root@h3cas-e306:/etc/libvirt/qemu# virsh start centos7_r_0
Domain centos7_r_0 started

root@h3cas-e306:/etc/libvirt/qemu# virsh list --all
 Id    Name                           State
----------------------------------------------------
 38    centos7                        running
 39    centos7_r_0                    running
 -     centos7_q_0                    shut off

NOTE：尚未测试虚拟机在备份和恢复的过程中虚拟机的应用业务是否被中断。