转载连接：https://www.cnblogs.com/EasonJim/p/8367022.html

一、KVM的基本管理

1、查看KVM虚拟机配置文件

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[root@kvm qemu]# pwd
/etc/libvirt/qemu
[root@kvm qemu]# ll
total 12
-rw------- 1 root root 3863 Nov 6 17:26 CentOS6.5.xml
-rw------- 1 root root 3771 Nov 7 00:57 CentOS6u7.xml
-rw------- 1 root root 3628 Nov 7 02:04 centos.xml
drwx------ 3 root root 40 Nov 7 00:46 networks
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2、启动与关闭

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显示正在运行的虚拟机

[root@kvm ~]# virsh list
Id Name State

显示所有虚拟机

[root@kvm ~]# virsh list --all
Id Name State

• centos                         shut off
  

• CentOS6.5                      shut off
  

• CentOS6u7                      shut off
  

启动名字为CentOS6.5的虚拟机

[root@kvm ~]# virsh start CentOS6.5

关闭名字为CentOS6.5的虚拟机

[root@kvm ~]# virsh shutdown CentOS6.5

强制关闭名字为Centos6.5的虚拟机

[root@kvm ~]# virsh destroy CentOS6.5

移除名字为CentOS6.5的虚拟机

[root@kvm ~]# virsh undefine CentOS6.5

设置CentOS6.5虚拟机开机启动

[root@kvm ~]# virsh autostart CentOS6.5

默认情况下virsh工具不能对linux虚拟机进行关机操作

linux操作系统需要开启与启动acpid服务。在安装KVM linux虚拟机必须配置此服务。

yum -y install acpid

/etc/init.d/acpid start

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3、通过配置文件启动虚拟机

[root@kvm ~]# virsh create /etc/libvirt/qemu/CentOS6.5.xml
4、其它（挂起，恢复）virsh命令

挂起服务器

[root@kvm qemu]# virsh suspend CentOS6.5

恢复服务器

[root@kvm qemu]# virsh resume CentOS6.5
5、重命名虚拟机

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停止虚拟机

[root@kvm qemu]# virsh shutdown CentOS6u5

导出虚拟机的配置文件

[root@kvm qemu]# pwd
/etc/libvirt/qemu
[root@kvm qemu-img]# virsh dumpxml CentOS6u5 > test-CentOS6u5.xml

更改配置文件

[root@kvm qemu]# sed -i 's/CentOS6u5/test-CentOS6u5/g' test-CentOS6u5.xml

注 可以不用更改镜像名

移除原有的虚拟机

[root@kvm qemu]# virsh undefine CentOS6u5

加载新建的虚拟机

[root@kvm qemu]# virsh define test-CentOS6u5.xml

启动虚拟机

[root@kvm qemu]# virsh start test-CentOS6u5
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6、虚拟机创建快照

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转换磁盘镜像文件格式为qcow2

[root@kvm ~]# virsh shutdown test-CentOS6u5
[root@kvm qemu-img]# qemu-img convert -f raw CentOS6u5.raw -O qcow2 CentOS6u5.raw.qcow2

快照一定需要qcow2格式才行

我这边从新建立一个虚拟机以qcow2

创建快照

[root@kvm qemu-img]# virsh snapshot-create CentOS6u5

查看快照

[root@kvm qemu-img]# virsh snapshot-list CentOS6u5
Name Creation Time State

1479043349 2016-11-13 08:22:29 -0500 shutoff

恢复快照

[root@kvm qemu-img]# virsh snapshot-revert CentOS6u5 1479043349

删除快照

[root@kvm qemu-img]# virsh snapshot-delete CentOS6u5 1479043349
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二、常用命令

列出所有的虚拟机

virsh list --all
显示虚拟机信息

virsh dominfo kvm-1
显示虚拟机内存和cpu的使用情况

yum install virt-top -y
virt-top
显示虚拟机分区信息

virt-df kvm-1
关闭虚拟机（shutodwn）

virsh shutdown kvm-1
启动虚拟机

virsh start kvm-1
设置虚拟机（kvm-1）跟随系统自启

virsh autostart kvm-1
关闭虚拟及自启

virsh autostart --disable kvm-1
删除虚拟机

virsh undefine kvm-1
通过控制窗口登录虚拟机

virsh console kvm-1
其它

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virsh shutdown centos 关闭centos虚拟机
virsh destroy centos 强制关闭centos虚拟机
virsh suspend centos 暂停centos虚拟机
vrish resume centos 恢复centos虚拟机
virsh reboot centos 重启centos虚拟机
virsh edit centos 编辑centos虚拟机
virsh vncdisplay centos vnc显示
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给虚拟机添加硬盘

添加硬盘（lvm卷）或者USB到虚拟机上

virsh attach-disk kvm-1 /dev/sdb vbd --driver qemu --mode shareable
使用完成之后可以卸载usb

virsh detach-disk kvm vdb
添加lvm卷，并挂载

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[root@sh-kvm-1 ~]# lvcreate -n kvm-1-data -L 50G vg_shkvm1
[root@sh-kvm-1 ~]# virsh attach-disk kvm-1 /dev/vg_shkvm1/kvm-1-data vdb --driver qemu --mode shareable
Disk attached successfully

登录到kvm-1上查看lvm是否已经被挂载

[root@sh-kvm-1 ~]# virsh console kvm-1 # 输入kvm-1的用户和密码
[root@sh-kvm-1-1 ~]# fdisk -l # 查看硬盘挂载情况

Disk /dev/vda: 21.5 GB, 21474836480 bytes
16 heads, 63 sectors/track, 41610 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00058197

Device Boot Start End Blocks Id System
/dev/vda1 * 3 1018 512000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/vda2 1018 41611 20458496 8e Linux LVM
Partition 2 does not end on cylinder boundary.

Disk /dev/mapper/VolGroup-lv_root: 18.8 GB, 18798870528 bytes
255 heads, 63 sectors/track, 2285 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/mapper/VolGroup-lv_swap: 2147 MB, 2147483648 bytes
255 heads, 63 sectors/track, 261 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/vdb: 53.7 GB, 53687091200 bytes # 新添加的硬盘
16 heads, 63 sectors/track, 104025 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
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格式化新添加的vdb，并添加到lvm组中

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对新添加的硬盘分区

[root@sh-kvm-1-1 ~]# fdisk /dev/vdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xf04b6807.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').

Command (m for help): m # 查看帮助
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition
l list known partition types
m print this menu
n add a new partition
o create a new empty DOS partition table
p print the partition table
q quit without saving changes
s create a new empty Sun disklabel
t change a partition's system id
u change display/entry units
v verify the partition table
w write table to disk and exit
x extra functionality (experts only)
Command (m for help): n #添加一个分区
Command action
e extended
p primary partition (1-4)
p #选择添加一个扩展分区
Partition number (1-4):
Value out of range.
Partition number (1-4): 1
First cylinder (1-104025, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-104025, default 104025):
Using default value 104025

Command (m for help): t #改变分区的格式
Selected partition 1
Hex code (type L to list codes): 8e #改成lvm
Changed system type of partition 1 to 8e (Linux LVM)

Command (m for help): w # 保存更改
root@sh-kvm-1-1 ~]# mkfs.ext4 /dev/vdb1 # 格式化分区
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
3276800 inodes, 13107142 blocks
655357 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
400 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424

Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 28 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@sh-kvm-1-1 ~]# pvc reate /dev/vdb1 # 创建pv
vdb vdb1
[root@sh-kvm-1-1 ~]# vgextend VolGroup /dev/vdb # 扩展lvm vg
vdb vdb1
[root@sh-kvm-1-1 ~]# vgs
VG #PV #LV #SN Attr VSize VFree
VolGroup 2 2 0 wz--n- 69.50g 50.00g

从上面能看出，新添加的 已经加到lvm组中

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改变虚拟机的参数

通过命令行更改创建之后虚拟机的内存，cpu等信息

更改内存

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1. 查看虚拟机当前内存

[root@sh-kvm-1 ~]# virsh dominfo kvm-1 | grep memory
Max memory: 4194304 KiB
Used memory: 4194304 KiB

2、动态设置内存为512MB，内存减少

virsh setmem kvm-1 524288

注意单位必须是KB

3、查看内存变化

virsh dominfo kvm-1 | grep memory

Max memory: 14194304 KiB
Used memory: 524288 kiB

4、内存增加

virsh shutdown kvm-1
virsh edit kvm-1 # 直接更改memory
virsh create /etc/libvirt/demu/kvm-1/xml

之后操作1,2,3步骤增加内存

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更改CPU

需要修改配置文件，因此需要停止虚拟机

virsh shutdown kvm-1
virsh edit kvm-1

2 # 4 > 2

virsh create /etc/libvirt/demu/kvm-1/xml
硬盘扩容

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1. Create a 10-GB non-sparse file:

dd if=/dev/zero of=/vm-images/vm1-add.img bs=1M count=10240

2. Shutdown the VM:

virsh shutdown vm1

3. Add an extra entry for ‘disk’ in the VM's XML file in /etc/libvirt/qemu. You can look copy & paste the entry for your mail storage device and just change the target and address tags. For example:

virsh edit vm1

Add:

# 这里建议使用上面的添加硬盘的方式添加 复制代码 删除虚拟机

第一步，停掉虚拟机

virsh shutdown kvm-1
第二步

virsh destroy kvm-1
第三步

virsh undefine kvm-1
第四步

rm /dev/vg_shkvm1/kvm-1 # 不建议删除硬盘

参考：

https://www.cnblogs.com/yexiaochong/p/6059956.html（以上内容部分转自此篇文章）

http://blog.csdn.net/wh211212/article/details/74908390（以上内容部分转自此篇文章）

http://www.mamicode.com/info-detail-1715145.html