Linux下KVM虚拟机基本管理及常用命令（转）

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发布时间：2019-06-14

本文共 8671 字，大约阅读时间需要 28 分钟。

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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Kvm虚拟机默认配置文件位置

[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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Create a 10-GB non-sparse file:

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

Shutdown the VM:
# virsh shutdown vm1

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
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删除虚拟机