kvm 基本运维命令

Kvm基本命令

一、查询命令

1.列出所有的虚拟机

virsh list –all

2.显示虚拟机信息

virsh dominfo kvm-1

3.显示虚拟机内存和cpu的使用情况

yum install virt-top -y

virt-top

4.显示虚拟机分区信息

virt-df kvm-1

5.关闭虚拟机（shutodwn）

virsh shutdown kvm-1

6.启动虚拟机

virsh start kvm-1

7.设置虚拟机（kvm-1）跟随系统自启

virsh autostart kvm-1

8. 关闭虚拟及自启

virsh autostart --disable kvm-1

9.删除虚拟机

(当在安装虚拟机中系统过程中，没有安装成功，必须是删除了才能重新安装，不然会一直调用系统、驱动、空磁盘文件)

virsh undefine kvm-1

9.1. 查看列表定位要删除的虚拟机

virsh list –all

9.2.强制停止虚拟机

virsh destroy vm4

9.3. 删除虚拟机

virsh undefined  vm4

9.4. 更新当前文件，并查找包含虚拟机vm4的所有内容

updatedb

9.5. 删除和vm4一切相关的内容

9.6. 更新本机文件后继续查找，确保vm4相关文件彻底删除

10.通过控制窗口登录虚拟机

virsh console kvm-1

二、给虚拟机添加硬盘

1.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

2. 添加lvm卷，并挂载

[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

3. 格式化新添加的vdb，并添加到lvm组中

# 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

三、改变虚拟机的参数

1.通过命令行更改创建之后虚拟机的内存，cpu等信息

1.1更改内存

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

2. 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

#  <vcpu>2</vcpu>  # 4 > 2

virsh create /etc/libvirt/demu/kvm-1/xml

3. 硬盘扩容

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

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

<driver name='qemu' type='raw' cache='none' io='threads'/>

<source file='/vm-images/vm1.img'/>

<target dev='vda' bus='virtio'/>

<address type='pci' domain='0x0000' bus='0x00' slot='0x04'

function='0x0'/>

</disk>

Add:

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

<driver name='qemu' type='raw' cache='none' io='threads'/>

<source file='/vm-images/vm1-add.img'/>

<target dev='vdb' bus='virtio'/>

<address type='pci' domain='0x0000' bus='0x00' slot='0x06'

function='0x0'/>

</disk>

# 这里建议使用上面的添加硬盘的方式添加