Linux下KVM虚拟机基本管理及常用命令（转）

说明：可能有重复

一、KVM的基本管理

1、查看KVM虚拟机配置文件

#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

2、启动与关闭

#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

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

#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

6、虚拟机创建快照

#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

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

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 

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

[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

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

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

# 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

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

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

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