1、硬件环境检测

grep -E –color ‘vmx|svm’ /proc/cpuinfo

有输出代表cpu支持

2、软件包安装

yum install qemu-kvm qemu-img libvirt-python python-virtinst libvirt-client virt-viewer bridge-utils

—>少了一些组件也可

yum groupinstall -y Virtualization “Virtualization Client” “Virtualization Platform” “Virtualization Tools”

使用桥接网络安装bridge-utils包

yum -y install bridge-utils

3、关闭防火墙对IPv6支持并关闭selinux功能

chkconfig ip6tables off
setenforce 0 临时关闭
sed -i ‘s/SELINUX=enforcing/SELINUX=disabled/g’ /etc/selinux/config

4、查看模块并启动进程

查看KVM模块：lsmod | grep kvm
service libvirtd restart启动libvirt进程
modprobe kvm
modprobe kvm-intel
modprobe -ls | grep kvm

5、将网卡模式修改为桥接模式

首先复制原em1和em2网卡为br1和br2，将em1的配置文件修改为：

DEVICE=”em1“
BOOTPROTO=”static”
HWADDR=”30:85:A9:9F:67:74″
NM_CONTROLLED=”no”
ONBOOT=”yes”
TYPE=”Ethernet”
UUID=”34096e10-ff72-4142-b7b3-e290d200b68a”
BRIDGE=”br1″

命令：virsh iface-bridge em3 br3

虚拟安装脚本create_kvm.sh内容：

virt-install 
–name Test 
–ram 1536 
–vcpus=1 
–disk path=/data/img/kvm_Test.img,size=50 
–network bridge=br0 
–cdrom=/opt/iso/CentOS-6.8-x86_64-minimal.iso 
–accelerate 
–vnclisten=0.0.0.0 
–vncport=5911 
–vnc

启动虚机：

virsh start Test

查看虚拟状态：

virsh list –all

raw转换为qcow2格式：

qemu-img convert -f raw -0 qcow2 /data/img/kvm-Test.img /data/img/kvm-Test.qcow2
确认：
qemu-img info /data/img/kvm-Test.qcow2

修改虚机配置文件：

virsh edit Test

复制（克隆）一台虚拟服务器：

virt-clone -o Test -n Test -f /data/img/kvm-Test1.qcow2

虚机当前运行产生的相关文件所在目录：

/var/run/libvirt/qemu/
/etc/libvirt/qemu配置文件目录
virsh shutdown Test

如果报错，先暂停该虚机业务

virsh suspend Test
cp -av /data/img/kvm-Test1.qcow2  /data/img/kvm-Test2.qcow2
virsh dumpxml Test1 > /etc/libvirt/qemu/Test2.xml
virsh define /etc/libvirt/qemu/Test2.xml

虽然克隆完毕，但我们还不能启动，需编辑配置文件先修改vnc端口

virsh edit Test2

注意：与其他虚拟服务器vnc端口不一致而且要在可用范围内。
保存配置后尝试启动

virsh start Test2

通过vnc viewer连接
ifconfig命令查看后发现没网卡相关信息

more /etc/udev/rules.d/70-persistent-net.rules >>/etc/sysconfig/network-scripts/ifcfg-eth0

然后修改MAC地址和对应IP并注释无关代码后保存

service network restart

重启服务：

service libvirtd restart

再次尝试启动虚拟机Test2（略）

yum install -y acpid
service acpid start
chkconfig acpid on

管理kvm虚拟机

常用的虚拟机管理命令

• 列出所有的虚拟机

1  virsh list --all

• 显示虚拟机信息

1  virsh dominfo kvm-1

• 显示虚拟机内存和cpu的使用情况

1  yum install virt-top -y
2  virt-top

• 显示虚拟机分区信息

1  virt-df kvm-1

• 关闭虚拟机（shutodwn）

1  virsh shutdown kvm-1

• 启动虚拟机

1  virsh start kvm-1

• 设置虚拟机（kvm-1）跟随系统自启

1  virsh autostart kvm-1

• 关闭虚拟及自启

1  virsh autostart --disable kvm-1

• 删除虚拟机

1  virsh undefine kvm-1

• 通过控制窗口登录虚拟机

virsh console kvm-1

给虚拟机添加硬盘

添加硬盘（lvm卷）或者USB到虚拟机上

1  virsh attach-disk kvm-1 /dev/sdb vbd --driver qemu --mode shareable

• 使用完成之后可以卸载usb

1  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
#  2  # 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




 <address />

 Add:




 <address />

 # 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

1  virsh shutdown kvm-1

• 第二步

1  virsh destroy kvm-1

• 第三步

1  virsh undefine kvm-1

• 第四部

1  rm /dev/vg_shkvm1/kvm-1  # 不建议删除硬盘