安装kvm

文档参考：
CentOS7 ：http://www.linux-kvm.org/page/HOWTO#RHEL.2FCentOS_7
CentOS6 ：https://wiki.centos.org/zh/HowTos/KVM --> 白皮书: 第一册，第二册

1.a,创建虚拟机
1.b,运行/停止虚拟机
1.c,查看虚拟机

虚拟机配置调整：内存，磁盘，cpu数
虚拟机的两大主要文件：image, xml文件

1, image路径：
root@controller:/var/lib/libvirt/images# ls
cent7-clone.qcow2 cent7.qcow2 centos7.0.qcow2

2, 虚拟机xml配置文件路径：
root@controller:/etc/libvirt/qemu# ls
cent7-clone.xml cent7.xml centos7.0.xml networks

1, 虚拟机：生命周期管理

a，创建虚拟机 (virt-install)

内存：1G, cup: 2, 硬盘:30G
执行命令后，满足条件就会弹出centos的安装界面
virt-install \
—name c6 \
—ram=1024 \
—vcpus=2 \
—network=bridge:br0 \
—disk path=/var/lib/libvirt/images/c6.img,size=30 \
—cdrom /CentOS-6.10-x86_64-minimal.iso
b,查看/运行/停止虚拟机 (virsh list/ start/ shutdown,destroy)

root@controller:/home/wang# virsh list

Id Name State
6 centos7.0 running
9 cent7 running

root@controller:~/openstack# virsh dominfo cent7
Id: 20
Name: cent7
UUID: a566d8e4-ec6f-42d7-9d31-8d0d3ce5f09a
OS Type: hvm
State: running
CPU(s): 2
CPU time: 197.0s
Max memory: 2097152 KiB
Used memory: 1048576 KiB
Persistent: yes
Autostart: disable
Managed save: no
Security model: apparmor
Security DOI: 0
Security label: libvirt-a566d8e4-ec6f-42d7-9d31-8d0d3ce5f09a (enforcing)

########### autostart, start, shutdown, reboot //pause, resume
root@controller:/etc/network# virsh shutdown cent7
Domain cent7 is being shutdown

root@controller:/etc/network# virsh list —all

Id Name State
6 centos7.0 running
- cent7 shut off
3, 删除虚拟机

root@controller:/ # cat /usr/local/bin/kvm-delete.sh
read -p ‘输入(要删除的虚拟机)：’ name
echo “….going to delete ..$name”

1,destroy
virsh destroy $name

2,undefine
virsh undefine $name

3,del image
rm -f /var/lib/libvirt/images/$name.qcow2
echo “delete kvm $name —> ok….”

2, kvm登录虚拟机

virsh console xx

virt-viewer -c qemu:///system VMachinename
virt-viewer cent7

3, 虚拟机内存调整

## setmaxmem                      change maximum memory limit
## setmem                            change memory allocation
#虚拟机开机后，动态内存扩展(加上--config表示写入到配置文件，永久生效)
virsh setmaxmem centos7  9GB --config
virsh  setmem centos7    8GB  --config
## setvcpus                       change number of virtual CPUs
## setvcpu                        attach/detach vcpu or groups of threads

4, 复制/克隆虚拟机

virt-clone命令：需要关闭虚拟机再操作

root@controller:~/openstack# virt-clone -o cent7 -n cent7_2 --auto-clone
正在分配 'cent7_2.qcow2'                                                                                           | 5.0 GB  00:00:23     
成功克隆 'cent7_2'。
root@controller:~/openstack# virsh list --all
 Id    Name                           State
----------------------------------------------------
 18    stack                          running
 -     cent7                          shut off
 -     cent7_2                        shut off
root@controller:~/openstack# ls /var/lib/libvirt/images/
cent7_2.qcow2  cent7.qcow2  centos7.0.qcow2  stack.qcow2
root@controller:~/openstack# ls /etc/libvirt/qemu
cent7_2.xml  cent7.xml  networks  stack.xml

若没有关闭虚拟机来克隆就会报以下错误：

root@controller:~# virsh list
 Id    Name                           State
----------------------------------------------------
 11    centos7.0                      running
 12    cent7                          paused
root@controller:~# virt-clone -o cent7 --auto-clone
WARNING  设置图形设备端口为自动端口，以避免相互冲突。
ERROR    Couldn't create storage volume 'cent7-clone.qcow2': 'internal error: Child process (/usr/bin/qemu-img convert -f qcow2 -O qcow2 -o compat=1.1,lazy_refcounts /var/lib/libvirt/images/cent7.qcow2 /var/lib/libvirt/images/cent7-clone.qcow2) unexpected exit status 1: qemu-img: Could not open '/var/lib/libvirt/images/cent7.qcow2': Failed to get shared "write" lock
Is another process using the image?

5,虚拟机重命名

把上面的cent7-clone 这个刚克隆的虚拟机重命名(先停止虚拟机）–> cent7_2

root@controller:~# virt-clone -o cent7 --auto-clone
正在分配 'cent7-clone.qcow2'                                                                                       |  40 GB  00:00:47     
成功克隆 'cent7-clone'。
#启动克隆好的虚拟机
root@controller:~# virsh  start cent7
Domain cent7 started
root@controller:~# virsh  start cent7-clone
Domain cent7-clone started
root@controller:~# virsh list
 Id    Name                           State
----------------------------------------------------
 11    centos7.0                      running
 13    cent7                          running
 14    cent7-clone                    running
# 1, xml修改
root@controller:~# virsh dumpxml cent7-clone > /etc/libvirt/qemu/cent7_2.xml
root@controller:/etc/libvirt/qemu# ls
cent7_2.xml  cent7-clone.xml  cent7.xml    networks
####修改旧的名字， 为新的名字
root@controller:/etc/libvirt/qemu# grep cent7-clone cent7_2.xml 
  <name>cent7-clone</name>
      <source file='/var/lib/libvirt/images/cent7-clone.qcow2'/>
root@controller:/etc/libvirt/qemu# sed -i s/cent7-clone/cent7_2/g cent7_2.xml 
# 2, image文件重命名
root@controller:/var/lib/libvirt/images# ls
cent7-clone.qcow2  cent7.qcow2 
root@controller:/var/lib/libvirt/images# mv cent7-clone.qcow2 cent7_2.qcow2
# 3,  废弃旧的虚拟机，使用新的虚拟机
root@controller:~# virsh list
 Id    Name                           State
----------------------------------------------------
 13    cent7                          running
 14    cent7-clone                    running
root@controller:~# virsh  shutdown  cent7-clone
Domain cent7-clone is being shutdown
root@controller:/etc/libvirt/qemu# virsh undefine cent7-clone  
Domain cent7-clone has been undefined
root@controller:/etc/network# ls /etc/libvirt/qemu/
cent7_2.xml    cent7.xml      centos7.0.xml  networks/  
root@controller:/etc/libvirt/qemu# virsh list --all
 Id    Name                           State
----------------------------------------------------
 13    cent7                          running
root@controller:/etc/libvirt/qemu# virsh define cent7_2.xml
Domain cent7_2 defined from cent7_2.xml
root@controller:/etc/libvirt/qemu# virsh start cent7_2
viDomain cent7_2 started
root@controller:/etc/libvirt/qemu# virsh list
 Id    Name                           State
----------------------------------------------------
 13    cent7                          running
 15    cent7_2                        running