OpenStact基础之KVM

Posted 2020-11-20

一、前期准备

1.1、开启虚拟机前，CPU要支持虚拟化

查看服务器是否打开对虚拟化的支持：

cat /proc/cpuinfo | grep vmx(intel)

cat /proc/cpuinfo | grep svm(AMD)

任意一个有输出，代表支持虚拟化

[[email protected] ~]# cat /etc/redhat-release

CentOS release 6.8 (Final)

[[email protected] ~]# uname -r

2.6.32-642.el6.x86_64

[[email protected] ~]# getenforce

Disabled

[[email protected] ~]# service iptables status

iptables: Firewall is not running.

[[email protected] ~]# date

Sat Jun 24 19:40:10 CST 2018

[[email protected] ~]# ifconfig eth0

eth0      Link encap:Ethernet  HWaddr 00:0C:29:2B:9F:B1  

         inet addr:10.0.0.101  Bcast:10.0.0.255  Mask:255.255.255.0

         inet6 addr: fe80::20c:29ff:fe2b:9fb1/64 Scope:Link

         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

         RX packets:1238 errors:0 dropped:0 overruns:0 frame:0

         TX packets:569 errors:0 dropped:0 overruns:0 carrier:0

         collisions:0 txqueuelen:1000

         RX bytes:122277 (119.4 KiB)  TX bytes:77114 (75.3 KiB)

[[email protected] ~]# cat  /etc/sysconfig/network

NETWORKING=yes

HOSTNAME=linux-node1

[[email protected] ~]# cat  /etc/hosts

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4

::1       localhost localhost.localdomain localhost6 localhost6.localdomain6

10.0.0.101 linux-node1

10.0.0.102 linux-node2

[[email protected] ~]# ping linux-node1

PING linux-node1 (10.0.0.101) 56(84) bytes of data.

64 bytes from linux-node1 (10.0.0.101): icmp_seq=1 ttl=64 time=0.045 ms

^C

--- linux-node1 ping statistics ---

2 packets transmitted, 2 received, 0% packet loss, time 1896ms

rtt min/avg/max/mdev = 0.042/0.043/0.045/0.006 ms

[[email protected] ~]# ping www.baidu.com

PING www.a.shifen.com (61.135.169.125) 56(84) bytes of data.

64 bytes from 61.135.169.125: icmp_seq=1 ttl=128 time=3.58 ms

64 bytes from 61.135.169.125: icmp_seq=2 ttl=128 time=3.80 ms

^C

--- www.a.shifen.com ping statistics ---

2 packets transmitted, 2 received, 0% packet loss, time 1313ms

rtt min/avg/max/mdev = 3.587/3.697/3.807/0.110 ms

二、安装配置

[[email protected] ~]# yum -y install qemu-kvm qemu-kvm-tools virt-manager libvirt ##qemu工具及管理kvm的工具、虚拟机的创建、用libvirt对虚拟机进行管理

[[email protected] ~]# /etc/init.d/libvirtd start

Starting libvirtd daemon:                                [  OK  ]

[[email protected] ~]# ifconfig virbr0  ##启动后会多出一个virbr0网卡，默认IP为192.168.122.1

virbr0    Link encap:Ethernet  HWaddr 52:54:00:EB:DF:39  

         inet addr:192.168.122.1  Bcast:192.168.122.255  Mask:255.255.255.0

         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

         RX packets:0 errors:0 dropped:0 overruns:0 frame:0

         TX packets:0 errors:0 dropped:0 overruns:0 carrier:0

         ollisions:0 txqueuelen:0

         RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

[[email protected] ~]# brctl show

bridge name  bridge id      STP enabled interfaces  ##STP:二层生成树协议

virbr0  8000.525400ebdf39    yes      virbr0-nic

iptables的变化

[[email protected] ~]# iptables  -nvL

Chain INPUT (policy ACCEPT 179 packets, 16004 bytes)

 pkts bytes target     prot opt in     out     source    destination         

 0  0 ACCEPT     udp  --  virbr0 *   0.0.0.0/0  0.0.0.0/0   udp dpt:53

 0  0 ACCEPT     tcp  --  virbr0 *   0.0.0.0/0  0.0.0.0/0   tcp dpt:53

 0  0 ACCEPT     udp  --  virbr0 *   0.0.0.0/0  0.0.0.0/0   udp dpt:67

 0  0 ACCEPT     tcp  --  virbr0 *   0.0.0.0/0  0.0.0.0/0   tcp dpt:67

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)

 pkts bytes target     prot opt in     out        source     destination         

 0   0 ACCEPT   all  --  *virbr0  0.0.0.0/0   192.168.122.0/24   state RELATED,ESTABLISHED

 0   0 ACCEPT   all  --  virbr0 *  192.168.122.0/24  0.0.0.0/0           

 0   0 ACCEPT   all  --  virbr0 virbr0  0.0.0.0/0    0.0.0.0/0           

 0   0 REJECT   all  --  * virbr0     0.0.0.0/0  0.0.0.0/0   reject-with icmp-port-unreachable

 0   0 REJECT    all  --  virbr0 *   0.0.0.0/0   0.0.0.0/0  reject-with icmp-port-unreachable

Chain OUTPUT (policy ACCEPT 126 packets, 20568 bytes)

 pkts bytes target     prot opt in     out     source              destination

[[email protected] ~]# iptables -t nat -nvL

Chain PREROUTING (policy ACCEPT 345 packets, 26948 bytes)

 pkts bytes target     prot opt in     out     source          destination

Chain POSTROUTING (policy ACCEPT 6 packets, 456 bytes)

 pkts bytes target     prot opt in     out     source              destination

 0   0 MASQUERADE  tcp  --  *  *  192.168.122.0/24  !192.168.122.0/24  masq ports: 1024-65535

 0   0 MASQUERADE  udp  --  *  *  192.168.122.0/24  !192.168.122.0/24  masq ports: 1024-65535

 0   0 MASQUERADE  all  --  *   *  192.168.122.0/24  !192.168.122.0/24    

Chain OUTPUT (policy ACCEPT 6 packets, 456 bytes)

 pkts bytes target     prot opt in    out    source             destination         

[[email protected] ~]# iptables -t mangle -nvL

Chain PREROUTING (policy ACCEPT 556 packets, 45504 bytes)

 pkts bytes target     prot opt in     out     source         destination         

Chain INPUT (policy ACCEPT 200 packets, 17736 bytes)

 pkts bytes target     prot opt in     out     source         destination         

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)

 pkts bytes target     prot opt in     out     source          destination         

Chain OUTPUT (policy ACCEPT 139 packets, 24396 bytes)

 pkts bytes target     prot opt in     out     source          destination         

Chain POSTROUTING (policy ACCEPT 139 packets, 24396 bytes

 pkts bytes target     prot opt in     out     source          destination

 0  0 CHECKSUM   udp  --  *    virbr0  0.0.0.0/0   0.0.0.0/0  udp dpt:68 CHECKSUM fill

[[email protected] ~]# iptables -t raw -nvL

Chain PREROUTING (policy ACCEPT 107 packets, 8554 bytes)

 pkts bytes target     prot opt in     out     source         destination         

Chain OUTPUT (policy ACCEPT 29 packets, 6892 bytes)

 pkts bytes target     prot opt in     out     source         destination

[[email protected] ~]# qemu-img create -f raw /opt/Centos-6.8-x86_64.raw 5G

Formatting '/opt/Centos-6.8-x86_64.raw', fmt=raw size=5368709120

[[email protected] ~]# file /opt/Centos-6.8-x86_64.raw

/opt/Centos-6.8-x86_64.raw: data

[[email protected] ~]# qemu-img info /opt/Centos-6.8-x86_64.raw

image: /opt/Centos-6.8-x86_64.raw

file format: raw    ##文件格式(硬盘)

virtual size: 5.0G (5368709120 bytes)  ##虚拟空间

disk size: 0   ##已用空间

[[email protected] ~]# cd /opt

[[email protected] opt]# rz  CentOS-6.8-x86_64-bin-DVD1.iso

[[email protected] opt]# ls

Centos-6.8-x86_64.raw  rh  CentOS-6.8-x86_64-bin-DVD1.iso

[[email protected] opt]# virt-install --virt-type kvm --name Centos-6.8-x86_64 --ram 512 --cdrom=/opt/CentOS-6.8-x86_64-bin-DVD1.iso --disk path=/opt/Centos-6.8-x86_64.raw --network network=default --graphics vnc,listen=0.0.0.0 --noautoconsole --os-type=linux --os-variant=rhel6

Starting install...

Creatingdomain...                  | 0 B     00:01

Domain installation still in progress. You can reconnect to

the console to complete the installation process.

2.2、用VNC查看:

最后会reboot

[[email protected] opt]# netstat -lntup|grep 5900  ##查看端口，看kvm是否启动

[[email protected] opt]# virsh list --all   ##查看所有的

 Id    Name                      State

----------------------------------------------------

 -     Centos-6.8-x86_64            shut off

[[email protected] opt]# virsh start Centos-6.8-x86_64  ##启动虚拟机

Domain Centos-6.8-x86_64 started

[[email protected] opt]# netstat -lntup|grep 5900

tcp    0    0 0.0.0.0:5900    0.0.0.0:*     LISTEN     3660/qemu-kvm       

在连接VNC时可能会出现“attempting to reconnect to VNC Server Zlibinstream:inflate faild”

解决办法如下:

在VNC中操作KVM:

此时在宿主机上查看(虚拟机默认为NAT模式):

[[email protected] opt]# brctl show

bridge name bridge id  STP enabled interfaces

virbr0  8000.525400ebdf39 yes  virbr0-nic

                    vnet0  ##虚机的网卡，绑定在virbr0上

改为桥接模式

[[email protected] opt]# brctl addbr br0

[[email protected] opt]# brctl show

bridge name bridge id  STP enabled  interfaces

br0  8000.000000000000 no  

virbr0 8000.525400ebdf39 yes     virbr0-nic

                       vnet0

[[email protected] opt]# brctl addif br0 eth0

[[email protected] ~]# brctl addbr br0 && brctl addif br0 eth0 && ip addr del dev eth0 10.0.0.101/24 && ifconfig br0 10.0.0.101/24 up ##这种方法可以避免改网卡失联

[[email protected] ~]# virsh edit Centos-6.8-x86_64

    <interface type='bridge'>

      <mac address='52:54:00:cc:e1:18'/>

      <source bridge='br0'/>

[[email protected] ~]# ps -ef|grep kvm

[[email protected] ~]# kill 4261

[[email protected] ~]# virsh start Centos-6.8-x86_64

[[email protected] ~]# virsh destroy Centos-6.8-x86_64  ##这种重启方法好一些，上种粗暴一些

[[email protected] ~]# virsh start Centos-6.8-x86_64

[[email protected] ~]# virsh list --all

[[email protected] ~]# brctl show

bridge name bridge id     STP enabled  interfaces

br0  8000.000c292b9fb1 no           eth0

                          vnet0

virbr0  8000.525400ebdf39    yes          virbr0-nic

通过VNC登录KVM虚拟机