KVM是Kernel-based Virtual Machine的简称,是一个开源的虚拟化模块,今天我将在CentOS7的操作系统上安装KVM
一.环境信息
系统: CentOS 7.7 IP: 10.0.0.41/24
在虚拟机安装时,需要启用CPU的虚拟化功能
二. KVM安装步骤
1. 安装qemu-kvm和libvirt
#qemu-kvm用来创建虚拟机硬盘,libvirt用来管理虚拟机
[root@c7-41 ~]# yum install -y qemu-kvm libvirt2. 安装virt-install
#用来创建虚拟机
[root@c7-41 ~]# yum install -y virt-install3. 启动libvirtd,并将它设为开机启动,
#启动后使用ifconfig查看,发现会多出来一块virbr0的网卡,ip默认为192.168.122.1/24,说明libvirtd启动成功,如果默认没有ifconfig命令,使用yum install -y net-tools安装
[root@c7-41 ~]# systemctl start libvirtd && systemctl enable libvirtd
[root@c7-41 ~]# ifconfig
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.0.0.41 netmask 255.255.255.0 broadcast 10.0.0.255
inet6 fe80::20c:29ff:fe49:48c7 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:49:48:c7 txqueuelen 1000 (Ethernet)
RX packets 35522 bytes 50991746 (48.6 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 5373 bytes 579842 (566.2 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ens37: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.16.1.41 netmask 255.255.0.0 broadcast 172.16.255.255
inet6 fe80::20c:29ff:fe49:48d1 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:49:48:d1 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 14 bytes 1016 (1016.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255
ether 52:54:00:0b:43:69 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0经过以上三步,KVM安装成功,下面开始使用KVM创建虚拟机.
三. 使用KVM创建虚拟机(Centos7)
1. 使用qemu命令创建一个10G的硬盘
#最小10,G,可以更多,硬盘的名称为: CentOS-7-x86_64.raw
[root@c7-41 ~]# qemu-img create -f raw /opt/CentOS-7-x86_64.raw 10G
Formatting '/opt/CentOS-7-x86_64.raw', fmt=raw size=10737418240
[root@c7-41 ~]# ll -h /opt
total 0
-rw-r--r-- 1 root root 10G May 9 18:03 CentOS-7-x86_64.raw2. 使用virt-install创建名称为CentOS-7-x86_64的虚拟机
#在创建之前,先上传一个CentOS7的ISO镜像,最好在根目录下创建一个ISO的目录文件夹
[root@c7-41 ~]# mkdir /ISO
[root@c7-41 ~]# cd /ISO/
[root@c7-41 ISO]# ls
CentOS-7-x86_64-DVD-1908.iso
[root@c7-41 ISO]# virt-install --virt-type kvm --name CentOS-7-x86_64 --ram 1024 --cdrom=/ISO/CentOS-7-x86_64-DVD-1908.iso --disk path=/opt/CentOS-7-x86_64.raw --network network=default --graphics vnc,listen=0.0.0.0 --noautoconsole
Starting install...
Domain installation still in progress. You can reconnect to
the console to complete the installation process.vpn下载地址 这时候使用VNC工具,连接主机IP 10.0.0.41,设置安装操作系统的网卡名称为eth0,如图所示
使用tab
回车
安装步骤和我们平时安装操作系统的方法一样,安装完成后,可以使用virsh list --all显示KVM上所有的虚拟机
[root@c7-41 ISO]# virsh list --all
Id Name State
----------------------------------------------------
- CentOS-7-x86_64 shut off # 可以看到虚拟机的名称和状态四. 管理KVM
1. 使用virsh启动KVM中的虚拟机
[root@c7-41 ISO]# virsh start CentOS-7-x86_64
Domain CentOS-7-x86_64 started启动后,使用VNC连接工具,登录后可以看到网卡的名称为eth0,默认没有ip地址,是因为网卡没有激活,将ONBOOT改为yes,重启网卡,可以看到ip地址为192.168.122.0网段的
当KVM中的虚拟机启动后,可以在/etc/libvirt/qemu目录下,看到启动的虚拟机的信息
root@c7-41 ISO]# cd /etc/libvirt/qemu
[root@c7-41 qemu]# pwd
/etc/libvirt/qemu
[root@c7-41 qemu]# ls -lh
total 8.0K
-rw------- 1 root root 4.2K May 9 18:11 CentOS-7-x86_64.xml
drwx------ 3 root root 42 May 9 18:08 networksCentOS-7-x86_64.xml就是启动的虚拟机的信息,当我们使用vim编辑器查看时,会提示如下信息:
<!--
WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE
OVERWRITTEN AND LOST. Changes to this xml configuration should be made using:
virsh edit CentOS-7-x86_64
or other application using the libvirt API.
-->看到提示需要修改虚拟机的信息,需要使用命令 virsh edit CentOS-7-x86_64,是用这条命令后,我们可以看到很多虚拟机的信息,包括vcpu,memory等
[root@c7-41 qemu]# virsh edit CentOS-7-x86_64
<domain type='kvm'>
<name>CentOS-7-x86_64</name>
<uuid>e7c924f2-2ebf-4eca-9124-b6740b70a4fb</uuid>
<memory unit='KiB'>1048576</memory>
<currentMemory unit='KiB'>1048576</currentMemory>
<vcpu placement='auto' current='1'>4</vcpu>
<os>
<type arch='x86_64' machine='pc-i440fx-rhel7.0.0'>hvm</type>
<boot dev='hd'/>
</os>
<features>
<acpi/>
<apic/>
</features>
<cpu mode='custom' match='exact' check='partial'>
<model fallback='allow'>Broadwell-noTSX-IBRS</model>
<feature policy='require' name='md-clear'/>
<feature policy='require' name='spec-ctrl'/>
<feature policy='require' name='ssbd'/>
</cpu>
<clock offset='utc'>
<timer name='rtc' tickpolicy='catchup'/>
<timer name='pit' tickpolicy='delay'/>
<timer name='hpet' present='no'/>
</clock>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>destroy</on_crash>
<pm>
<suspend-to-mem enabled='no'/>
<suspend-to-disk enabled='no'/>
</pm>
<devices>
"/tmp/virsh1kbtgk.xml" 107L, 4024C written
Domain CentOS-7-x86_64 XML configuration edited.2. CPU热添加(
#KVM支持CPU的热添加,不过局限是宿主机和虚拟机的系统相同才行,这里宿主机是CentOS7,虚拟机也是CentOS7,所以可以模拟CPU热添加,不过真实生产环境不建议这样操作)
[root@c7-41 qemu]# virsh edit CentOS-7-x86_64
<vcpu placement='static'>1</vcpu> 修改为:
<vcpu placement='auto' current='1'>4</vcpu>
#修改成这个##意思是当前cpu为1核,最多可以有4核,修改完虚拟机的配置文件,必须关闭虚拟机再启动,配置才能生效[root@c7-41 qemu]# virsh shutdown CentOS-7-x86_64 #关闭虚拟机
Domain CentOS-7-x86_64 is being shutdown
[root@c7-41 qeum ~]# virsh list --all ##查看虚拟机状态
Id Name State
----------------------------------------------------
- CentOS-7-x86_64 shut off
[root@c7-41 qemu]# virsh start CentOS-7-x86_64 #启动虚拟机
Domain CentOS-7-x86_64 started
[root@c7-41 qemu]# virsh list --all
Id Name State
----------------------------------------------------
3 CentOS-7-x86_64 running先通过VNC工具查看虚拟机的cpu信息
在宿主机上通过命令添加核数
[root@c7-41 qemu]# virsh setvcpus CentOS-7-x86_64 2 --live
#虚拟机的cpu添加到2core再通过VNC工具查看虚拟机CPU信息
3. 内存热添加
(还是不建议生产中使用,知道功能就行了)
通过VNC连接虚拟机,查看虚拟机内存
[root@c7-41 qemu]# virsh qemu-monitor-command CentOS-7-x86_64 --hmp --cmd info balloon
balloon: actual=1024
# 查看当前虚拟机的内存
[root@c7-41 qemu]# virsh qemu-monitor-command CentOS-7-x86_64 --hmp --cmd balloon 512
# 修改当前虚拟机的内存为512
[root@c7-41 qemu]# virsh qemu-monitor-command CentOS-7-x86_64 --hmp --cmd info balloon
balloon: actual=512
# 查看修改的内存信息已经改变成了512使用VNC工具连接虚拟机,查看内存是否有变:
4. 网卡配置
(如何将KVM虚拟机中的网卡改为桥接模式,让局域网的其他用户可以正常访问)
[root@c7-41 qemu]# brctl show
bridge name bridge id STP enabled interfaces
virbr0 8000.5254003a7202 yes virbr0-nic
vnet0创建一个脚本
#创建一个脚本,删除ens33网卡的ip信息,新建一个桥接网卡,并且将ens33网卡的ip信息富裕新建的桥接网卡
[root@c7-41 qemu]# cd
[root@c7-41 ~]# cat br0.sh
#!/bin/bash
brctl addbr br0 #创建一个桥接网卡br0
brctl addif br0 ens33 #将ens33网卡的桥接信息转到br0网卡
ip addr del dev ens33 10.0.0.41/24 #将ens33网卡的ip信息删除
ifconfig br0 10.0.0.41/24 up #将ens33网卡的ip信息这只到br0网卡上
route add default gw 10.0.0.2 #添加网关
[root@c7-41 ~]# chmod u+x br0.sh
[root@c7-41 ~]# ./br0.sh
#使用ifocnfig查看网卡的ip信息,可以看到br0的地址已经变为了10.0.0.41/24
[root@c7-41 ~]# ifconfig
br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.0.0.41 netmask 255.255.255.0 broadcast 10.0.0.255
inet6 fe80::20c:29ff:fe49:48c7 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:49:48:c7 txqueuelen 1000 (Ethernet)
RX packets 42 bytes 2438 (2.3 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 63 bytes 4762 (4.6 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet6 fe80::20c:29ff:fe49:48c7 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:49:48:c7 txqueuelen 1000 (Ethernet)
RX packets 3523503 bytes 4923288560 (4.5 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 313418 bytes 52607195 (50.1 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ens37: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.16.1.41 netmask 255.255.0.0 broadcast 172.16.255.255
inet6 fe80::20c:29ff:fe49:48d1 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:49:48:d1 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 14 bytes 1016 (1016.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
virbr0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255
ether 52:54:00:75:79:e4 txqueuelen 1000 (Ethernet)
RX packets 81 bytes 6682 (6.5 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 46 bytes 5691 (5.5 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
vnet0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet6 fe80::fc54:ff:fedb:1c4c prefixlen 64 scopeid 0x20<link>
ether fe:54:00:db:1c:4c txqueuelen 1000 (Ethernet)
RX packets 19 bytes 1712 (1.6 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 147 bytes 8262 (8.0 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0使用命令修改KVM虚拟机的信息
[root@c7-41 ~]# virsh edit CentOS-7-x86_64
72 <interface type='network'> 修改为:
<interface type='bridge'>
74 <source network='default'/> 修改为:
<source bridge='br0'/>修改完成后关闭虚拟机,启动虚拟机,通过VNC工具修改ip为10.0.0.88,尝试ping宿主机是否可以ping通,并通过ssh连接
[root@c7-41 ~]# virsh shutdown CentOS-7-x86_64
Domain CentOS-7-x86_64 is being shutdown
[root@c7-41 ~]# virsh start CentOS-7-x86_64
Domain CentOS-7-x86_64 started
通过本地的Xshell软件,尝试连接,可以连接,并且可以看到IP信息
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