KVM是Kernel-based Virtual Machine的簡稱,是一個開源的虛擬化模塊,今天我將在CentOS7的操作系統上安裝KVM
一.環境信息
系統: CentOS 7.7 IP: 10.0.0.41/24
在虛擬機安裝時,需要啓用CPU的虛擬化功能
二. KVM安裝步驟
1. 安裝qemu-kvm和libvirt
#qemu-kvm用來創建虛擬機硬盤,libvirt用來管理虛擬機
[root@c7-41 ~]# yum install -y qemu-kvm libvirt
2. 安裝virt-install
#用來創建虛擬機
[root@c7-41 ~]# yum install -y virt-install
3. 啓動libvirtd,並將它設爲開機啓動,
#啓動後使用ifconfig查看,發現會多出來一塊virbr0的網卡,ip默認爲192.168.122.1/24,說明libvirtd啓動成功,如果默認沒有ifconfig命令,使用yum install -y net-tools安裝
[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
經過以上三步,KVM安裝成功,下面開始使用KVM創建虛擬機.
三. 使用KVM創建虛擬機(Centos7)
1. 使用qemu命令創建一個10G的硬盤
#最小10,G,可以更多,硬盤的名稱爲: 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.raw
2. 使用virt-install創建名稱爲CentOS-7-x86_64的虛擬機
#在創建之前,先上傳一個CentOS7的ISO鏡像,最好在根目錄下創建一個ISO的目錄文件夾
[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下載地址
這時候使用VNC工具,連接主機IP 10.0.0.41,設置安裝操作系統的網卡名稱爲eth0,如圖所示
使用tab
回車
安裝步驟和我們平時安裝操作系統的方法一樣,安裝完成後,可以使用virsh list --all顯示KVM上所有的虛擬機
[root@c7-41 ISO]# virsh list --all
Id Name State
----------------------------------------------------
- CentOS-7-x86_64 shut off # 可以看到虛擬機的名稱和狀態
四. 管理KVM
1. 使用virsh啓動KVM中的虛擬機
[root@c7-41 ISO]# virsh start CentOS-7-x86_64
Domain CentOS-7-x86_64 started
啓動後,使用VNC連接工具,登錄後可以看到網卡的名稱爲eth0,默認沒有ip地址,是因爲網卡沒有激活,將ONBOOT改爲yes,重啓網卡,可以看到ip地址爲192.168.122.0網段的
當KVM中的虛擬機啓動後,可以在/etc/libvirt/qemu目錄下,看到啓動的虛擬機的信息
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 networks
CentOS-7-x86_64.xml就是啓動的虛擬機的信息,當我們使用vim編輯器查看時,會提示如下信息:
<!--
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.
-->
看到提示需要修改虛擬機的信息,需要使用命令 virsh edit CentOS-7-x86_64,是用這條命令後,我們可以看到很多虛擬機的信息,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熱添加(
#KVM支持CPU的熱添加,不過侷限是宿主機和虛擬機的系統相同才行,這裏宿主機是CentOS7,虛擬機也是CentOS7,所以可以模擬CPU熱添加,不過真實生產環境不建議這樣操作)
[root@c7-41 qemu]# virsh edit CentOS-7-x86_64
<vcpu placement='static'>1</vcpu> 修改爲:
<vcpu placement='auto' current='1'>4</vcpu>
#修改成這個##意思是當前cpu爲1核,最多可以有4核,修改完虛擬機的配置文件,必須關閉虛擬機再啓動,配置才能生效
[root@c7-41 qemu]# virsh shutdown CentOS-7-x86_64 #關閉虛擬機
Domain CentOS-7-x86_64 is being shutdown
[root@c7-41 qeum ~]# virsh list --all ##查看虛擬機狀態
Id Name State
----------------------------------------------------
- CentOS-7-x86_64 shut off
[root@c7-41 qemu]# virsh start CentOS-7-x86_64 #啓動虛擬機
Domain CentOS-7-x86_64 started
[root@c7-41 qemu]# virsh list --all
Id Name State
----------------------------------------------------
3 CentOS-7-x86_64 running
先通過VNC工具查看虛擬機的cpu信息
在宿主機上通過命令添加核數
[root@c7-41 qemu]# virsh setvcpus CentOS-7-x86_64 2 --live
#虛擬機的cpu添加到2core
再通過VNC工具查看虛擬機CPU信息
3. 內存熱添加
(還是不建議生產中使用,知道功能就行了)
通過VNC連接虛擬機,查看虛擬機內存
[root@c7-41 qemu]# virsh qemu-monitor-command CentOS-7-x86_64 --hmp --cmd info balloon
balloon: actual=1024
# 查看當前虛擬機的內存
[root@c7-41 qemu]# virsh qemu-monitor-command CentOS-7-x86_64 --hmp --cmd balloon 512
# 修改當前虛擬機的內存爲512
[root@c7-41 qemu]# virsh qemu-monitor-command CentOS-7-x86_64 --hmp --cmd info balloon
balloon: actual=512
# 查看修改的內存信息已經改變成了512
使用VNC工具連接虛擬機,查看內存是否有變:
4. 網卡配置
(如何將KVM虛擬機中的網卡改爲橋接模式,讓局域網的其他用戶可以正常訪問)
[root@c7-41 qemu]# brctl show
bridge name bridge id STP enabled interfaces
virbr0 8000.5254003a7202 yes virbr0-nic
vnet0
創建一個腳本
#創建一個腳本,刪除ens33網卡的ip信息,新建一個橋接網卡,並且將ens33網卡的ip信息富裕新建的橋接網卡
[root@c7-41 qemu]# cd
[root@c7-41 ~]# cat br0.sh
#!/bin/bash
brctl addbr br0 #創建一個橋接網卡br0
brctl addif br0 ens33 #將ens33網卡的橋接信息轉到br0網卡
ip addr del dev ens33 10.0.0.41/24 #將ens33網卡的ip信息刪除
ifconfig br0 10.0.0.41/24 up #將ens33網卡的ip信息這隻到br0網卡上
route add default gw 10.0.0.2 #添加網關
[root@c7-41 ~]# chmod u+x br0.sh
[root@c7-41 ~]# ./br0.sh
#使用ifocnfig查看網卡的ip信息,可以看到br0的地址已經變爲了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虛擬機的信息
[root@c7-41 ~]# virsh edit CentOS-7-x86_64
72 <interface type='network'> 修改爲:
<interface type='bridge'>
74 <source network='default'/> 修改爲:
<source bridge='br0'/>
修改完成後關閉虛擬機,啓動虛擬機,通過VNC工具修改ip爲10.0.0.88,嘗試ping宿主機是否可以ping通,並通過ssh連接
[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
通過本地的Xshell軟件,嘗試連接,可以連接,並且可以看到IP信息
