KVM虚拟化的特性
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嵌入到linux正式kernel(提高了兼容性)
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代码级资源调用(提高性能)
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虚拟机就是一个进程(内存易于管理)
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直接支持NUMA技术(提高扩展性)
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虽然被RedHat收购了,但是依然保持开源发展模式,社区活跃
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更好的商业支持及服务保障
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CentOS7较CentOS6默认支持cpu热添加,内存热添加,大页内存默认都是开启的。
支持虚拟化的条件
Inter的cpu简称为:VMX
AMD的cpu简称为:SVM
VMware需要开启如下两个条件即可,如果是物理机,需要在bios里面设置,默认都是开启的。
通过下面的命令查看虚拟化信息:
grep -E "svm|vmx" /proc/cpuinfo
flags : fpu vme de pse tsc msr pae mce cx8apic sep mtrr pge mca cmov pat pse36 clflush dts mmx fxsr sse sse2 ss syscallnx rdtscp lm constant_tsc arch_perfmon pebs bts nopl xtopology tsc_reliablenonstop_tsc aperfmperf eagerfpu pni pclmulqdq vmxssse3 cx16 pcid sse4_1 sse4_2 x2apic popcnt aes xsave avx f16c rdrandhypervisor lahf_lm ida arat epb pln pts dtherm tpr_shadow vnmi ept vpidfsgsbase smep xsaveopt flags : fpu vme de pse tsc msr pae mce cx8apic sep mtrr pge mca cmov pat pse36 clflush dts mmx fxsr sse sse2 ss htsyscall nx rdtscp lm constant_tsc arch_perfmon pebs bts nopl xtopologytsc_reliable nonstop_tsc aperfmperf pni pclmulqdq vmxssse3 cx16 pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer xsave a* vxhypervisor lahf_lm arat epb pln pts dtherm tpr_shadow vnmi ept vpid tsc_adjust
KVM的安装实战
安装管理工具和virt命令
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yum
install
-y qemu-kvm libvirt virt-
install
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Kvm:linux内核的一个模块,模块不需要安装,只需要加载
Qemu:虚拟化软件,可以虚拟不同的cpu,支持异构(x86架构可虚拟化出不是x86的架构)
Qemu-kvm:用户态管理kvm,网卡,声卡,PCI设备等都是qemu来管理的
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创建虚拟磁盘
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qemu-img create -f raw
/opt/Centos7_x86_64
.raw 10G
Formatting
'/opt/Centos7_x86_64.raw'
,
fmt
=raw size=10737418240
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创建qcow2格式的虚拟磁盘
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qemu-img create -f qcow2
/opt/Centos7_x86_64
.qcow2 10G
Formatting
'/opt/Centos7_x86_64.qcow2'
,
fmt
=qcow2 size=10737418240 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
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转换虚拟磁盘格式:
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qemu-img convert -c -f raw -O qcow2CentOS-7-x86_64.raw CentOS-7-x86_64.qcow2
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qcow2和raw的区别:
1.raw 创建多大占用多大磁盘空间
2.qcow2 占用磁盘大小根据使用量来决定 ->
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[root@linux-node1 ~]
# qemu-img info /opt/Centos7_x86_64.raw
image:
/opt/Centos7_x86_64
.raw
file
format
: raw
virtual size: 10G (10737418240 bytes)
disk size: 0
[root@linux-node1 ~]
# qemu-img info /opt/Centos7_x86_64.qcow2
image:
/opt/Centos7_x86_64
.qcow2
file
format
: qcow2
virtual size: 10G (10737418240 bytes)
disk size: 196K
cluster_size: 65536
Format specific information:
compat: 1.1
lazy refcounts:
false
refcount bits: 16
corrupt:
false
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显示内核中kvm的状态:
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[root@linux-node1 ~]
# lsmod |grep kvm
kvm_intel 162153 0
kvm 525259 1 kvm_intel
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启动管理工具服务:
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[root@linux-node1 ~]
# systemctl enable libvirtd
[root@linux-node1 ~]
# systemctl start libvirtd
[root@linux-node1 ~]
# systemctl status libvirtd
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上传镜像到node1机器中
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[root@linux-node1~]
# cd /opt/
[root@linux-node1opt]
#
wget http:
//mirrors
.aliyun.com
/centos/7
.2.1511
/isos/x86_64/CentOS-7-x86_64-DVD-1511
.iso
法二:
利用CRT的SFTP上传
CRT==> File ==> Connect SFTP Session (英文版CRT)
CRT==> 文件 ==> 连接到SFTP (中文版CRT)
sftp
>
cd
/opt
sftp
>put D:
/ISO/CentOS-7-x86_64-DVD-1511
.iso
# 将镜像上传到/opt下
法三:
[root@linux-node1~]
# cd /opt/
[root@linux-node1opt]
# dd if=/dev/cdrom of=/opt/CentOS-7.1-x86_64.iso
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创建虚拟机:
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virt-
install
--virt-
type
kvm --name Centos7.2_mini_x64 --
ram
1024 --cdrom=
/tmp/CentOS-7-x86_64-Minimal-1611
.iso --disk path=
/opt/Centos7_x86_64
.qcow2 --network network=default --graphics vnc,listen=0.0.0.0 --noautoconsole
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创建完毕的检查命令:
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[root@linux-node1 tmp]
# virsh list --all
Id Name State
----------------------------------------------------
1 Centos7.2_mini_x64 running
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虚拟机基本操作
生成kvm虚拟机:virt-install
查看再运行的虚拟机:virsh list
查看kvm虚拟机配置文件:virsh dumpxml name
启动kvm虚拟机:virsh start name
正常关机:virsh shutdown name
非正常关机:virsh destroy name
删除:virsh undefine name (彻底删除,无法找回,除非备份xml文件)
根据配置文件定义虚拟机:virsh define file-name.xml
挂起,终止:virsh suspend name
回复挂起状态:virsh resumed name
热添加CPU
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[root@linux-node1opt]
# cd /etc/libvirt/qemu/ <- 虚拟机xml路径 ->
[root@linux-node1qemu]
# ll
total4
-rw-------1 root root 3887 Dec 11 11:19 CentOS-7-x86_64.xml <-虚拟机xml文件->
注:修改虚拟机xml文件不直接修改上文所述文件,要在用virsh管理命令修改
virsh
# edit CentOS-7-x86_64 <- 控制台内修改 ->
[root@linux-node1qemu]
# virsh edit CentOS-7-x86_64 <- 控制台外修改 ->
注:热添加的CPU数不能超过最大值
[root@linux-node1qemu]
# virsh edit CentOS-7-x86_64 <- 编辑配置文件 ->
<vcpuplacement=
'static'
>1<
/vcpu
> <- 修改此行内容 ->
<vcpu placement=
'auto'
current=
"1"
>4<
/vcpu
> <- 当前为1 自动扩容 最大为4 ->
[root@linux-node1~]
# virsh shutdown CentOS-7-x86_64 <- 关闭虚拟机 ->
DomainCentOS-7-x86_64 is being
shutdown
[root@linux-node1~]
# virsh start CentOS-7-x86_64 <- 开启虚拟机 ->
DomainCentOS-7-x86_64 started
没有热添加cpu之前先查看cpu的个数
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virsh setvcpusCentOS-7-x86_64 2 --live
<-
热添加CPU ->
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添加完cpu后,查看cpu个数:
l 激活cpu
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[root@linux-node1~]
# echo "1" > /sys/devices/system/cpu/cpu1/online
高版本的kvm不需要这样做,直接可以激活
[root@linux-node1~]
# cat /sys/devices/system/cpu/cpu0/online
1
[root@linux-node1~]
# cat /sys/devices/system/cpu/cpu1/online
1
第二种添加cpu的方法:安装时指定
[root@linux-node1~]
# virt-install –vcpus 5 –vcpus 5,maxcpus=10,cpuset=1-4,6,8 –vcpussockets=2,cores=4,thread=2
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更改kvm内存配置
内存的设置拥有一个“气球(balloon)机制”,可以增大减少,但是也要设置一个最大值,默认并没有设置最大值,也可以在安装的时候指定
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[root@linux-node1~]
# virsh edit CentOS-7-x86_64 <- 编辑配置文件 ->
<memoryunit=
'KiB'
>4194304<
/memory
> <- 最大内存:4G ->
<currentMemoryunit=
'KiB'
>1048576<
/currentMemory
> <- 当前内存:1G ->
[root@linux-node1~]
# virsh qemu-monitor-command CentOS-7-x86_64 --hmp --cmd info balloon <- 查看当前内存 ->
[root@linux-node1~]
# virsh qemu-monitor-command CentOS-7-x86_64 --hmp --cmd balloon 512 <- 修改内存:512 ->
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4.8 更改虚拟机网桥连接设置
默认情况下是NAT,但是在生产环境,使用的更多的是桥接模式,更改虚拟机为网桥模式
网桥的基本原理就是创建一个桥接接口br0,在屋里网卡和虚拟网络接口之间传递数据。
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[root@linux-node1~]
# brctl addbr br0 <- 添加网桥br0 ->
[root@linux-node1~]
# brctl addif br0 eth0 <- 桥接br0和eth0 ->
注:此时会断网如果是远程操作服务器不在身边,建议写成脚本来执行
[root@linux-node1 ~]
# ip addr del dev eth0192.168.56.11/24 <- 删除eth0的IP ->
[root@linux-node1 ~]
# ifconfig br0192.168.56.11/24 up <- 给br0设置IP ->
[root@linux-node1 ~]
# route add default gw192.168.56.2 <- 给br0设置网关 ->
为了避免断网,直接写成脚本即可:
#!/bin/bash
brctl addbr br0
brctl addif br0 eth0
ip addr del dev eth0192.168.56.11
/24
ifconfig
br0192.168.56.11
/24
up
route add default gw192.168.56.2
[root@linux-node1 ~]
#virsh edit CentOS-7-x86_64 <- 修改虚拟机配置 ->
将:
<interfacetype=
'network'
<- 虚拟机网络连接方式->
<mac address=
'52:54:00:0b:f8:a5'
/>
<
source
network=
'default'
/> <- 当前主机网络名称 ->
修改为:
<interfacetype=
'bridge'
>
<mac address=
'52:54:00:0b:f8:a5'
/>
<
source
bridge=
'br0'
/>
[root@linux-node1 ~]
#virsh shutdown CentOS-7-x86_64 <- 关闭虚拟机 ->
Domain CentOS-7-x86_64 isbeing
shutdown
[root@linux-node1 ~]
#virsh start CentOS-7-x86_64 <- 启动虚拟机 ->
Domain CentOS-7-x86_64started
[root@linux-node1~]
# ifconfig <- 查看网卡信息 ->
br0:flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.56.11 netmask 255.255.255.0 broadcast 192.168.56.255
inet6 fe80::20c:29ff:fefe:1620 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:fe:16:20 txqueuelen 0 (Ethernet)
RX packets 74 bytes 8909 (8.7 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 63 bytes 11462 (11.1 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
eth0:flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet6 fe80::20c:29ff:fefe:1620 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:fe:16:20 txqueuelen 1000 (Ethernet)
RX packets 26401 bytes 26066467 (24.8 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 8582 bytes 1939240 (1.8 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo:flags=73<UP,LOOPBACK,RUNNING> mtu65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 0 (Local Loopback)
RX packets 4 bytes 216 (216.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 4 bytes 216 (216.0 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 00:00:00:00:00:00 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 2 bytes 84 (84.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
vnet0:flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
ether fe:54:00:0b:f8:a5 txqueuelen 500 (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
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本文转自 kesungang 51CTO博客,原文链接:http://blog.51cto.com/sgk2011/1886277,如需转载请自行联系原作者