KVM 是 Kernel-based Virtual Machine 的简称，是 Linux 下 x86 硬件平台上的全功能虚拟化解决方案；
使用 KVM ，可允许运行多个虚拟机，包括 Linux 和 Windows操作系统。
KVM的虚拟化需要硬件支持（如Intel VT技术或者AMD V技术)。是基于硬件的完全虚拟化。
KVM 安装
在Windows 7系统中安装使用vmware，在vmware里安装linux系统，并在linux系统中安装使用kvm，虚拟化linux系统。
VMware: VMware® Workstation 10.0.0 build-1295980
Linux: CentOS-6.8-x86_64-minimal.iso
一、在VMware中安装Linux CentOS系统
使用自定义方式安装CentOS
先创建虚拟机，然后再在光驱中指定iso镜像文件，再安装linux系统。
系统安装完成后，关闭操作系统，打开CentOS系统的虚拟机设置，点击处理器，选择“虚拟化..."
重启系统
命令检查是否支持虚拟化，
egrep -c '(vmx|svm)' /proc/cpuinfo
结果为支持虚拟化的核数
二、设置网络
修改ip地址为静态ip
vi /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
TYPE=Ethernet
ONBOOT=yes
NM_CONTROLLED=yes
BOOTPROTO=static
IPADDR=192.168.126.200
NETMASK=255.255.255.0
GATEWAY=192.168.126.2
CentOS的网络链接方式是NAT模式，子网IP是192.168.126.0，设置IP地址为192.168.126.200
GATEWAY的设置为虚拟网络编辑器中的NAT设置中的网关地址
重启网络
service network
或重启主机
init 6
检查是否能够访问外网
ping www.baidu.com
三、通过yum安装KVM
安装kvm
yum -y install qemu-kvm
安装管理工具
yum -y install virt-manager libvirt libvirt-python python-virtinst bridge-utils
libvirt 是一套免费、开源的支持Linux下主流虚拟化工具的C函数库。提供一套方便、可靠的编程接口，支持与C,C++,Ruby,Python,Java等多种主流开发语言的绑定。
它支持各种虚拟机监控程序，包括 Xen 和 KVM，以及 QEMU 和用于其他操作系统的一些虚拟产品。
启动，并设置开机启动项
service libvirtd start
chkconfig libvirt don
如果不能安装或安装慢，可以换阿里开源镜像
http://mirrors.aliyun.com/
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo
内核模块查看
查看已载入系统的模块
lsmod | grep kvm
[root@kvm ~]# lsmod| grep kvm
kvm_intel 55464 0
kvm 345038 1 kvm_intel
载入模块
modprobe kvm
modprobe kvm-intel
四、创建虚拟系统
关闭防火墙
service iptables stop
关闭防火墙启动项
chkconfig iptables off
创建磁盘镜像文件
qemu-img 磁盘镜像工具
qemu-img --help 查看帮助
create [-f fmt] [-o options] filename [size]
fmt磁盘镜像文件格式，支持的格式有：raw cow qcow vdi vmdk cloop dmg bochs vpc vvfat qcow2 qed vhdx parallels nbd blkdebug null host_cdrom host_floppy host_device file gluster
执行脚本：
[root@kvm ~]# mkdir /kvmImg
[root@kvm ~]# qemu-img create -f qcow2 /kvmImg/centos-6.8.qcow2 5G
Formatting '/kvmImg/centos-6.8.qcow2', fmt=qcow2 size= encryption=off cluster_size=
安装虚拟机
虚拟机安装的系统为：CentOS-6.8-x86_64-minimal.iso
先将镜像文件上传至主机的/kvmImg目录下
virt-install 工具
virt-install --help 查看帮助
脚本命令：
virt-install --virt-type kvm --name centos-6.8 --ram \
--vcpus \
--cdrom=/kvmImg/CentOS-6.8-x86_64-minimal.iso \
--disk /kvmImg/centos-6.8.qcow2,format=qcow2 \
--network network=default \
--graphics vnc,listen=0.0.0.0 --noautoconsole \
--os-type=linux --os-variant=rhel6
[root@kvm kvmImg]# virt-install --virt-type kvm --name centos-6.8 --ram \
> --vcpus \
> --cdrom=/kvmImg/CentOS-6.8-x86_64-minimal.iso \
> --disk /kvmImg/centos-6.8.qcow2,format=qcow2 \
> --network network=default \
> --graphics vnc,listen=0.0.0.0 --noautoconsole \
> --os-type=linux --os-variant=rhel6 Starting install...
Creating domain... | B :
Domain installation still in progress. You can reconnect to
the console to complete the installation process.
由于在创建脚本中指定了来宾的图形化工具为VNC --graphics vnc,listen=0.0.0.0，然后通过VNC进入虚拟机，在创建时可指定端口(参考帮助)，由于没有指定端口，需要查询一下端口号。
查看qemu-kvm虚拟机的端口号为 5900
[root@kvm kvmImg]# netstat -antp|grep kvm
tcp 0.0.0.0: 0.0.0.0:* LISTEN /qemu-kvm
通过VNC进入虚拟机
点击ok,进入系统
然后就可以通过vnc对系统进行安装设置，安装完成后，需要重启虚拟机，点击重启
虚拟机没了，找找虚拟机哪里去了
查看端口查找不到
[root@kvm kvmImg]# netstat -antp|grep kvm
那虚拟机应该是关闭了，怎么查看虚拟机的状态，怎么把它启动起来哪？
接下来需要用到virsh工具
Virsh：基于libvirt的命令行工具（CLI）
[root@kvm ~]# virsh
Welcome to virsh, the virtualization interactive terminal. Type: 'help' for help with commands
'quit' to quit
virsh的帮助
virsh # help
Grouped commands: Domain Management (help keyword 'domain'):
attach-device attach device from an XML file
attach-disk attach disk device
attach-interface attach network interface
autostart autostart a domain
blkdeviotune Set or query a block device I/O tuning parameters.
blkiotune Get or set blkio parameters
blockcommit Start a block commit operation.
blockcopy Start a block copy operation.
blockjob Manage active block operations
blockpull Populate a disk from its backing image.
blockresize Resize block device of domain.
change-media Change media of CD or floppy drive
console connect to the guest console
cpu-baseline compute baseline CPU
cpu-compare compare host CPU with a CPU described by an XML file
cpu-stats show domain cpu statistics
create create a domain from an XML file
define define (but don't start) a domain from an XML file
desc show or set domain's description or title
destroy destroy (stop) a domain
detach-device detach device from an XML file
detach-disk detach disk device
detach-interface detach network interface
domdisplay domain display connection URI
domhostname print the domain's hostname
domid convert a domain name or UUID to domain id
domif-setlink set link state of a virtual interface
domiftune get/set parameters of a virtual interface
domjobabort abort active domain job
domjobinfo domain job information
domname convert a domain id or UUID to domain name
dompmsuspend suspend a domain gracefully using power management functions
dompmwakeup wakeup a domain from pmsuspended state
domuuid convert a domain name or id to domain UUID
domxml-from-native Convert native config to domain XML
domxml-to-native Convert domain XML to native config
dump dump the core of a domain to a file for analysis
dumpxml domain information in XML
edit edit XML configuration for a domain
inject-nmi Inject NMI to the guest
send-key Send keycodes to the guest
managedsave managed save of a domain state
managedsave-remove Remove managed save of a domain
maxvcpus connection vcpu maximum
memtune Get or set memory parameters
migrate migrate domain to another host
migrate-setmaxdowntime set maximum tolerable downtime
migrate-setspeed Set the maximum migration bandwidth
migrate-getspeed Get the maximum migration bandwidth
numatune Get or set numa parameters
reboot reboot a domain
reset reset a domain
restore restore a domain from a saved state in a file
resume resume a domain
save save a domain state to a file
save-image-define redefine the XML for a domain's saved state file
save-image-dumpxml saved state domain information in XML
save-image-edit edit XML for a domain's saved state file
schedinfo show/set scheduler parameters
screenshot take a screenshot of a current domain console and store it into a file
setmaxmem change maximum memory limit
setmem change memory allocation
setvcpus change number of virtual CPUs
shutdown gracefully shutdown a domain
start start a (previously defined) inactive domain
suspend suspend a domain
ttyconsole tty console
undefine undefine a domain
update-device update device from an XML file
vcpucount domain vcpu counts
vcpuinfo detailed domain vcpu information
vcpupin control or query domain vcpu affinity
emulatorpin control or query domain emulator affinity
vncdisplay vnc display Domain Monitoring (help keyword 'monitor'):
domblkerror Show errors on block devices
domblkinfo domain block device size information
domblklist list all domain blocks
domblkstat get device block stats for a domain
domcontrol domain control interface state
domif-getlink get link state of a virtual interface
domiflist list all domain virtual interfaces
domifstat get network interface stats for a domain
dominfo domain information
dommemstat get memory statistics for a domain
domstate domain state
list list domains Host and Hypervisor (help keyword 'host'):
capabilities capabilities
freecell NUMA free memory
hostname print the hypervisor hostname
node-memory-tune Get or set node memory parameters
nodecpustats Prints cpu stats of the node.
nodeinfo node information
nodememstats Prints memory stats of the node.
nodesuspend suspend the host node for a given time duration
qemu-attach QEMU Attach
qemu-monitor-command QEMU Monitor Command
qemu-agent-command QEMU Guest Agent Command
sysinfo print the hypervisor sysinfo
uri print the hypervisor canonical URI
version show version Interface (help keyword 'interface'):
iface-begin create a snapshot of current interfaces settings, which can be later committed (iface-commit) or restored (iface-rollback)
iface-bridge create a bridge device and attach an existing network device to it
iface-commit commit changes made since iface-begin and free restore point
iface-define define (but don't start) a physical host interface from an XML file
iface-destroy destroy a physical host interface (disable it / "if-down")
iface-dumpxml interface information in XML
iface-edit edit XML configuration for a physical host interface
iface-list list physical host interfaces
iface-mac convert an interface name to interface MAC address
iface-name convert an interface MAC address to interface name
iface-rollback rollback to previous saved configuration created via iface-begin
iface-start start a physical host interface (enable it / "if-up")
iface-unbridge undefine a bridge device after detaching its slave device
iface-undefine undefine a physical host interface (remove it from configuration) Network Filter (help keyword 'filter'):
nwfilter-define define or update a network filter from an XML file
nwfilter-dumpxml network filter information in XML
nwfilter-edit edit XML configuration for a network filter
nwfilter-list list network filters
nwfilter-undefine undefine a network filter Networking (help keyword 'network'):
net-autostart autostart a network
net-create create a network from an XML file
net-define define (but don't start) a network from an XML file
net-destroy destroy (stop) a network
net-dumpxml network information in XML
net-edit edit XML configuration for a network
net-info network information
net-list list networks
net-name convert a network UUID to network name
net-start start a (previously defined) inactive network
net-undefine undefine an inactive network
net-update update parts of an existing network's configuration
net-uuid convert a network name to network UUID Node Device (help keyword 'nodedev'):
nodedev-create create a device defined by an XML file on the node
nodedev-destroy destroy (stop) a device on the node
nodedev-detach detach node device from its device driver
nodedev-dumpxml node device details in XML
nodedev-list enumerate devices on this host
nodedev-reattach reattach node device to its device driver
nodedev-reset reset node device Secret (help keyword 'secret'):
secret-define define or modify a secret from an XML file
secret-dumpxml secret attributes in XML
secret-get-value Output a secret value
secret-list list secrets
secret-set-value set a secret value
secret-undefine undefine a secret Snapshot (help keyword 'snapshot'):
snapshot-create Create a snapshot from XML
snapshot-create-as Create a snapshot from a set of args
snapshot-current Get or set the current snapshot
snapshot-delete Delete a domain snapshot
snapshot-dumpxml Dump XML for a domain snapshot
snapshot-edit edit XML for a snapshot
snapshot-info snapshot information
snapshot-list List snapshots for a domain
snapshot-parent Get the name of the parent of a snapshot
snapshot-revert Revert a domain to a snapshot Storage Pool (help keyword 'pool'):
find-storage-pool-sources-as find potential storage pool sources
find-storage-pool-sources discover potential storage pool sources
pool-autostart autostart a pool
pool-build build a pool
pool-create-as create a pool from a set of args
pool-create create a pool from an XML file
pool-define-as define a pool from a set of args
pool-define define (but don't start) a pool from an XML file
pool-delete delete a pool
pool-destroy destroy (stop) a pool
pool-dumpxml pool information in XML
pool-edit edit XML configuration for a storage pool
pool-info storage pool information
pool-list list pools
pool-name convert a pool UUID to pool name
pool-refresh refresh a pool
pool-start start a (previously defined) inactive pool
pool-undefine undefine an inactive pool
pool-uuid convert a pool name to pool UUID Storage Volume (help keyword 'volume'):
vol-clone clone a volume.
vol-create-as create a volume from a set of args
vol-create create a vol from an XML file
vol-create-from create a vol, using another volume as input
vol-delete delete a vol
vol-download download volume contents to a file
vol-dumpxml vol information in XML
vol-info storage vol information
vol-key returns the volume key for a given volume name or path
vol-list list vols
vol-name returns the volume name for a given volume key or path
vol-path returns the volume path for a given volume name or key
vol-pool returns the storage pool for a given volume key or path
vol-resize resize a vol
vol-upload upload file contents to a volume
vol-wipe wipe a vol Virsh itself (help keyword 'virsh'):
cd change the current directory
connect (re)connect to hypervisor
echo echo arguments
exit quit this interactive terminal
help print help
pwd print the current directory
quit quit this interactive terminal
查看帮助，使用list命令
virsh # list
Id Name State
---------------------------------------------------- virsh # list --all
Id Name State
----------------------------------------------------
- centos-6.8 shut off
使用 list --al列出所有，查看centos-6.8状态是shut off，那接下里想办法把他启动起来
查看帮助，使用start命令
virsh # start centos-6.8
Domain centos-6.8 started
start命令后面参数是虚拟机名称，提示已经启动起来，然后通过vnc链接测试，可以登录系统，一个虚拟机完成简单安装。