宿主機CentOS Linux release 7.2.1511 (Core)，內核3.10.0-327.el7.x86_64
1、配置宿主機網絡橋接
想讓虛擬機有自己的ip且外網可訪問，需要在安裝虛擬機前配置宿主機網絡（橋接BRIDGE）：
在目錄/etc/sysconfig/network-scripts下，將原始的ifcfg-enp2s0重命名ifcfg-enp2s0.old當備份，然后新建ifcfg-enp2s0內容如下：
TYPE=Ethernet
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=none
DEFROUTE=yes
NAME=enp2s0
DEVICE=enp2s0
ONBOOT=yes
BRIDGE=br0
NM_CONTROLLED=no
再新建ifcgf-br0內容如下：
TYPE=Bridge
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=static
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=br0
DEVICE=br0
NM_CONTROLLED=no
ONBOOT=yes
IPADDR=223.129.0.xxx
PREFIX=25
GATEWAY=223.129.0.xxx
DNS1=8.8.8.8
IPV6_PRIVACY=no
ZONE=public
重啟網絡：systemctl restart network
有時候會報錯：
Restarting network (via systemctl): Job for network.service failed because the control process exited with error code. See "systemctl status network.service" and "journalctl -xe" for details.
可以通過journalctl -xe查看具體原因，我這里和該文http://blog.51cto.com/addam/1839518問題類似，所以通過：systemctl stop NetworkManager，然后再重啟網絡解決了...
ifconfig看到如下信息（要是不對可以嘗試重啟機器...）
br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 223.129.0.xxx netmask 255.255.255.xxx broadcast 223.129.0.xxx inet6 fe80::4a5b:39ff:fea4:3ef0 prefixlen 64 scopeid 0x20<link> ether 48:5b:39:a4:3e:f0 txqueuelen 0 (Ethernet) RX packets 4016129 bytes 379659216 (362.0 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 7392459 bytes 11078132347 (10.3 GiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 enp2s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet6 fe80::4a5b:39ff:fea4:3ef0 prefixlen 64 scopeid 0x20<link> ether 48:5b:39:a4:3e:f0 txqueuelen 1000 (Ethernet) RX packets 4260879 bytes 791804516 (755.1 MiB) RX errors 0 dropped 1092 overruns 0 frame 0 TX packets 7528373 bytes 11088764715 (10.3 GiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
2、命令行安裝kvm虛擬機
安裝必要的軟件這里就不說了...
ubuntu下（前兩條用於安裝，第三條用於啟動）：
1 qemu-img create -f qcow2 /home/kvm/centos7-1511.img 20G
2 qemu-system-x86_64 -m 2048 -enable-kvm -hda /home/kvm/centos7-1511.img -cdrom /home/isos/CentOS-7-x86_64-DVD-1511.iso -boot d
3 qemu-system-x86_64 -enable-kvm -m 1024 -boot menu=on /home/kvm/centos7-1511.img
centos下：
1 qemu-img create -f qcow2 /home/kvm/centos7-1511.img 20G
2 /usr/libexec/qemu-kvm -m 2048 -enable-kvm -hda /home/kvm/centos7-1708.img -cdrom /home/isos/CentOS-7-x86_64-DVD-1511.iso -boot d
3 /usr/libexec/qemu-kvm -enable-kvm -m 1024 -boot menu=on /home/kvm/centos7-1511.img
如果用ubuntu下的命令2在centos下運行，會出現問題：
1、bash: qemu-system-x86_64: 未找到命令...
解決：qemu-system-x86_64是在安裝qemu（注意不是qemu-kvm）時生成的命令，而centos下默認安裝的是qemu-kvm包，對應的命令是qemu-kvm。通過rpm -ql qemu-kvm查看輸出：/usr/libexec/qemu-kvm，用此替換得到centos下正確的命令2。
正確命令2運行后，輸出信息是：
2、VNC server running on `::1:5900'
解決：在xshell下運行：vncviewer :5900，會出現
....
Can't open display:
所以用vncviewer連接到目標主機，然后在圖形界面下運行vncviewer :5900，即會跳出安裝centos的界面，順着安裝即可（記得在SOFTWARE SELECTION選擇要最小安裝還是圖形界面）
3、讓virt-manager可以管理剛才新建的虛擬機
運行完上述的命令1和2后，如果不想每次都通過命令3啟動虛擬機，可以通過libvirt管理（這樣以后直接virsh start 虛擬機名，即可開啟虛擬機）
libvirt（包括virsh）使用xml文件對虛擬機進行配置，其中包括虛擬機名稱、分配內存、vcpu等多種信息
下面是一個名為centos7-1511.xml的xml文件，其中定義了一個名為centos7-1511的kvm虛擬機（如果是32位要寫i686）
<domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
<name>centos7-1511</name>
<uuid>af939aef-c0eb-4b83-96ca-c23aecd3e057</uuid>
<memory unit='KiB'>1048576</memory>
<currentMemory unit='KiB'>1048576</currentMemory>
<vcpu placement='static'>1</vcpu>
<os>
<type arch='x86_64' machine='pc-i440fx-rhel7.0.0'>hvm</type>
<boot dev='hd'/>
<bootmenu enable='yes'/>
<bios useserial='yes' rebootTimeout='0'/>
</os>
<features>
<acpi/>
<apic/>
</features>
<cpu mode='custom'>
<model fallback='allow'></model>
</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>restart</on_crash>
<pm>
<suspend-to-mem enabled='no'/>
<suspend-to-disk enabled='no'/>
</pm>
<devices>
<emulator>/usr/libexec/qemu-kvm</emulator>
<disk type='file' device='disk'>
<driver name='qemu' type='qcow2'/>
<source file='/home/kvm/centos7-1511.img'/>
<target dev='vda' bus='virtio'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
</disk>
<disk type='block' device='cdrom'>
<driver name='qemu' type='raw'/>
<target dev='hda' bus='ide'/>
<readonly/>
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
</disk>
<controller type='usb' index='0'>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
</controller>
<controller type='pci' index='0' model='pci-root'/>
<controller type='ide' index='0'>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
</controller>
<interface type='network'>
<mac address='48:5b:39:a4:3e:f1'/>
<source network='default'/>
<model type='e1000'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
</interface>
<serial type='pty'>
<target port='0'/>
</serial>
<console type='pty'>
<target type='serial' port='0'/>
</console>
<input type='tablet' bus='usb'/>
<input type='mouse' bus='ps2'/>
<input type='keyboard' bus='ps2'/>
<graphics type='vnc' port='-1' autoport='yes' listen='0.0.0.0'>
<listen type='address' address='0.0.0.0'/>
</graphics>
<video>
<model type='cirrus' vram='16384' heads='1'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
</video>
<memballoon model='virtio'>
<address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
</memballoon>
</devices>
</domain>
然后運行下面的命令即可通過virt-manager管理名為centos7-1511的kvm虛擬機
1 [root@localhost kvm]# virsh define centos7-1511.xml 定義域 centos7-1511（從 centos7-1511.xml） 2 [root@localhost kvm]# virsh list --all Id 名稱 狀態 ---------------------------------------------------- - centos7-1511 關閉 3 [root@localhost kvm]# virsh start centos7-1511 域 centos7-1511 已開始
命令3可能會有問題：
[root@localhost kvm]# virsh start centos7-1511
錯誤：開始域 centos7-1511 失敗
錯誤：internal error: process exited while connecting to monitor: qemu-kvm: -machine pc-i440fx-2.0,accel=kvm,usb=off,dump-guest-core=off: Unsupported machine type
Use -machine help to list supported machines!
通過以下命令：
[root@localhost kvm]# /usr/libexec/qemu-kvm -machine help
Supported machines are:
none empty machine
pc RHEL 7.0.0 PC (i440FX + PIIX, 1996) (alias of pc-i440fx-rhel7.0.0)
pc-i440fx-rhel7.0.0 RHEL 7.0.0 PC (i440FX + PIIX, 1996) (default)
rhel6.6.0 RHEL 6.6.0 PC
rhel6.5.0 RHEL 6.5.0 PC
rhel6.4.0 RHEL 6.4.0 PC
rhel6.3.0 RHEL 6.3.0 PC
rhel6.2.0 RHEL 6.2.0 PC
rhel6.1.0 RHEL 6.1.0 PC
rhel6.0.0 RHEL 6.0.0 PC
將xml文件中machine部分替換，然后通過下面的undefine命令取消剛才的虛擬機，再重新運行上面的define即可
可通過:
virsh undefine centos7-1511取消定義虛擬機，之后系統無法識別centos7-1511（此步驟與virsh define centos7-1511.xml對應）
virsh destroy centos7-1511直接銷毀虛擬機，取消定義，之后無法執行undefine
注意：用virt-manager第一次啟動虛擬機時別忘了修改為橋接，否則即使你在虛擬機里配置了ip等信息，ping網關啥的都會出現：Destination Host Unreachable
4、虛擬機網絡配置
修改網絡配置文件：
1、ubuntu虛擬機中修改網絡配置文件（因為有時候圖形界面操作時，會出現無法save的情況）
修改/etc/network/interfaces文件為：
# eth0是你虛擬機的網卡，可以通過ifconfig查看 auto eth0 iface eth0 inet static #ip address 223.129.0.xxx # 子網和網關 netmask 255.255.255.xxx gateway 223.129.0.xxx
修改/etc/resolvconf/resolv.conf.d/base文件，設置dns
nameserver 8.8.8.8
重啟虛擬機，通過ifconfig看到信息：
eth0 Link encap:Ethernet HWaddr 52:54:00:7c:da:c9 inet addr:223.129.0.xxx Bcast:223.129.0.xxx Mask:255.255.255.xxx inet6 addr: fe80::5054:ff:fe7c:dac9/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:219111 errors:0 dropped:0 overruns:0 frame:0 TX packets:9266 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:31389489 (31.3 MB) TX bytes:761327 (761.3 KB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:64 errors:0 dropped:0 overruns:0 frame:0 TX packets:64 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1 RX bytes:5632 (5.6 KB) TX bytes:5632 (5.6 KB)
此時用xshell連接，會出現connection failed
因為ubuntu虛擬機中必須安裝openssh-server軟件，這樣才可以通過ssh連接
安裝命令：
1 sudo apt-get install openssh-server 2 sudo /etc/init.d/ssh restart //重啟ssh服務
安裝好后，用以下命令查看22端口是否處於LISTEN狀態，如果是，則說明已經配置好了ubuntu的ssh服務
root@jin:/home/jin# netstat -ntlp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 2645/sshd
2、centos下
這個沒試，下面是通過圖形界面配置后，相應文件內容
[root@localhost network-scripts]# pwd
/etc/sysconfig/network-scripts
[root@localhost network-scripts]# cat ifcfg-ens3
TYPE="Ethernet"
BOOTPROTO="none"
DEFROUTE="yes"
IPV4_FAILURE_FATAL="no"
IPV6INIT="yes"
IPV6_AUTOCONF="yes"
IPV6_DEFROUTE="yes"
IPV6_FAILURE_FATAL="no"
NAME="ens3"
UUID="3b886635-d2a9-4569-9763-7468890a64d8"
DEVICE="ens3"
ONBOOT="yes"
DNS1="8.8.8.8"
IPADDR=223.129.0.xxx
PREFIX=25
GATEWAY=223.129.0.xxx
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes
IPV6_PRIVACY=no
補充
1、橋接和NAT
。。。。
2、創建虛擬機時各命令含義
。。。。占坑之后寫
3、libvirt
。。。