四、建立虚拟机
准备工作
这里我们安装虚拟机采用NFS的方式，如果你对你的网络比较自信，也可以采用网络安装的方式，视具体情况而定。
创建一个NFS Server并将光盘根目录下的文件copy 进去，同时分享出来并允许Xen宿主机访问，这个不是重点，就不写过程了
下面进入真正的虚拟机安装阶段
# virt-install -n CentOS -r 512 --vcpus=1 \ > --nographic -f /opt/vm/centos.img -s 20 -p \ > -l nfs:192.168.1.249:/home/netinstall解释一下各参数的意义：
-n 代表虚拟机的名字 -r 分配给虚拟机的内存 --vcpus 分配给虚拟机的CPU --nographic 不适用图形界面 -f 虚拟机磁盘映像的所在地 -s 虚拟机磁盘映像的大小，单位记得是GB -p 半虚拟化的方式 -l 安装映像的路径PS：上面是采用NFS的方式，如果internet比较快，就换成internet上的源，门户网站sohu,163均有开源的镜像站点，另外中国科技大学的镜像站点也不错
# 开源镜像站点 163 sohu 科大运行上面的安装虚拟机命令后，会提示以下的信息
Starting install... Retrieving file vmlinuz... | 2.1 MB 00:00 Retrieving file initrd.img... 85% [=========================== ] 5.6 MB/s | 6.7 MB 00:00 ETA Message from syslogd@ at Fri Jun 10 15:07:07 2011 ... Xen kernel: Disabling IRQ #16 Retrieving file initrd.img... | 7.9 MB 00:00 Creating storage file... | 20 GB 00:00 Creating domain... | 0 B 00:00 Connected to domain centos Escape character is ^] Bootdata ok (command line is method=nfs:192.168.1.249:/home/netinstall) Linux version 2.6.18-238.el5xen (mockbuild@builder10.centos.org) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-48)) #1 SMP Thu Jan 13 16:41:45 EST 2011 BIOS-provided physical RAM map: Xen: 0000000000000000 - 0000000020800000 (usable) No mptable found. Built 1 zonelists. Total pages: 133120 Kernel command line: method=nfs:192.168.1.249:/home/netinstall Initializing CPU#0 PID hash table entries: 4096 (order: 12, 32768 bytes) Xen reported: 2812.790 MHz processor. Console: colour dummy device 80x25 Dentry cache hash table entries: 131072 (order: 8, 1048576 bytes) Inode-cache hash table entries: 65536 (order: 7, 524288 bytes) Software IO TLB disabled Memory: 496384k/532480k available (2529k kernel code, 27260k reserved, 1736k data, 196k init) Calibrating delay using timer specific routine.. 7050.28 BogoMIPS (lpj=14100572) Security Framework v1.0.0 initialized SELinux: Initializing. selinux_register_security: Registering secondary module capability Capability LSM initialized as secondary Mount-cache hash table entries: 256 CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line) CPU: L2 Cache: 1024K (64 bytes/line) CPU: Physical Processor ID: 0 CPU: Processor Core ID: 1 (SMP-)alternatives turned off Brought up 1 CPUs checking if image is initramfs... it is Grant table initialized NET: Registered protocol family 16 Brought up 1 CPUs PCI: setting up Xen PCI frontend stub ACPI: Interpreter disabled. Linux Plug and Play Support v0.97 (c) Adam Belay pnp: PnP ACPI: disabled xen_mem: Initialising balloon driver. usbcore: registered new driver usbfs usbcore: registered new driver hub PCI: System does not support PCI PCI: System does not support PCI NetLabel: Initializing NetLabel: domain hash size = 128 NetLabel: protocols = UNLABELED CIPSOv4 NetLabel: unlabeled traffic allowed by default NET: Registered protocol family 2 IP route cache hash table entries: 32768 (order: 6, 262144 bytes) TCP established hash table entries: 131072 (order: 9, 2097152 bytes) TCP bind hash table entries: 65536 (order: 8, 1048576 bytes) TCP: Hash tables configured (established 131072 bind 65536) TCP reno registered audit: initializing netlink socket (disabled) type=2000 audit(1307689628.858:1): initialized VFS: Disk quotas dquot_6.5.1 Dquot-cache hash table entries: 512 (order 0, 4096 bytes) Initializing Cryptographic API alg: No test for crc32c (crc32c-generic) ksign: Installing public key data Loading keyring - Added public key C099FB4D84A418B6 - User ID: CentOS (Kernel Module GPG key) io scheduler noop registered io scheduler anticipatory registered io scheduler deadline registered io scheduler cfq registered (default) pci_hotplug: PCI Hot Plug PCI Core version: 0.5 rtc: IRQ 8 is not free. Non-volatile memory driver v1.2 Linux agpgart interface v0.101 (c) Dave Jones brd: module loaded Xen virtual console successfully installed as xvc0 Bootdata ok (command line is method=nfs:192.168.1.249:/home/netinstall) Linux version 2.6.18-238.el5xen (mockbuild@builder10.centos.org) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-48)) #1 SMP Thu Jan 13 16:41:45 EST 2011 BIOS-provided physical RAM map: Xen: 0000000000000000 - 0000000020800000 (usable) No mptable found. Built 1 zonelists. Total pages: 133120 Kernel command line: method=nfs:192.168.1.249:/home/netinstall Initializing CPU#0 PID hash table entries: 4096 (order: 12, 32768 bytes) Xen reported: 2812.790 MHz processor. Console: colour dummy device 80x25 Dentry cache hash table entries: 131072 (order: 8, 1048576 bytes) Inode-cache hash table entries: 65536 (order: 7, 524288 bytes) Software IO TLB disabled Memory: 496384k/532480k available (2529k kernel code, 27260k reserved, 1736k data, 196k init) Calibrating delay using timer specific routine.. 7050.28 BogoMIPS (lpj=14100572) Security Framework v1.0.0 initialized SELinux: Initializing. selinux_register_security: Registering secondary module capability Capability LSM initialized as secondary Mount-cache hash table entries: 256 CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line) CPU: L2 Cache: 1024K (64 bytes/line) CPU: Physical Processor ID: 0 CPU: Processor Core ID: 1 (SMP-)alternatives turned off Brought up 1 CPUs checking if image is initramfs... it is Grant table initialized NET: Registered protocol family 16 Brought up 1 CPUs PCI: setting up Xen PCI frontend stub ACPI: Interpreter disabled. Linux Plug and Play Support v0.97 (c) Adam Belay pnp: PnP ACPI: disabled xen_mem: Initialising balloon driver. usbcore: registered new driver usbfs usbcore: registered new driver hub PCI: System does not support PCI PCI: System does not support PCI NetLabel: Initializing NetLabel: domain hash size = 128 NetLabel: protocols = UNLABELED CIPSOv4 NetLabel: unlabeled traffic allowed by default NET: Registered protocol family 2 IP route cache hash table entries: 32768 (order: 6, 262144 bytes) TCP established hash table entries: 131072 (order: 9, 2097152 bytes) TCP bind hash table entries: 65536 (order: 8, 1048576 bytes) TCP: Hash tables configured (established 131072 bind 65536) TCP reno registered audit: initializing netlink socket (disabled) type=2000 audit(1307689628.858:1): initialized VFS: Disk quotas dquot_6.5.1 Dquot-cache hash table entries: 512 (order 0, 4096 bytes) Initializing Cryptographic API alg: No test for crc32c (crc32c-generic) ksign: Installing public key data Loading keyring - Added public key C099FB4D84A418B6 - User ID: CentOS (Kernel Module GPG key) io scheduler noop registered io scheduler anticipatory registered io scheduler deadline registered io scheduler cfq registered (default) pci_hotplug: PCI Hot Plug PCI Core version: 0.5 rtc: IRQ 8 is not free. Non-volatile memory driver v1.2 Linux agpgart interface v0.101 (c) Dave Jones brd: module loaded Xen virtual console successfully installed as xvc0 Event-channel device installed. Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2 ide: Assuming 50MHz system bus speed for PIO modes; override with idebus=xx ide-floppy driver 0.99.newide usbcore: registered new driver hiddev usbcore: registered new driver usbhid drivers/usb/input/hid-core.c: v2.6:USB HID core driver PNP: No PS/2 controller found. Probing ports directly. i8042.c: No controller found. mice: PS/2 mouse device common for all mice md: md driver 0.90.3 MAX_MD_DEVS=256, MD_SB_DISKS=27 md: bitmap version 4.39 TCP bic registered Initializing IPsec netlink socket NET: Registered protocol family 1 NET: Registered protocol family 17 XENBUS: Device with no driver: device/vbd/51712 XENBUS: Device with no driver: device/vif/0 Initalizing network drop monitor service Write protecting the kernel read-only data: 498k Greetings. anaconda installer init version 11.1.2.224 starting mounting /proc filesystem... done creating /dev filesystem... done mounting /dev/pts (unix98 pty) filesystem... done mounting /sys filesystem... done anaconda installer init version 11.1.2.224 using /dev/xvc0 as console trying to remount root filesystem read write... done mounting /tmp as ramfs... done running install... running /sbin/loader