使用命令接口对KVM虚拟机进行简单的管理

一
KVM对用户提供的命令主要在/usr/bin/目录下
[root@centoskvm ~]# ls
/usr/bin/vir*
/usr/bin/virsh /usr/bin/virt-manager
/usr/bin/virt-clone /usr/bin/virt-pki-validate
/usr/bin/virt-convert /usr/bin/virt-top
/usr/bin/virt-host-validate
/usr/bin/virt-viewer
/usr/bin/virt-image /usr/bin/virt-who
/usr/bin/virt-install /usr/bin/virt-xml-validate

[root@centoskvm ~]# ls
/usr/bin/qe*
/usr/bin/qemu-img /usr/bin/qemu-io
/usr/bin/qemu-kvm

常用的命令有:virsh,virsh-install,virsh-clone,virsh-convert,virsh-image,qemu-img和qemu-kvm

二
virsh常用的管理命令
使用xml配置文件开启虚拟机
[root@centoskvm kvm]# virsh create
1003vm.xml
Domain 1003vm created from 1003vm.xml

列出虚拟机：
[root@centoskvm kvm]# virsh
list
Id Name State
----------------------------------------------------
13 1003vm running
Id和Name可以作为控制虚拟机的主键

列出域中全部的虚拟机：
[root@centoskvm kvm]# virsh
list --all
Id Name State
----------------------------------------------------
13 1003vm running
-
1001vm shut off

关闭虚拟机：
[root@centoskvm kvm]# virsh shutdown
13
或者
[root@centoskvm kvm]# virsh shutdown
1003vm

重启虚拟机：
[root@centoskvm kvm]#virsh reboot 13
或者
[root@centoskvm kvm]# virsh
reboot 1003vm

强制关闭虚拟机：（不建议使用，这样容易破坏虚拟机的文件系统）
[root@centoskvm kvm]#virsh destroy 13
或者
[root@centoskvm kvm]#
virsh destroy 1003vm

添加虚拟机：
[root@centoskvm
kvm]#virsh define
/home/kvm/1002vm.xml #根据主机配置文档添加虚拟机
Domain 1002vm defined from /home/kvm/1002vm.xml
[root@centoskvm kvm]# virsh
list --all
Id Name State
----------------------------------------------------
13 1003vm running
- 1001vm shut
off
-
1002vm shut off #1002vm已被添加到域中

移除虚拟机：
[root@centoskvm
kvm]#virsh undefine
1002vm
Domain 1002vm has been undefined
[root@centoskvm kvm]# virsh list
--all
Id Name State
----------------------------------------------------
13 1003vm running
- 1001vm shut
off
#1002vm已被从域中移除

导出虚拟机的配置信息xml文件
[root@centoskvm kvm]# virsh dumpxml
1003vm > ~/1003vm.xml
[root@centoskvm kvm]# cat
~/1003vm.xml
<domaintype='kvm' id='13'>
<name>1003vm</name>
<uuid>323286df-2fa9-9864-4754-b51df76bd336</uuid>
<memory
unit='KiB'>2097152</memory>
<currentMemory
unit='KiB'>2097152</currentMemory>
<vcpu
placement='static'>2</vcpu>
<os>
<type arch='x86_64'
machine='rhel6.2.0'>hvm</type>
<boot
dev='hd'/>
</os>
<features>
<acpi/>
<apic/>
<pae/>
</features>
<clock
offset='utc'/>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>restart</on_crash>
<devices>
<emulator>/usr/libexec/qemu-kvm</emulator>
<disk
type='file' device='disk'>
<driver name='qemu' type='raw' cache='none'/>
<source file='/home/kvm/1003vm.img'/>
<target dev='vda'
bus='virtio'/>
<shareable/>
<alias
name='virtio-disk0'/>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x05' function='0x0'/>
</disk>
<controller type='usb'
index='0'>
<alias name='usb0'/>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x01' function='0x2'/>
</controller>
<interface type='bridge'>
<mac
address='52:54:00:88:f8:03'/>
<source
bridge='br0'/>
<target dev='vnet0'/>
<model type='virtio'/>
<alias name='net0'/>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x03' function='0x0'/>
</interface>
<serial type='pty'>
<source path='/dev/pts/1'/>
<target port='0'/>
<alias name='serial0'/>
</serial>
<console type='pty'
tty='/dev/pts/1'>
<source path='/dev/pts/1'/>
<target type='serial'
port='0'/>
<alias name='serial0'/>
</console>
<input
type='tablet' bus='usb'>
<alias name='input0'/>
</input>
<input
type='mouse' bus='ps2'/>
<graphics type='vnc' port='5900'
listen='127.0.0.1'>
<listen type='address'
address='127.0.0.1'/>
</graphics>
<video>
<model type='cirrus' vram='9216'
heads='1'/>
<alias name='video0'/>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x02' function='0x0'/>
</video>
<memballoon model='virtio'>
<alias name='balloon0'/>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x06' function='0x0'/>
</memballoon>
</devices>
<seclabel type='dynamic'
model='selinux' relabel='yes'>
<label>system_u:system_r:svirt_t:s0:c97,c672</label>
<imagelabel>system_u:object_r:svirt_image_t:s0:c97,c672</imagelabel>
</seclabel>
</domain>

也可以使用xml配置来启动虚拟机：
[root@centoskvm kvm]# virsh shutdown 1003vm
[root@centoskvm
kvm]# virsh list
--all
Id
Name State
----------------------------------------------------
-
1003vm shut off
-
1001vm shut off

[root@centoskvm kvm]# virsh create ~/1003vm.xml
[root@centoskvm
kvm]# virsh list
--all
Id
Name State
----------------------------------------------------
14
1003vm running
-
1001vm shut off

三
使用命令接口创建虚拟机
创建镜像文件：
[root@centoskvm kvm]# qemu-img create -f qcow2 /home/kvm/1001vm.img
16G
查看img文件信息：
[root@centoskvm img]# qemu-img info 1001vm.img
image:
1001vm.img
file
format: qcow2
virtual size:
16G (17179869184 bytes)
disk size:
5.9G
cluster_size:
65536

其中参数 -f
表示镜像文件的格式[qcow2]，具体介绍如下：
[root@centoskvm img]# qemu-img
create --help
create: invalid option -- '-'
qemu-img version 0.12.1, Copyright (c) 2004-2008 Fabrice
Bellard
usage: qemu-img command [command options]
QEMU disk image utility

Command syntax:
check [-f fmt] filename
create [-f fmt] [-o options] filename
[size]
commit [-f fmt] [-t cache] filename
convert [-c] [-p] [-f
fmt] [-t cache] [-O output_fmt] [-o options] [-S sparse_size]
filename [filename2 [...]] output_filename
info [-f fmt] filename
snapshot [-l | -a
snapshot | -c snapshot | -d snapshot] filename
rebase [-f fmt] [-t cache] [-p] [-u] -b
backing_file [-F backing_fmt] filename
resize filename [+ | -]size

Command parameters:
'filename' is a disk image filename
'fmt' is the disk image format. It is
guessed automatically in most cases
'cache' is the cache mode used to write the
output disk image, the valid
options are: 'none',
'writeback' (default), 'writethrough' and 'unsafe'
'size' is the disk image size in bytes.
Optional suffixes
'k' or 'K' (kilobyte,
1024), 'M' (megabyte, 1024k), 'G' (gigabyte, 1024M)
and T (terabyte, 1024G)
are supported. 'b' is ignored.
'output_filename' is the destination disk
image filename
'output_fmt' is the destination
format
'options' is a comma separated list of
format specific options in a
name=value format. Use
-o ? for an overview of the options supported by the
used format
'-c' indicates that target image must be
compressed (qcow format only)
'-u' enables unsafe rebasing. It is assumed
that old and new backing file
match exactly. The image doesn't need a working
backing file before
rebasing in this case (useful for renaming the
backing file)
'-h' with or without a command shows this
help and lists the supported formats
'-p' show progress of command (only certain
commands)
'-S' indicates the consecutive number of
bytes that must contain only zeros
for qemu-img to create a sparse image during
conversion

Parameters to snapshot subcommand:
'snapshot' is the name of the snapshot to
create, apply or delete
'-a' applies a snapshot (revert disk to
saved state)
'-c' creates a
snapshot
'-d' deletes a snapshot
'-l' lists all snapshots in the given
image

Supported formats: raw cow qcow
vdi vmdk cloop dmg bochs vpc vvfat qcow2 qed parallels nbd blkdebug host_cdrom
host_floppy host_device file

常用的格式为raw和qcow2，推荐使用qcow2格式。
raw格式：可以简单、容易地导出到其它模拟器中，但是立即分配占用空间大。
qcow2格式：是qcow格式的升级版本，是目前最万能的格式。使用它可获得较小映像，也是虚拟池一直在使用的镜像格式，支持镜像快照，方便的恢复管理。

安装虚拟机客户操作系统：
[root@centoskvm img]#virt-install --name 1001vm --ram=1024 --arch=x86_64
--vcpus=2 --check-cpu --os-type=linux --os-variant='rhel6' -c
/home/mysoft/os/CentOS-6.2-x86_64-bin-DVD1.iso --disk
path=/home/img/1001vm.img,device=disk,bus=virtio,format=qcow2
--bridge=br0 --noautoconsole --vnc --vncport=5902
--vnclisten=0.0.0.0
[root@centoskvm img]# virt-install --help
Usage: virt-install --name NAME --ram RAM STORAGE INSTALL
[options]

Options:
--version show program's version number
and exit
-h, --help show this help message and
exit
--connect=URI Connect to
hypervisor with libvirt URI

General Options:
-n
NAME, --name=NAME
Name of the guest instance
-r
MEMORY, --ram=MEMORY
Memory to allocate for guest instance in
megabytes
--vcpus=VCPUS Number of vcpus to configure for your guest.
Ex:
--vcpus
5
--vcpus
5,maxcpus=10
--vcpus
sockets=2,cores=4,threads=2
--cpuset=CPUSET
Set which physical CPUs
domain can use.
--cpu=CPU
CPU model and features. Ex:
--cpu coreduo,+x2apic
--description=DESCRIPTION
Human
readable description of the VM to store in the
generated
XML.
--security=SECURITY
Set domain
security driver configuration.
--numatune=NUMATUNE
Tune NUMA
policy for the domain process.

Installation Method Options:
-c
CDROM, --cdrom=CDROM
CD-ROM
installation media
-l LOCATION,
--location=LOCATION
Installation source (eg, nfs:host:/path, http://host/path, ftp://host/path)
--pxe Boot from
the network using the PXE protocol
--import
Build guest
around an existing disk image
--init=INIT
Path to init binary for container guest.
Ex:
--init
/path/to/app (to contain an application)
--init
/sbin/init (for a full OS container)
--livecd
Treat the
CD-ROM media as a Live CD
-x EXTRA,
--extra-args=EXTRA
Additional
arguments to pass to the install kernel
booted
from --location
--initrd-inject=INITRD_INJECTIONS
Add given
file to root of initrd from --location
--os-type=DISTRO_TYPE
The OS
type being installed, e.g. 'linux', 'unix',
'windows'
--os-variant=DISTRO_VARIANT
The OS
variant being installed guests, e.g. 'fedora6',
'rhel5',
'solaris10', 'win2k'
--boot=BOOTOPTS
Optionally configure
post-install boot order, menu,
permanent
kernel boot, etc.

Storage Configuration:
--disk=DISKOPTS Specify storage with various options. Ex.
--disk
path=/my/existing/disk
--disk
path=/my/new/disk,size=5 (in gigabytes)
--disk
vol=poolname:volname,device=cdrom,bus=scsi,...
--nodisks
Don't set up any disks for
the guest.
--filesystem=FILESYSTEMS
Pass host
directory to the guest. Ex:
--filesystem /my/source/dir,/dir/in/guest
--filesystem template_name,/,type=template

Networking Configuration:
-w
NETWORK, --network=NETWORK
Configure
a guest network interface. Ex:
--network bridge=mybr0
--network
network=my_libvirt_virtual_net
--network
network=mynet,model=virtio,mac=00:11...
--nonetworks
Don't create network interfaces for the
guest.

Graphics Configuration:
--graphics=GRAPHICS
Configure
guest display settings. Ex:
--graphics vnc
--graphics
spice,port=5901,tlsport=5902
--graphics
none
--graphics
vnc,password=foobar,port=5910,keymap=ja
--noautoconsole
Don't automatically try to
connect to the guest
console

Device Options:
--serial=SERIALS
Configure a guest serial
device
--parallel=PARALLELS
Configure
a guest parallel device
--channel=CHANNELS
Configure a guest communication channel
--console=CONSOLES Configure a text console
connection between the guest
and host
--host-device=HOSTDEVS
Configure
physical host devices attached to the guest
--soundhw=SOUNDHW
Configure guest sound device emulation
--watchdog=WATCHDOG
Configure
a guest watchdog device
--video=VIDEO
Configure
guest video hardware.
--smartcard=SMARTCARD
Configure
a guest smartcard device. Ex:
--smartcard mode=passthrough

Virtualization Platform Options:
-v, --hvm
This guest should be a fully
virtualized guest
-p, --paravirt
This guest
should be a paravirtualized guest
--container
This guest should be a container guest
--virt-type=HV_TYPE
Hypervisor
name to use (kvm, qemu, xen, ...)
--arch=ARCH
The CPU architecture to simulate
--machine=MACHINE
The machine type to emulate
--noapic
Disables
APIC for fully virtualized guest (overrides
value in
os-type/os-variant db)
--noacpi
Disables
ACPI for fully virtualized guest (overrides
value in
os-type/os-variant db)
-u
UUID, --uuid=UUID
UUID for
the guest.

Miscellaneous Options:
--autostart
Have domain autostart on host boot up.
--print-xml
Print the generated domain XML rather than
define the
guest.
--print-step=XMLSTEP
Print XML
of a specific install step (1, 2, 3, all)
rather
than define the guest.
--noreboot
Don't boot guest after
completing install.
--wait=WAIT
Time to wait (in minutes)
--dry-run
Run through install process,
but do not create devices
or define
the guest.
--force
Forces
'yes' for any applicable prompts, terminates
for all
others
-q, --quiet
Suppress non-error output
--prompt
Request
user input for ambiguous situations or
required
options.
-d, --debug
Print debugging information

四 使用console登录虚拟机
[root@centoskvm img]#virsh list
Id Name State
----------------------------------------------------
13 1003vm running
[root@centoskvm img]# virshconsole 13
若出现无法从console登录的情况，会卡在“
Escape character is ^]”处无法继续。请从桌面以root登录做如下操作：
1、添加ttyS0的安全许可，允许root登录:
[root@1001vm
img]# echo "ttyS0" >>
/etc/securetty
[root@1001vm
~]# cat
/etc/securetty
console
vc/1
vc/2
。。。。。。
vc/10
vc/11
tty1
tty2
。。。。。。
tty11
ttyS0
2、在/etc/grub.conf文件中为内核添加参数:console=ttyS0
[root@1001vm ~]# cat /etc/grub.conf
# grub.conf generated by
anaconda
#
# Note that you do not have
to rerun grub after making changes to this file
# NOTICE:
You have a /boot partition.
This means that
# all kernel and initrd paths are relative to
/boot/, eg.
# root (hd0,0)
# kernel /vmlinuz-version ro
root=/dev/mapper/vg_1001vm-lv_root
# initrd /initrd-[generic-]version.img
#boot=/dev/vda
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS
(2.6.32-220.el6.x86_64)
root (hd0,0)
kernel /vmlinuz-2.6.32-220.el6.x86_64
ro root=/dev/mapper/vg_1001vm-lv_root rd_NO_LUKS
rd_LVM_LV=vg_1001vm/lv_root LANG=en_US.UTF-8 rd_NO_MD quiet
SYSFONT=latarcyrheb-sun16 rhgb crashkernel=auto
rd_LVM_LV=vg_1001vm/lv_swap KEYBOARDTYPE=pc
KEYTABLE=us rd_NO_DM console=ttyS0
initrd
/initramfs-2.6.32-220.el6.x86_64.img

3、在/etc/inittab中添加agetty:
S0:12345:respawn:/sbin/agetty ttyS0
115200
[root@1001vm ~]# cat /etc/inittab
# inittab is only used by
upstart for the default runlevel.
#。。。。。。。。。。。。。
#。。。。。。。。。。。。。
id:5:initdefault:
S0:12345:respawn:/sbin/agetty ttyS0
115200

4、重启客户虚拟机:
[root@1001vm
img]# reboot

此时，再次尝试console命令可以正常使用:
[root@centoskvm img]# virsh console 1001vm
Connected to domain 1001vm
Escape character is ^]
[ OK ]
Setting hostname 1001vm: [
OK ]
Setting up Logical Volume Management: 2
logical volume(s) in volume group "vg_1001vm" now active
[ OK ]
。。。。。。。。。。。。。。。。。。。。。。。。。。。。
。。。。。。。。。。。。。。。。。。。。。。。。。。。。
Starting atd: [ OK
]
Starting up CIM server: [ OK
]

CentOS release 6.2 (Final)
Kernel 2.6.32-220.el6.x86_64 on an x86_64

1001vm login: root
Password:
[root@1001vm ~]#