kvm 學習（二）

Linux下 如何通過命令行使用現有的鏡像創建、啟動kvm虛擬機

這里假定已經創建好了相應的鏡像：

eg：我這里制作的鏡像名稱為zu1-centos7.img

# lszu1-centos7.img  

1、拷貝這個鏡像到某一個目錄

cp zu1-centos7.img /data2/

2、編寫鏡像的配置文件，當然一般情況是從其他鏡像的配置文件拷貝一份，重新命名在修改

# cd /etc/libvirt/qemu   進入到鏡像配置文件目錄
# cp test2.xml test3.xml   test2.xml是其他鏡像存在的配置文件，test3.xml是當前準備啟動的鏡像的配置文件

test2.xml配置文件大體如下：

<!--
WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE
OVERWRITTEN AND LOST. Changes to this xml configuration should be made using:virsh edit test2
or other application using the libvirt API.
--><domain type='kvm'><name>test2</name>                     ---虛擬機名字，記得修改，隨便起什么名字都行，只要不跟其他虛擬機名字一樣就行<uuid>92047c95-c5b8-4e4d-916c-fb2218ca055f</uuid>    --uuid  記得修改，一般來說，把最好的四位數字重新修改一下，例如我把最后四位改成0001，具體效果看下個test3.xml文件<memory unit='KiB'>10485760</memory>      ---當前虛擬機使用內存，看自己情況是否需要修改<currentMemory unit='KiB'>10485760</currentMemory>   ---當前虛擬機可以使用的最大內存，使用內存不得超過這個內存，當使用內存不足的時候，可以在虛擬機里面動態調整內存。<vcpu placement='static'>1</vcpu><os><type arch='x86_64' machine='rhel6.6.0'>hvm</type>   ---架構，一般不用修改<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='qcow2' cache='none'/>   ---driver類型，需要跟鏡像的文件格式一致。以前老版本默認是raw類型，現在默認是qcow2類型。查看鏡像的文件格式在該配置文件的下面：<source file='/data1/iso/zu1-centos7.img'/>        --- 鏡像文件路徑<target dev='vda' bus='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/></disk><disk type='block' device='cdrom'><driver name='qemu' type='qcow2'/><target dev='hdc' bus='ide'/><readonly/><address type='drive' controller='0' bus='1' target='0' unit='0'/></disk><controller type='ide' index='0'><address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/></controller><controller type='usb' index='0' model='piix3-uhci'><address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/></controller><controller type='pci' index='0' model='pci-root'/><interface type='bridge'><mac address='52:54:00:5a:07:de'/><source bridge='br0'/><model type='virtio'/><address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>   ---這里的slot號記得修改  把最后兩位改成其他的就行，但不要跟其他的虛擬機配置的值一樣，同時，這個值不超過 0x0f</interface><serial type='pty'><target type='isa-serial' port='0'><model name='isa-serial'/></target></serial><console type='pty'><target type='serial' port='0'/></console><input type='tablet' bus='usb'><address type='usb' bus='0' port='1'/></input><input type='mouse' bus='ps2'/><input type='keyboard' bus='ps2'/><memballoon model='virtio'><address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/></memballoon></devices>
</domain>

3、查看鏡像的driver類型

# qemu-img info /data1/zu1-centos7.img
image: /data1/virtcentos/pool/zu1-centos7.img
file format: qcow2     ----這里就是鏡像的文件格式
virtual size: 20G (21474836480 bytes)
disk size: 18G
cluster_size: 65536
Format specific information:compat: 1.1lazy refcounts: true

4、修改test3.xml文件，如下：

<!--
WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE
OVERWRITTEN AND LOST. Changes to this xml configuration should be made using:virsh edit test2
or other application using the libvirt API.
--><domain type='kvm'><name>yjt</name>    ---這里改成了yjt<uuid>92047c95-c5b8-4e4d-916c-fb2218ca0001</uuid><memory unit='KiB'>10485760</memory><currentMemory unit='KiB'>10485760</currentMemory><vcpu placement='static'>1</vcpu><os><type arch='x86_64' machine='rhel6.6.0'>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='qcow2' cache='none'/><source file='/data2/zu1-centos7.img'/>    ---這里修改了鏡像的路徑<target dev='vda' bus='virtio'/><address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/></disk><disk type='block' device='cdrom'><driver name='qemu' type='qcow2'/><target dev='hdc' bus='ide'/><readonly/><address type='drive' controller='0' bus='1' target='0' unit='0'/></disk><controller type='ide' index='0'><address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/></controller><controller type='usb' index='0' model='piix3-uhci'><address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/></controller><controller type='pci' index='0' model='pci-root'/><interface type='bridge'><mac address='52:54:00:5a:07:de'/><source bridge='br0'/><model type='virtio'/><address type='pci' domain='0x0000' bus='0x00' slot='0x10' function='0x0'/>   這里改成了0x10，注意,該值不得超過0x0f</interface><serial type='pty'><target type='isa-serial' port='0'><model name='isa-serial'/></target></serial><console type='pty'><target type='serial' port='0'/></console><input type='tablet' bus='usb'><address type='usb' bus='0' port='1'/></input><input type='mouse' bus='ps2'/><input type='keyboard' bus='ps2'/><memballoon model='virtio'><address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/></memballoon></devices>
</domain>

5、定義虛擬機

# virsh define test3.xml  ---定義虛擬機跟上對應的文件即可

6、啟動虛擬機

virsh start yjt   ---yjt這個名字在配置文件定義的，也就是虛擬機的名字。

到這里就ok了。

如果虛擬機不要用了，可以使用如下方法銷毀

7、停止虛擬機

# virsh shutdown yjt   ---正常停止
# virsh destroy yjt    ---強制停止

8、取消虛擬機的定義，也就是刪除

# virsh undefine yjt   ---默認會刪除/etc/libvirt/qemu下的test3.xml文件

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