|
1、概述 实验目的：通过一个基础镜像（node.img），里面把各个虚拟机都需要的环境都搭建好，然后基于这个镜像建立起一个个增量镜像，每个增量镜像对应一个虚拟机，虚拟机对镜像中所有的改变都记录在增量镜像里面，基础镜像始终保持不变。 功能：节省磁盘空间，快速复制虚拟机。 环境： 基本镜像文件：node.img 虚拟机ID：node 增量镜像文件：node4.img 虚拟机ID：node4 要求：以基本镜像文件node.omg为基础，创建一个镜像文件node4.img，以此创建一个虚拟机机node4，虚拟机node4的改变将存储于node4.img中。 2、创建增量镜像文件 [root@target kvm_node]#qemu-img create -b node.img -f qcow2 node4.img [root@target kvm_node]# qemu-img info node4.img image: node4.img file format: qcow2 virtual size: 20G (21495808000 bytes) disk size: 33M cluster_size: 65536 backing file: node.img (actual path: node.img) #注：该实验只是针对qcow2格式的镜像文件，未测试raw格式的镜像文件是否可行。 3、创建虚拟机node4的XML配置文件 [root@target kvm_node]# cp /etc/libvirt/qemu/node.xml /etc/libvirt/qemu/node4.xml [root@target kvm_node]# vim /etc/libvirt/qemu/node4.xml <domain type='kvm'> <name>node4</name> #node4的虚拟机名，须修改，否则与基本虚拟机冲突 <uuid>4b7e91eb-6521-c2c6-cc64-c1ba72707fe4</uuid> #node4的UUID，必须修改，否则与基本虚拟机冲突 <memory>524288</memory> <currentMemory>524288</currentMemory> <vcpu cpuset='0-1'>2</vcpu> <os> <type arch='x86_64' machine='rhel5.4.0'>hvm</type> <boot dev='hd'/> </os> <features> <acpi/> <apic/> <pae/> </features> <clock offset='localtime'/> <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'/> <source file='/virhost/kvm_node/node4.img'/> #将原指向/virhost/kvm_node/node.img改为node4.img <target dev='vda' bus='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </disk> <interface type='bridge'> <mac address='54:52:00:69:d5:f4'/> #修改网卡MAC，防止冲突 <source bridge='br0'/> <model type='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> <interface type='bridge'> <mac address='54:52:00:69:d5:e4'/> #修改网卡MAC，防止冲突 <source bridge='br0'/> <model type='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/> </interface> <serial type='pty'> <target port='0'/> </serial> <console type='pty'> <target type='serial' port='0'/> </console> <input type='mouse' bus='ps2'/> <graphics type='vnc' port='5904' autoport='no' listen='0.0.0.0' passwd='xiaobai'> <listen type='address' address='0.0.0.0'/> </graphics> <video> <model type='cirrus' vram='9216' 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='0x06' function='0x0'/> </memballoon> </devices> </domain> 4、根据xml配置定义虚拟机node4 [root@target kvm_node]#virsh define /etc/libvirt/qemu/node4.xml [root@target kvm_node]#virsh start node4 5、测试 [root@target kvm_node]# du -h node.img 6.3G node.img [root@target kvm_node]# du -h node4.img 33M node4.img [root@node4 ~]# dd if=/dev/zero of=test bs=1M count=200 #在虚拟机node4上增量200M大小文件 200+0 records in 200+0 records out 209715200 bytes (210 MB) copied, 1.00361 seconds, 209 MB/s [root@target kvm_node]# du -h node.img #基本镜像文件node.img大小未变 6.3G node.img [root@target kvm_node]# du -h node.img #增量镜像文件node4.img增加200M了 234M node4.img (责任编辑：IT) |