版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/linzhaolove/article/details/52209477
声明
此文档只做学习交流使用,请勿用作其他商业用途
author : 朝阳_tony
E-mail : [email protected]
Create Date: 2016-8-15 10:24:05
Last Change: 2016-8-15 11:14:17
转载请注明出处：http://blog.csdn.net/linzhaolover
摘要
在云计算Iaas层中，客户对kvm中image的需求格式各样，我可能就做一个基础的image，然后在上面再安装各类package，以适应不同的业务需求；但是，每个人对image的磁盘分区大小，又有不同的需求，这就需要从外面更改磁盘配置才行，下面就简单介绍一下，我采用的方法，方便大家学习交流
准备image
openstack 支持的image比较多，有qcow2 还有raw，我的qcow2 ，所以image后缀是qcow2
glance image-download --file old_image.qcow2 image_uuid查看磁盘分区
# qemu-img info old_image.qcow2
image: old_image.qcow2
file format: qcow2
virtual size: 20G (21474836480 bytes) ##虚拟磁盘大小是20G
disk size: 1.7G ##当前实际文件大小1.7G
cluster_size: 65536
Format specific information:
compat: 0.10
# virt-filesystems --long -h --all -a old_image.qcow2
Name Type VFS Label MBR Size Parent
/dev/sda1 filesystem ext4 - - 16G - #系统盘，也就是根目录
/dev/sda2 filesystem unknown - - 1.0K -
/dev/sda5 filesystem swap - - 4.0G -
/dev/sda1 partition - - 83 16G /dev/sda # 系统盘，一会我们扩增这个磁盘
/dev/sda2 partition - - 05 1.0K /dev/sda
/dev/sda5 partition - - 82 4.0G /dev/sda
/dev/sda device - - - 20G -创建新的空image
qemu-img create -f qcow2 newdisk.qcow2 100G
Formatting 'newdisk.qcow2', fmt=qcow2 size=107374182400 encryption=off cluster_size=65536 lazy_refcounts=off进行磁盘扩展
注意，由于我的image磁盘只是简单分区，没有lvm分区，所以一个–expand 足矣
virt-resize --expand /dev/sda1 old_image.qcow2 newdisk.qcow
Examining old_image.qcow2 ...
**********
Summary of changes:
/dev/sda1: This partition will be resized from 16.0G to 96.0G. The
filesystem ext4 on /dev/sda1 will be expanded using the 'resize2fs'
method.
/dev/sda2: This partition will be left alone.
**********
Setting up initial partition table on newdisk.qcow2 ...
Copying /dev/sda1 ...
100% ⟦▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒⟧ 00:00
Copying /dev/sda2 ...
100% ⟦▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒⟧ 00:00
Expanding /dev/sda1 using the 'resize2fs' method ...
Resize operation completed with no errors. Before deleting the old disk,
carefully check that the resized disk boots and works correctly.
# virt-filesystems --long -h --all -a newdisk.qcow2
Name Type VFS Label MBR Size Parent
/dev/sda1 filesystem ext4 - - 96G - #新的系统盘大小
/dev/sda2 filesystem unknown - - 1.0K -
/dev/sda5 filesystem swap - - 4.0G -
/dev/sda1 partition - - 83 96G /dev/sda # 新系统盘大小
/dev/sda2 partition - - 05 1.0K /dev/sda
/dev/sda5 partition - - 82 4.0G /dev/sda
/dev/sda device - - - 100G -压缩新的image
查看新image大小
qemu-img info newdisk.qcow2
image: newdisk.qcow2
file format: qcow2
virtual size: 100G (107374182400 bytes)
disk size: 5.7G # 由1.7G变成5.7G ，这有点大
cluster_size: 65536
Format specific information:
compat: 1.1
lazy refcounts: false压缩转换image
由于我的image是qcow2的格式，在输出我依然想适用qcow2，所以在-O qcow2 时候输出qcow2.
qemu-img convert -c -O qcow2 newdisk.qcow2 compress_newdisk.qcow2
qemu-img info compress_newdisk.qcow2
image: compress_newdisk.qcow2
file format: qcow2
virtual size: 100G (107374182400 bytes)
disk size: 575M # 变小了不少，这样导入glance也是很方便使用
cluster_size: 65536
Format specific information:
compat: 1.1
lazy refcounts: false* Reference : *
http://serverfault.com/questions/38456/online-resize-of-mounted-ext3-logical-volume
http://libguestfs.org/virt-resize.1.html