openstack image virsual size 10G太大

 处理方法如下，但是这种方法产生的镜像是不能工作的。这个方法不可行了。请参考https://www.cnblogs.com/fengrenzw/p/3339915.html

1. You need to convert the qcow2 image to raw
   qemu-img convert -O raw guest.img guest.raw
2. Then resize the raw file
   qemu-img resize guest.raw 3G
3. Then convert it back to qcow2
   qemu-img convert -O qcow2 -o compat=0.10 guest.raw guest.img
4. Then run the guest and resize your file system