qcow2快照操做

1. 查看虚拟机快照
   virsh snapshot-list vmname
2. 查看快照的详细信息
   virsh snapshot-info vmname snapname
3. 建立内部快照
   virsh snapshot-create-as vmname snapname
4. 建立带内存内部快照
   virsh snapshot-create-as --migrate vmname snapname
5. 建立外部快照
   virsh snapshot-create-as vmname snapname --no-metadata --disk-only --atomic
6. commit到base镜像
   virsh blockcommit vmname vda --verbose --pivot --active
   7.pull到top镜像
   virsh blockpull vmname vda --wait --verbose
7. 在线rebase
   virsh qemu-monitor-command vmname '{"execute": "drive-backup", "arguments":{"device":"drive-virtio-disk0", "sync":"full", "target":"/path/imagename", "format":"qcow2"}}'
8. 离线rebaseqemu-img rebase -u -b /path/base /path/top