#### script installation virtual machine

#!/bin/bash
virt-install \
--cdrom /home/kiosk/Desktop/rhel-server-7.3-x86_64-dvd.iso \
--ram 1024 \
--cpus 1 \
--disk /var/lib/libvirt/images/test.qcow2,bus=virtio,size=9 \ ##I don't know. Wait a minute.
--name test \
--network bridge=br0,model=virtio &	##Instead of writing the model, install it and read it. Write it accordingly.

## Use this script again to install the virtual opportunity to report errors because of the test virtual machine
## Without looking at the output, & >/dev/null

######## Virtual Machine Management Command

virt-manager		##Boot-up Virtual Machine Manager
virsh list		##Display a running virtual machine
virsh list --all	##View all virtual machines
virsh start desktop	##open
virsh  shutdown desktop	##Normal shutdown of virtual machines	##Must be in the system
virsh destroy desktop	##force close
virt-viewer desktop	##Display Virtual Machine
virsh undefine test	##Delete virtual machines

Rehabilitation of Simulated Virtual Machines at Home
Prepare an installed virtual machine

mv /etc/libvirt/qemu/test.xml  /mnt/		##Hardware information
mv /var/lib/libvirt/images/test.qcow2  /mnt/	##Hard disk

Delete the installed virtual machine in the virtual machine manager to simulate the recovery process.

cd /mnt	
virsh	create	test.xml		##Start the virtual machine with hardware message (once shut down, no more)

The following errors will occur during the operation:
error: Cannot access storage file '/var/lib/libvirt/images/test.qcow2' (as uid:107, gid:107): No such file or directory
Solution:

mv /mnt/test.qcow2  /var/lib/libvirt/images/

virsh define test.xml			##Permanent Restoration Virtual Machine

#### Virtual Machine Snapshot####

qemu-img create -f qcow2 -b test.qcow2 node1

################ How to Create Virtual Machines with Scripts
The script content:

#!/bin/bash
qemu-img create -f qcow2 -b \
/var/lib/libvirt/images/$1.qcow2 \	##$1 is an existing virtual machine
/var/lib/libvirt/images/$2.qcow2	##$2 is snapshot.

virt-install \
--name $2 \
--ram 1024 \
--cpus 1 \
--disk /var/lib/libvirt/images/$2.qcow2,bus=virtio \
--network bridge=br0,model=virtio \
--import &

######### Using script reset virtual machine

#!/bin/bash
virsh destroy $1
rm -fr /var/lib/libvirt/images/$1.qcow2		##$1 is a snapshot and $2 is a master.
qemu-img create -f qcow2 -b /var/lib/libvirt/images/$2.qcow2 /var/lib/libvirt/images/$1.qcow2
virsh start $1
virt-viewer $1 &