How to use virsh to create snapshots for Debian 11
In this article, I'd like to discuss how to use virsh to create snapshots for a Debian 11 VM created with KVM or WebConsole.
Contents
Syntax
Let's take a look at syntax for available snapshot commands with virsh
$ virsh help | grep snapshot- snapshot-create Create a snapshot from XML snapshot-create-as Create a snapshot from a set of args snapshot-current Get or set the current snapshot snapshot-delete Delete a domain snapshot snapshot-dumpxml Dump XML for a domain snapshot snapshot-edit edit XML for a snapshot snapshot-info snapshot information snapshot-list List snapshots for a domain snapshot-parent Get the name of the parent of a snapshot snapshot-revert Revert a domain to a snapshot
snapshot-create
I recommend using snapshot-create-as which allows me to specify --name (name of snapshot), --description (some note for myself)
Here is Debian 11 vm I created earlier.
$ virsh list | egrep 'Name|d11vm' Id Name State 21 d11vm running
To create our first snapshot from d11vm:
$ virsh snapshot-create-as d11vm --name d11snap01 --description "First Snapshot" Domain snapshot d11snap01 created
I used d11snap01 for the name of snapshot and some note for myself.
snapshot-list
To see a list of snapshots from our d11vm:
$ virsh snapshot-list d11vm Name Creation Time State -------------------------------------------------- d11snap01 2021年08月22日 16:59:32 -0700 running
snapshot-info
To see more information on snapshot we're just created:
$ virsh snapshot-info d11vm --snapshotname d11snap01 Name: d11snap01 Domain: d11vm Current: yes State: running Location: internal Parent: - Children: 0 Descendants: 0 Metadata: yes
Did you notice that there is no description in the info? Well, I had to use following command to see the description
$ virsh snapshot-dumpxml d11vm --snapshotname d11snap01 | grep description <description>First Snapshot</description>
Now, let's make some changes on our vm (d11vm) then roll-back (revert) to our first snapshot
How about we install "curl" in the vm (d11vm) ?
$ ssh d11vm ... $ sudo apt update && sudo apt -y install curl ... $ which curl /usr/bin/curl
snapshot-revert
To rollback (revert) our vm (d11vm) to our first snapshot (d11snap01):
$ virsh snapshot-revert d11vm --snapshotname d11snap01
I did not see any message but we can check by log back into the vm (d11vm) and check if curl is installed.
$ ssh d11vm ... $ which curl (nothing)
That's what we expected. So roll-back (revert) was success!
snapshot-delete
So how do we delete a snapshot? Well, let's make another snapshot (d11snap02) before we delete one.
$ virsh snapshot-create-as d11vm --name d11snap02 --description "2nd Snapshot" Domain snapshot d11snap02 created $ virsh snapshot-list d11vm Name Creation Time State -------------------------------------------------- d11snap01 2021年08月22日 16:59:32 -0700 running d11snap02 2021年08月22日 17:17:51 -0700 running
To delete the 2nd snapshot (d11snap02):
$ virsh snapshot-delete d11vm --snapshotname d11snap02 Domain snapshot d11snap02 deleted $ virsh snapshot-list d11vm Name Creation Time State -------------------------------------------------- d11snap01 2021年08月22日 16:59:32 -0700 running
That's it! I hope this was useful introduction to virsh snapshot commands.