10 Automating Snapshots

Throughout this chapter, you must be root or able to sudo to become root.

Automating the snapshot process makes things a whole lot easier.

Automating the snapshot copy process¶

Perform this process on incus-primary. First thing you need to do is create a script that will run by a cron in /usr/local/sbin called "refresh-containers" :

sudo vi /usr/local/sbin/refreshcontainers.sh

The script is pretty minimal:

#!/bin/bash
# This script is for doing an lxc copy --refresh against each container, copying
# and updating them to the snapshot server.

for x in $(/var/lib/snapd/snap/bin/lxc ls -c n --format csv)
        do echo "Refreshing $x"
        /var/lib/snapd/snap/bin/lxc copy --refresh $x incus-snapshot:$x
        done

Make it executable:

sudo chmod +x /usr/local/sbin/refreshcontainers.sh

Change the ownership of this script to your incusadmin user and group:

sudo chown incusadmin.incusadmin /usr/local/sbin/refreshcontainers.sh

Set up the crontab for the incusadmin user to run this script, in this case at 10 PM:

crontab -e

Your entry will look like this:

00 22 * * * /usr/local/sbin/refreshcontainers.sh > /home/incusadmin/refreshlog 2>&1

Save your changes and exit.

This will create a log, in incusadmin's home directory, called "refreshlog," which will give you knowledge of whether your process worked or not. Very important!

The automated procedure will fail sometimes. This generally happens when a particular container fails to refresh. You can manually re-run the refresh with the following command (assuming rockylinux-test-9 here, is our container):

lxc copy --refresh rockylinux-test-9 incus-snapshot:rockylinux-test-9

Author: Steven Spencer

Contributors: Ezequiel Bruni, Ganna Zhyrnova