Comment 26 for bug 1836475

LGTM, thanks!

| ubuntu@juju-87625f-hloeung-66:~$ cp /etc/cron.weekly/update-notifier-common ~/
| ubuntu@juju-87625f-hloeung-66:~$ sudo apt-get update
| ...
| Get:8 http://us.archive.ubuntu.com/ubuntu bionic-proposed/main amd64 Packages [104 kB]
| ...
| ubuntu@juju-87625f-hloeung-66:~$ sudo apt-get install update-notifier-common
| ubuntu@juju-87625f-hloeung-66:~$ diff -Naurp ~/update-notifier-common /etc/cron.weekly/update-notifier-common
| --- /home/ubuntu/update-notifier-common 2021-08-26 00:27:43.687383953 +0000
| +++ /etc/cron.weekly/update-notifier-common 2021-08-23 22:33:23.000000000 +0000
| @@ -4,5 +4,12 @@ set -e
|
| [ -x /usr/lib/ubuntu-release-upgrader/release-upgrade-motd ] || exit 0
|
| -# Check to see whether there is a new version of Ubuntu available
| -/usr/lib/ubuntu-release-upgrader/release-upgrade-motd
| +sleep_then_check() {
| + # Sleep for up to an hour to spread the load of checking for updates on
| + # the Ubuntu infrastructure
| + sleep $(shuf -i 1-3600 -n 1)
| + # Check to see whether there is a new version of Ubuntu available
| + /usr/lib/ubuntu-release-upgrader/release-upgrade-motd
| +}
| +
| +sleep_then_check &
| ubuntu@juju-87625f-hloeung-66:~$ sudo /etc/cron.weekly/update-notifier-common
| ubuntu@juju-87625f-hloeung-66:~$ ps afxuww | grep sleep
| root 22110 0.0 0.0 7932 740 pts/0 S 00:29 0:00 \_ sleep 767
| ubuntu@juju-87625f-hloeung-66:~$ ls -la /var/lib/ubuntu-release-upgrader/release-upgrade-available
| -rw-r--r-- 1 root root 80 Aug 26 00:27 /var/lib/ubuntu-release-upgrader/release-upgrade-available
| ubuntu@juju-87625f-hloeung-66:~$ New release '20.04.2 LTS' available.
| Run 'do-release-upgrade' to upgrade to it.
|

The additional output from the end is when it ran, LP:1940011 is to see if we can silence that to reduce weekly cron spam.