There are several methods to update Ubuntu. These methods include package updates via the desktop, the unattended upgrade script, and good old Apt. As the title suggests, this post explores the last option using Cron.
Using the Apt command via Cron is mainly intended if you have installed a cut-down, customised or server version of Ubuntu. Conversely, Desktop users using the full install do not need to worry since the GUI automatically handles updates.
You should use the unattended upgrade script if you want to write the details and changes to the log files and send a mail report to a system admin user. However, this can be scripted using Bash if you wish.
The unattended-upgrades script in Ubuntu is handy when you want to:
- Do a dry run of an upgrade without actually installing anything.
- Handle security and non-security updates separately.
Therefore, this post is mainly intended for Ubuntu server users with a lightweight install. Thus using Apt and Cron would be a perfect fit and a no-frills approach.
As a matter of caution – upgrades can potentially break things—equally; it’s safer to be up-to-date.
Table of Contents
Let’s get started!
First, open Cron using the following command:
sudo crontab -eNote that you need to run this command using sudo. Alternatively, you need to be logged in as root.
Next, add the following lines using your favourite text editor and save:
0 17 * * 7 /usr/bin/apt update
0 18 * * 7 /usr/bin/apt upgrade -q -y
0 19 * * 7 /usr/bin/apt autocleanThe Apt update command only gets the information about the latest version of packages available for your system. While the Apt upgrade command on Ubuntu downloads and upgrades the package to the new version.
Autoclean clears the local repository of retrieved package files. But it only removes files that can no longer be downloaded and are effectively useless.
You can set your Cron to run the Ubuntu APT updates anytime. The example above runs the upgrade on Sundays starting at 17:00, then at 18:00 and finally at 19:00.
Using Ansible?
Ansible allows for easy automation. For example, you can add the following to your playbook to update Ubuntu using Apt and Cron:
tasks:
#
# Add update cron
#
- name: Update
become: yes
become_method: sudo
cron:
name: "update"
user: "root"
weekday: "7"
minute: "0"
hour: "19"
job: "/usr/bin/apt update -q -y"
state: present
#
# Add upgrade cron
#
- name: Upgrade
become: yes
become_method: sudo
cron:
name: "upgrade"
user: "root"
weekday: "7"
minute: "0"
hour: "20"
job: "/usr/bin/apt upgrade -q -y"
state: present
#
# Add autoclean cron
#
- name: Autoclean
become: yes
become_method: sudo
cron:
name: "autoclean"
user: "root"
weekday: "7"
minute: "0"
hour: "23"
job: "/usr/bin/apt autoclean"
state: presentWrapping Up
You have learned the differences between Apt updates using Cron, the desktop GUI update method, and Ubuntu’s unattended-upgrades script. In addition, you learned how to update, upgrade and auto-clean your Apt cache using Cron in Ubuntu.
