Host your own APT news#

APT news is used to deliver messages related to APT updates. However, it can also be used to display custom messages within the apt upgrade command to your users.

In this tutorial, you will learn how to host your own APT news and how to configure your Ubuntu machines to use it.

Install Multipass#

To avoid making any modifications to your live system during the tutorial, we will set up a virtual machine using Multipass. We are using Multipass because it allows us to launch VMs without needing any complicated setup. To install Multipass on your system, run the following command on your machine:

$ sudo snap install multipass

Note

You will need at least 10 Gigabytes of free space on your machine to launch the Multipass VM used in this tutorial.

Tutorial overview#

To demonstrate how APT news works, we will create three containers inside a Multipass VM. We will configure one of them to be the APT news server, and we will configure the other two to consume APT news from that server. It will look something like this:

Command snippets throughout this tutorial will include a shell prompt to make it clear on which machine the command will be executed.

Prompt	Machine
`you@yourcomputer:~$`	Your computer
`ubuntu@tutorial:~$`	Multipass VM named `tutorial`
`root@apt-news-server:~#`	LXD container named `apt-news-server`
`root@client-jammy:~#`	LXD container named `client-jammy`
`root@client-focal:~#`	LXD container named `client-focal`

Create the local VM and containers#

Let’s begin by launching an Ubuntu 24.04 Multipass VM with the following command:

you@yourcomputer:~$ multipass launch noble --disk 10G --name tutorial

Then we can access the VM using the multipass shell subcommand:

you@yourcomputer:~$ multipass shell tutorial

When you see “Welcome to Ubuntu 24.04 LTS” and the shell prompt changes to the following, you know that you’ve entered the VM.

ubuntu@tutorial:~$

We’re going to use LXD to set up our server and clients, so once we’re inside the VM, we can set up LXD with the default parameters:

ubuntu@tutorial:~$ lxd init --minimal

Now we will launch three containers inside the VM with the following commands. This may take a while since it will need to download the appropriate Ubuntu images.

ubuntu@tutorial:~$ lxc launch ubuntu-daily:noble apt-news-server
ubuntu@tutorial:~$ lxc launch ubuntu-daily:jammy client-jammy
ubuntu@tutorial:~$ lxc launch ubuntu-daily:focal client-focal

Configure the APT news server#

Now, let’s set up the apt-news-server container to serve APT news content. APT news content is formatted as a JSON file and served over HTTP(S). We can accomplish this by installing and configuring nginx to serve a properly formatted JSON file.

First, enter the apt-news-server container:

ubuntu@tutorial:~$ lxc shell apt-news-server
root@apt-news-server:~#

Inside apt-news-server, install nginx via apt. This will also start the HTTP server on port 80.

root@apt-news-server:~# apt install -y nginx

With nginx installed and running, we can author an APT news JSON file. Open /var/www/html/aptnews.json:

root@apt-news-server:~# nano /var/www/html/aptnews.json

and add the following content:

{
  "messages": [
    {
      "begin": "TODAY",
      "selectors": {
        "codenames": ["jammy"]
      },
      "lines": [
        "Hello 22.04 users!",
        "This is the APT news server."
      ]
    },
    {
      "begin": "TODAY",
      "lines": [
        "Hello everyone else!",
        "This is the APT news server."
      ]
    }
  ]
}

In nano, use CTRL + S and CTRL + X to save and exit, respectively.

That apt news configuration will show one message to systems running Ubuntu 22.04 (codename “jammy”) and will show a different message to all other systems.

The value of "begin" actually needs to be an ISO8601 formatted datetime string, and the message won’t be shown before the begin date or more than 30 days after the begin date. For the purposes of this tutorial you can quickly replace “TODAY” with today’s date in aptnews.json with the following command.

root@apt-news-server:~# sed -i "s/TODAY/$(date --iso-8601=seconds)/" /var/www/html/aptnews.json

You can double check that the command worked by looking at the new contents of the file.

root@apt-news-server:~# cat /var/www/html/aptnews.json

You should see that the begin field now has an appropriate value.

{
  "messages": [
    {
      "begin": "2024-07-30T16:35:19+00:00",
      "selectors": {
        "codenames": ["jammy"]
...

Now that our apt-news-server is configured, we can exit that container:

root@apt-news-server:~# exit
ubuntu@tutorial:~$

Configure the client machines to use the APT news server#

We need to configure both client machines to use the APT news server we just created. This is a single command on each container that we can run using lxc exec:

ubuntu@tutorial:~$ lxc exec client-jammy -- pro config set apt_news_url=http://apt-news-server/aptnews.json
ubuntu@tutorial:~$ lxc exec client-focal -- pro config set apt_news_url=http://apt-news-server/aptnews.json

That’s it! Now those containers will start displaying APT news in the output of apt upgrade.

Normally, the containers would fetch the latest APT news whenever an apt update is run, but at most once per day. For this tutorial, we’ll use pro refresh messages to force the containers to fetch the latest news right away.

In the Jammy container we expect to see the special message we set up for systems on Ubuntu 22.04. Let’s check this is working correctly by first entering the Jammy container:

ubuntu@tutorial:~$ lxc shell client-jammy

Then we can run these commands to see the custom APT news message:

root@client-jammy:~# pro refresh messages
root@client-jammy:~# apt upgrade

The output of apt upgrade should look like this.

Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Calculating upgrade... Done
#
# Hello 22.04 users!
# This is the APT news server.
#
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

Since this is what we expected, we can now exit the container:

root@client-jammy:~# exit
ubuntu@tutorial:~$

In the Focal client container we expect to see the other message. Let’s check that by entering the Focal container:

ubuntu@tutorial:~$ lxc shell client-focal

Then run these commands again to see the APT news message:

root@client-focal:~# pro refresh messages
root@client-focal:~# apt upgrade

The output of apt upgrade should look like this.

Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Calculating upgrade... Done
#
# Hello everyone else!
# This is the APT news server.
#
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

Once again, this is exactly what we expected to see, so everything is working correctly! Now we can exit this container:

root@client-focal:~# exit
ubuntu@tutorial:~$

Clean up#

Congratulations! This tutorial demonstrated the basics of how an APT news server can be set up and used by other Ubuntu machines.

Now that the tutorial is over, you can exit out of the Multipass VM:

ubuntu@tutorial:~$ exit
you@yourcomputer:~$

and delete it:

you@yourcomputer:~$ multipass delete --purge tutorial