Registering Ubuntu 20.04, 22.04 and 24.04 Clients

This section contains information about registering clients running Ubuntu 20.04 LTS, 22.04 LTS and 24.04 LTS operating systems.

Bootstrapping is supported for starting Ubuntu clients and performing initial state runs such as setting repositories and performing profile updates. However, the root user on Ubuntu is disabled by default, so to use bootstrapping, you require an existing user with sudo privileges for Python.

Canonical does not endorse or support Uyuni.

1. Add Software Channels

Before you register Ubuntu clients to your Uyuni Server, you need to add the required software channels, and synchronize them.

In the following section, descriptions often default to the x86_64 architecture. Replace it with other architectures if appropriate.

The channels you need for this procedure are:

Table 1. Ubuntu Channels - CLI
OS Version Base Channel Main Channel Updates Channel Security Channel Client Channel

Ubuntu 24.04

ubuntu-2404-pool-amd64-uyuni

ubuntu-2404-amd64-main-uyuni

ubuntu-2404-amd64-main-updates-uyuni

ubuntu-2404-amd64-main-security-uyuni

ubuntu-2404-amd64-uyuni-client

Ubuntu 22.04

ubuntu-2204-pool-amd64-uyuni

ubuntu-2204-amd64-main-uyuni

ubuntu-2204-amd64-main-updates-uyuni

ubuntu-2204-amd64-main-security-uyuni

ubuntu-2204-amd64-uyuni-client

Ubuntu 20.04

ubuntu-2004-pool-amd64-uyuni

ubuntu-2004-amd64-main-uyuni

ubuntu-2004-amd64-main-updates-uyuni

ubuntu-2004-amd64-main-security-uyuni

ubuntu-2004-amd64-uyuni-client

Version 20.04 also requires the Universe channels:

Table 2. Ubuntu 20.04 Universe Channels - CLI
Ubuntu 20.04  

Universe Channel

ubuntu-2004-amd64-universe-uyuni

Universe Updates Channel

ubuntu-2004-amd64-universe-updates-uyuni

Universe Security Updates Channel

ubuntu-2004-amd64-universe-security-uyuni

Universe Backports Channel

ubuntu-2004-amd64-universe-backports-uyuni
Procedure: Adding Software Channels at the Command Prompt

  1. At the command prompt on the Uyuni Server, as root, use the spacewalk-common-channels command to add the appropriate channels:

    spacewalk-common-channels \
<base_channel_label> \
<child_channel_label_1> \
<child_channel_label_2> \
... <child_channel_label_n>

  2. If automatic synchronization is turned off, synchronize the channels:

    spacewalk-repo-sync -p <base_channel_label>

  3. Ensure the synchronization is complete before continuing.

You need all the new channels fully synchronized before bootstrapping any Ubuntu client.

2. Mirror Ubuntu ESM packages

Canonical provides Expanded Security Maintenance (ESM) packages for Ubuntu Pro users and customers. These packages offer longer maintenance (10 to 12 years) for several operating system components and selected applications.

These repositories can also be synchronized within Uyuni if you extract the required GPG keys and your personal Bearer Token from a system registered to Ubuntu Pro.

2.1. Extract GPG keys and Bearer Token

Register an Ubuntu host with Ubuntu Pro. You will find your personal registration token in the Ubuntu Pro Dashbaord. An Ubuntu One acconut is required for this.

sudo apt-get install ubuntu-advantage-tools
sudo pro attach <perosnal_token>

After registration, you will find the Bearer Token in the file /etc/apt/auth.conf.d/90ubuntu-advantage:

machine esm.ubuntu.com/apps/ubuntu/ login bearer password <token>  # ubuntu-pro-client
machine esm.ubuntu.com/infra/ubuntu/ login bearer password <token>  # ubuntu-pro-client

One dedicated bearer token is used per repository.

Configure the following repositories within Uyuni:

2.2. Configure Ubuntu ESM repositories

Use the following URLs for creating the repositories:

Table 3. Ubuntu ESM repositories
URL Description

https://bearer:<token>@esm.ubuntu.com/infra/ubuntu/dists/<release>-infra-updates/main/binary-<arch>/

Operating system functional updates

https://bearer:<token>@esm.ubuntu.com/infra/ubuntu/dists/<release>-infra-security/main/binary-<arch>/

Operating system security updates

https://bearer:<token>@esm.ubuntu.com/apps/ubuntu/dists/<release>-apps-updates/main/binary-<arch>/

Application functional updates

https://bearer:<token>@esm.ubuntu.com/apps/ubuntu/dists/<release>-apps-security/main/binary-<arch>/

Application security updates

Replace <token> with your personal Bearer Token. Also, arch and release must be replaced with one of the following values:

Table 4. Ubuntu ESM architectures and releases
Architectures Releases

amd64, arm64, armel, armhf, i386, powerpc, ppc64el, s390x

bionic, focal, jammy, noble, trusty, xenial

In order for Uyuni to synchronize the repositories, the corresponding GPG keys (ubuntu-advantage-esm-infra-trusty.gpg, ubuntu-advantage-esm-apps.gpg) must be imported. These are located on a system registered with Ubuntu Pro under /etc/apt/trusted.gpg.d. Copy these files to the Uyuni system and import them as follows:

mgradm gpg add /path/to/gpg.key

Create the appropriate child channels below already synchronized Ubuntu parent channels. After that, repositories can be synchronized.

The procedure shown here can be used to circumvent the subscription limitations - however, this constitutes a breach of the Terms of Service and may have legal consequences. There must always be sufficient subscriptions for the number of systems used.

3. Check Synchronization Status

Procedure: Checking Synchronization Progress From the Web UI

  1. In the Uyuni Web UI, navigate to Software  Manage  Channels, then click the channel associated to the repository.

  2. Navigate to the Repositories tab, then click Sync and check Sync Status.

Procedure: Checking Synchronization Progress From the Command Prompt

  1. At the command prompt on the Uyuni Server, as root, use the tail command to check the synchronization log file:

    tail -f /var/log/rhn/reposync/<channel-label>.log

  2. Each child channel generates its own log during the synchronization progress. You need to check all the base and child channel log files to be sure that the synchronization is complete.

Ubuntu channels can be very large. Synchronization can sometimes take several hours.

4. Manage GPG Keys

Clients use GPG keys to check the authenticity of software packages before they are installed. Only trusted software can be installed on clients.

Trusting a GPG key is important for security on clients. It is the task of the administrator to decide which keys are needed and can be trusted. Because a software channel cannot be used when the GPG key is not trusted, the decision of assigning a channel to a client depends on the decision of trusting the key.

For more information about GPG keys, see GPG Keys.

5. Root Access

The root user on Ubuntu is disabled by default for SSH access.

To be able to onboard using a regular user, you need to edit the sudoers file.

This issue happens with self-installed versions of Ubuntu. If the default user has been granted administrative privileges during installation time, a password is required to perform privilege escalation using sudo. With cloud instances this does not happen because cloud-init automatically creates a file under /etc/sudoers.d and grants privilege escalation through sudo without the need for a password.

5.1. Grant Root User Access

Procedure: Granting Root User Access

  1. On the client, edit the sudoers file:

    sudo visudo

    Grant sudo access to the user by adding this line at the end of the sudoers file. Replace <user> with the name of the user that is bootstrapping the client in the Web UI:

    <user>  ALL=NOPASSWD: /usr/bin/python, /usr/bin/python2, /usr/bin/python3, /var/tmp/venv-salt-minion/bin/python

This procedure grants root access without requiring a password, which is required for registering the client. When the client is successfully installed it runs with root privileges, so the access is no longer required. We recommend that you remove the line from the sudoers file after the client has been successfully installed.

5.2. Bootstrap as Install-created User via SSH

To bootstrap an Ubuntu client via SSH you must add the install-created user to the sudo group. Then run the bootstrap script from the client.

Procedure: Adding Install-created User to sudo Group and Bootstrapping via SSH

  1. On the client, as root, run from the command line (replace <username> with the name of the install-created user):

    sudo usermod -aG sudo <username>

  2. Bootstrap the client system from its command line (replace <SERVER_FQDN> with the fully qualified domain name of the Uyuni Server):

    sudo su -
curl -Sks https://<SERVER_FQDN>/pub/bootstrap/bootstrap-script.sh | /bin/bash

Ubuntu can only be bootstrapped using the corresponding Ubuntu bootstrap script run from the client system’s command line after issuing sudo su - as above. It cannot be bootstrapped via the Uyuni Web UI due to the fact that the root user is disabled on Ubuntu by default, and that the Web UI does not permit for privilege escalation of the Ubuntu install-created user.

6. Register Clients

To register your clients, you need a bootstrap repository. By default, bootstrap repositories are automatically created, and regenerated daily for all synchronized products. You can manually create the bootstrap repository from the command prompt, using this command:

mgr-create-bootstrap-repo

For more information on registering your clients, see Client Registration.