Uyuni Server Migration to a Containerized Environment

1. Requirements and Considerations

1.1. General

To migrate a Uyuni 4.3 Server to a container, you require a new machine with SL Micro 6.1 or SUSE Linux Enterprise Server 15 SP7 and mgradm installed.
An in-place migration from Uyuni 4.3 to 2025.05 is not supported, regardless of whether the chosen host operating system is SL Micro 6.1 or SUSE Linux Enterprise Server 15 SP7.
Before migrating from Uyuni 4.3 to 2025.05, any existing traditional clients including the traditional proxies must be migrated to Salt. For more information about migrating traditional Uyuni 4.3 clients to Salt clients, see https://documentation.suse.com/suma/4.3/en/suse-manager/client-configuration/contact-methods-migrate-traditional.html.
Traditional contact protocol is no longer supported in Uyuni 5.0 and later.

This guide only covers the migration from Uyuni 4.3 to 2025.05. Migrating an existing Uyuni 2025.05 instance to the same version while switching the host operating system from SL Micro 6.1 to SUSE Linux Enterprise Server 15 SP7, or vice versa, is not handled by the mgradm migrate command.

1.2. Hostnames

The current migration procedure does not include functionality for renaming hostnames. As a result, the fully qualified domain name (FQDN) of the new server will remain the same as that of the old server.
The IP address must remain unchanged to ensure that the clients can contact the server.

After the migration, it will be necessary to manually update the DHCP and DNS records to point to the new server.

1.3. GPG Keys

Self trusted GPG keys are not migrated.
GPG keys that are trusted in the RPM database only are not migrated. Thus synchronizing channels with spacewalk-repo-sync can fail.
The administrator must migrate these keys manually from the 4.3 installation to the container host after the actual server migration.
Procedure: Manual Migration of the 4.3 GPG Keys to New Server
1. Copy the keys from the 4.3 server to the container host of the new server.
2. Later, add each key to the migrated server with the command mgradm gpg add <PATH_TO_KEY_FILE>.

2. Migration

2.1. Initial Preparation on the Old 4.3 Server

The migration can take a very long time depending on the amount of data that needs to be replicated.

To reduce downtime it is possible to run the migration multiple times in a process of initial replication, re-replication, or final replication and switch over while all the services on the old server can stay up and running.

Only during the final migration the processes on the old server need to be stopped.

For all non-final replications add the parameter --prepare to prevent the automatic stopping the services on the old server. For example:

mgradm migrate podman <oldserver.fqdn> --prepare

Do not pre-install Uyuni on the prepared SLE Micro 6.1 or SUSE Linux Enterprise Server 15 SP7 system. The migration process is designed to perform the server installation automatically. Running mgradm install and then mgradm migrate is not supported and will lead to an unsupported system state.

Procedure: Initial Preparation on the 4.3 Server

Stop the Uyuni services:
```
spacewalk-service stop
```
Stop the PostgreSQL service:
```
systemctl stop postgresql
```

2.2. SSH Connection Preparation

Procedure: Preparing the SSH Connection

Ensure that for root an SSH key exists on the new 2025.05 server. If a key does not exist, create it with:
```
ssh-keygen -t rsa
```

The SSH configuration and agent should be ready on the new server for a connection to the 4.3 server that does not prompt for a password.

eval $(ssh-agent); ssh-add

To establish a connection that does not prompt for a password, the migration script relies on an SSH agent running on the new server. If the agent is not active yet, initiate it by running eval $(ssh-agent). Then add the SSH key to the running agent with ssh-add followed by the path to the private key. You will be prompted to enter the password for the private key during this process.

Copy the public SSH key to the Uyuni 4.3 Server (<oldserver.fqdn>) with ssh-copy-id. Replace <oldserver.fqdn> with the FQDN of the 4.3 server:
```
ssh-copy-id <old server.fqdn>
```
The SSH key will be copied into the old server’s ~/.ssh/authorized_keys file. For more information, see the ssh-copy-id manpage.
Establish an SSH connection from the new server to the old Uyuni Server to check that no password is needed. Also there must not by any problem with the host fingerprint. In case of trouble, remove old fingerprints from the ~/.ssh/known_hosts file. Then try again. The fingerprint will be stored in the local ~/.ssh/known_hosts file.

2.3. Perform the Migration

When planning your migration from Uyuni 4.3 to Uyuni 2025.05, ensure that your target instance meets or exceeds the specifications of the old setup.

This includes, but is not limited to, memory (RAM), CPU Cores, Storage, and Network Bandwidth.

Procedure: Performing the Migration

This step is optional. If custom persistent storage is required for your infrastructure, use the mgr-storage-server tool.
- For more information, see mgr-storage-server --help. This tool simplifies creating the container storage and database volumes.
- Use the command in the following manner:
  mgr-storage-server <storage-disk-device> [<database-disk-device>]
  For example:
  mgr-storage-server /dev/nvme1n1 /dev/nvme2n1
  This command will create the persistent storage volumes at /var/lib/containers/storage/volumes.
  
  For more information, see Persistent Container Volumes.
Execute the following command to install a new Uyuni server. Replace <oldserver.fqdn> with the FQDN of the 4.3 server:
```
mgradm migrate podman <oldserver.fqdn>
```
Migrate trusted SSL CA certificates.

2.3.1. Migration of the Certificates

Trusted SSL CA certificates that were installed as part of an RPM and stored on Uyuni 4.3 in the /usr/share/pki/trust/anchors/ directory will not be migrated. Because SUSE does not install RPM packages in the container, the administrator must migrate these certificate files manually from the 4.3 installation after the migration.

Procedure: Migrating the Certificates

Copy the file from the 4.3 server to the new server. For example, as /local/ca.file.

Copy the file into the container with:

mgrctl cp /local/ca.file server:/etc/pki/trust/anchors/

After successfully running the mgradm migrate command, the Salt setup on all clients will still point to the old 4.3 server.

To redirect them to the 2025.05 server, it is required to rename the new server at the infrastructure level (DHCP and DNS) to use the same FQDN and IP address as 4.3 server.