Registering Red Hat Enterprise Linux Clients with CDN

If you are running Red Hat Enterprise Linux clients directly, rather than using SUSE Linux Enterprise Server with Expanded Support, you need to use Red Hat sources to retrieve and update packages. This section contains information about using the Red Hat content delivery network (CDN) to register traditional and Salt clients running Red Hat Enterprise Linux operating systems.

For information about using Red Hat update infrastructure (RHUI) instead, see client-configuration:clients-rh-rhui.adoc.

Red Hat Enterprise Linux clients are based on Red Hat and are unrelated to SUSE Linux Enterprise Server with Expanded Support, RES, or SUSE Linux Enterprise Server. You are responsible for arranging access to Red Hat base media repositories and RHEL installation media, as well as connecting Uyuni Server to the Red Hat content delivery network. You must obtain support from Red Hat for all your RHEL systems. If you do not do this, you might be violating your terms with Red Hat.

Traditional clients are available on Red Hat Enterprise Linux 6 and 7 only. Red Hat Enterprise Linux 8 clients are supported as Salt clients.

Import Entitlements and Certificates

Red Hat clients require a Red Hat certificate authority (CA) and entitlement certificate, and an entitlement key.

Entitlement certificates are embedded with expiration dates, which match the length of the support subscription. To avoid disruption, you need to repeat this process at the end of every support subscription period.

Red Hat supply a subscription manager tool to manage subscription assignments. It runs locally to track installed products and subscriptions. Clients must be registered with the subscription manager to obtain certificates.

Red Hat clients use a URL to replicate repositories. The URL changes depending on where the Red Hat client is registered.

Red Hat clients can be registered in three different ways:

Red Hat content delivery network (CDN) at redhat.com
Red Hat Satellite Server
Red Hat update infrastructure (RHUI) in the cloud

This guide covers clients registered to Red Hat CDN. You must have at least one system registered to the CDN, with an authorized subscription for repository content.

For information about using Red Hat update infrastructure (RHUI) instead, see client-configuration:clients-rh-rhui.adoc.

Satellite certificates for client systems require a Satellite server and subscription. Clients using Satellite certificates are not supported with Uyuni Server.

Red Hat supplies the subscription-manager tool to manage subscription assignments. It runs locally on the client system to track installed products and subscriptions. Register to redhat.com with subscription-manager, then follow this procedure to obtain certificates.

Procedure: Registering Clients to Subscription Manager

On the client system, at the command prompt, register with the subscription manager tool:
```
subscription-manager register
```
Enter your Red Hat Portal username and password when prompted.
Copy your entitlement certificate and key from the client system, to a location that the Uyuni Server can access:
```
cp /etc/pki/entitlement/ /<example>/entitlement/
```
Your entitlement certificate and key both have a file extension of .pem. The key also has key in the filename.
Copy the Red Hat CA Certificate file from the client system, to the same web location as the entitlement certificate and key:
```
cp /etc/rhsm/ca/redhat-uep.pem /example/entitlement
```

To manage repositories on your Red Hat client, you need to import the CA and entitlement certificates to the Uyuni Server. This requires that you perform the import procedure three times, to create three entries: one each for the entitlement certificate, the entitlement key, and the Red Hat certificate.

Procedure: Importing Certificates to the Server

On the Uyuni Server Web UI, navigate to Systems Autoinstallation GPG and SSL Keys.
Click Create Stored Key/Cert and set these parameters for the entitlement certificate:
- In the Description field, type Entitlement-Cert-date.
- In the Type field, select SSL.
- In the Select file to upload field, browse to the location where you saved the entitlement certificate, and select the .pem certificate file.
Click Create Key.
Click Create Stored Key/Cert and set these parameters for the entitlement key:
- In the Description field, type Entitlement-key-date.
- In the Type field, select SSL.
- In the Select file to upload field, browse to the location where you saved the entitlement key, and select the .pem key file.
Click Create Key.
Click Create Stored Key/Cert and set these parameters for the Red Hat certificate:
- In the Description field, type redhat-uep.
- In the Type field, select SSL.
- In the Select file to upload field, browse to the location where you saved the Red Hat certificate, and select the certificate file.
Click Create Key.

Prepare Custom Repositories and Channels

To mirror the software from the Red Hat CDN, you need to create custom channels and repositories in Uyuni that are linked to the CDN by a URL. You must have entitlements to these products in your Red Hat Portal for this to work correctly. You can use the subscription manager tool to get the URLs of the repositories you want to mirror:

subscription-manager repos

You can use these repository URLs to create custom repositories. This allows you to mirror only the content you need to manage your clients.

You can only create custom versions of Red Hat repositories if you have the correct entitlements in your Red Hat Portal.

The details you need for this procedure are:

Table 1. Red Hat Custom Repository Settings
Option	Setting
Repository URL	The content URL provided by Red Hat CDN
Has Signed Metadata?	Uncheck all Red Hat Enterprise repositories
SSL CA Certificate	`redhat-uep`
SSL Client Certificate	`Entitlement-Cert-date`
SSL Client Key	`Entitlement-Key-date`

Procedure: Creating Custom Repositories

On the Uyuni Server Web UI, navigate to Software Manage Repositories.
Click Create Repository and set the appropriate parameters for the main repository.
Click Create Repository.
Repeat for all repositories you need to create.

The channels you need for this procedure are:

Table 2. Red Hat Custom Channels
OS Version	Base Product	Base Channel
Red Hat 6	RHEL6 Base x86_64	rhel6-pool-x86_64
Red Hat 7	RHEL7 Base x86_64	rhel7-pool-x86_64
Red Hat 8	RHEL or SLES ES or CentOS 8 Base	rhel8-pool-x86_64

Procedure: Creating Custom Channels

On the Uyuni Server Web UI, navigate to Software Manage Channels.
Click Create Channel and set the appropriate parameters for the channels.
In the Parent Channel field, select the appropriate base channel.
Click Create Channel.
Repeat for all channels you need to create. There should be one custom channel for each custom repository.

You can check that you have created all the appropriate channels and repositories, by navigating to Software Channel List All.

For Red Hat 8 clients, add both the Base and AppStream channels. You require packages from both channels. If you do not add both channels, you cannot create the bootstrap repository, due to missing packages.

When you have created all the channels, you can associate them with the repositories you created:

Procedure: Associating Channels with Repositories

On the Uyuni Server Web UI, navigate to Software Manage Channels, and click the channel to associate.
Navigate to the Repositories tab, and check the repository to associate with this channel.
Click Update Repositories to associate the channel and the repository.
Repeat for all channels and repositories you need to associate.
OPTIONAL: Navigate to the Sync tab to set a recurring schedule for synchronization of this repository.
Click Sync Now to begin synchronization immediately.

Add Software Channels

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

The channels you need for this procedure are:

Table 3. Red Hat Channels - CLI
OS Version	Base Channel	Client Channel	Tools Channel
Red Hat 6	rhel-x86_64-server-6	-	res6-suse-manager-tools-x86_64
Red Hat 7	rhel-x86_64-server-7	-	res7-suse-manager-tools-x86_64
Red Hat 8	rhel-x86_64-server-8	-	res8-suse-manager-tools-x86_64

Procedure: Adding Software Channels at the Command Prompt

At the command prompt on the Uyuni Server, as root, use the spacewalk-common-channels command to add the appropriate channels:
```
spacewalk-common-channels \
<channel_label_1> \
<channel_label_2> \
<channel_label_3> \
... <channel_label_n>
```
Synchronize the channels:
```
spacewalk-repo-sync
```
Ensure the synchronization is complete before continuing.

The client tools channel provided by spacewalk-common-channels is sourced from Uyuni and not from SUSE.

Check Synchronization Status

Procedure: Checking Synchronization Progress

In the Uyuni Web UI, navigate to Software Manage Channels, then click the channel associated to the repository.
Navigate to the Repositories tab, then click Sync and check Sync Status.

Procedure: Checking Synchronization Progress from the Command Prompt

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
```
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.

Red Hat Enterprise Linux channels can be very large. Synchronization can sometimes take several hours.

Procedure: OPTIONAL: Creating a Salt State to Deploy Configuration Files

On the Uyuni Server Web UI, navigate to Configuration Channels.
Click Create State Channel.
- In the Name field, type subscription-manager: disable yum plugins.
- In the Label field, type subscription-manager-disable-yum-plugins.
- In the Description field, type subscription-manager: disable yum plugins.
- In the SLS Contents field, leave it empty.
Click Create Config Channel
Click Create Configuration File
- In the Filename/Path field type /etc/yum/pluginconf.d/subscription-manager.conf.
- In the File Contents field type:

[main]
enabled=0

Click Create Configuration File
Take note of the value of the field Salt Filesystem Path`.
Click on the name of the Configuration Channel.
Click on View/Edit 'init.sls' File
- In the File Contents field, type:

configure_subscription-manager-disable-yum-plugins:
  cmd.run:
    - name: subscription-manager config --rhsm.auto_enable_yum_plugins=0
    - watch:
      - file: /etc/yum/pluginconf.d/subscription-manager.conf
  file.managed:
    - name: /etc/yum/pluginconf.d/subscription-manager.conf
    - source: salt:///etc/yum/pluginconf.d/subscription-manager.conf

Click Update Configuration File.

The Creating a Salt State to Deploy Configuration Files procedure is optional.

Procedure: Creating a System Group for Red Hat Enterprise Linux Clients

On the Uyuni Server Web UI, navigate to Systems System Groups.
Click Create Group.
- In the Name field, type rhel-systems.
- In the Description field, type All RHEL systems.
Click Create Group.
Click States tab.
Click Configuration Channels tab.
Type subscription-manager: disable yum plugins at the search box.
Click Search to see the state.
Click the checkbox for the state at the Assign column.
Click Save changes.
Click Confirm.

If you already have RHEL systems added to Uyuni, assign them to the new system group, and then apply the highstate.

Procedure: Adding the System Group to Activation Keys

You need to modify the activation keys you used for RHEL systems to include the system group created above.

On the Uyuni Server Web UI, navigate to Systems Activation Keys.
For each the Activation Keys you used for RHEL systems, click on it and:
Navigate to the Groups tab, and the Join subtab.
Check Select rhel-systems.
Click Join Selected Groups.

Trust GPG Keys on Clients

By default, operating systems trust only their own GPG keys when they are installed, and do not trust keys provided by third party packages. The clients can be successfully bootstrapped without the GPG key being trusted. However, you cannot install new client tool packages or update them until the keys are trusted.

Salt clients are set to trust SUSE tools channels GPG keys when they are bootstrapped. For all other clients and channels, you need to manually trust third party GPG keys.

Procedure: Trusting GPG Keys on Clients

On the Uyuni Server, at the command prompt, check the contents of the /srv/www/htdocs/pub/ directory. This directory contains all available public keys. Take a note of the key that applies to the channel assigned to the client you are registering.
Open the relevant bootstrap script, locate the ORG_GPG_KEY= parameter and add the required key. For example:
```
uyuni-gpg-pubkey-0d20833e.key
```
You do not need to delete any previously stored keys.
If you are bootstrapping clients from the Uyuni Web UI, you need to use a Salt state to trust the key. Create the Salt state and assign it to the organization. You can then use an activation key and configuration channels to deploy the key to the clients.

Register Clients

To register your Red Hat 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-configuration:registration-overview.adoc.

To register and use Red Hat Enterprise Linux 6 clients, you need to configure the Uyuni Server to support older types of SSL encryption. For more information about how to resolve this error, see Registering Older Clients at client-configuration:tshoot-clients.adoc.

Package Management and Red Hat Enterprise Linux 8 Clients

If you are using Red Hat Enterprise Linux 8 clients, you cannot perform package operations such as installing or upgrading directly from modular repositories like the Red Hat Enterprise Linux AppStream repository. You can use the AppStream filter with content lifecycle management to transform modular repositories into regular repositories.

For more information about content lifecycle management, see administration:content-lifecycle.adoc.