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1.3. Managing Configuration Channels

Red Hat Satellite has features to manage the organization's configuration files. This includes files that are managed centrally in configuration channels and files that are managed locally via individual system profiles. Only a Configuration Administrator or a Satellite Administrator can see these files.
This allows organizations to deploy similar configurations to a group of systems and manage configuration changes centrally.
Centrally-managed files are those that are available to multiple systems; changes to a single file in a central configuration channel can affect many systems. In addition, there are local configuration channels. Each system with a Provisioning entitlement has a local configuration channel (also referred to as an override channel) and a Sandbox channel. Local configuration channels are not created within Red Hat Satellite; local configuration channels automatically exist for each system to which a Provisioning entitlement has been applied.

1.3.1. Preparing Systems for Config Management

For a system to have its configuration managed through Satellite, it must have the appropriate tools and the config-enable file installed. These tools may already be installed on the system, especially if the system was kickstarted with configuration management functionality. If not, they can be found within the Red Hat Network Tools child channel. The following packages should be downloaded and installed:
  • rhncfg - The base libraries and functions needed by all rhncfg-* packages.
  • rhncfg-actions - The code required to run configuration actions scheduled via the Red Hat Network website.
  • rhncfg-client - A command line interface to the client features of the Red Hat Network Configuration Management system.
  • rhncfg-management - A command line interface used to manage Red Hat Network configuration.

1.3.2. Creating a New Configuration Channel

A configuration channel has to be created to house the configuration files that will be deployed to specific systems. To create a new configuration channel:
  1. Log in as a Channel Administrator or an Organization Administrator.
  2. Click the Configuration tab.
  3. On the right-hand frame marked as Configuration Actions, click Create a New Configuration Channel.
  4. Fill in the following fields:
    • Name
    • Label. This field must contain only alphanumeric characters, "-", "_", and "."
    • Description. You must enter a description. This field can contain any brief information that allows you to distinguish this channel from others.
  5. Click Create Config Channel.

1.3.3. Adding Configuration Files to the Configuration Channel

  1. Log in as a Channel Administrator or an Organization Administrator.
  2. Click the Configuration tab.
  3. On the submenu on the left, click on Configuration Channels.
  4. Select the configuration channel the configuration files will be added to.
  5. Click on the subtab Add Files.
  6. Fill in the required fields:
    • File to Upload - the maximum allowed file size for configuration files is 128kb.
    • Filename/Path - the path in the target system the configuration file should be deployed to.
    • Ownership - the user and group that owns the file. If the user and group added in the fields do not exist on the systems where the file is being deployed to, the deployment will fail.
    • File Permissions Mode - permissions on the file based on who can modify it. For example, '644' for text files and '755' for directories and executables will allow global access or execution (but not modification).
    • SELinux context - enter SELinux context like: user_u:role_r:type_t:s0-s15:c0.c1024.
    • Macro Delimiters - a listing of available macros are in the next section, Section 1.3.4, “Including Macros in Configuration Files”

1.3.4. Including Macros in Configuration Files

In traditional file management, you would be required to upload and distribute each file separately, even if the distinction is nominal and the number of variations is in the hundreds or thousands. Red Hat Satellite addresses this by allowing the inclusion of macros, or variables, within the configuration files it manages for Provisioning-entitled systems. In addition to variables for custom system information, the following standard macros are supported:
  • rhn.system.sid
  • rhn.system.profile_name
  • rhn.system.description
  • rhn.system.hostname
  • rhn.system.ip_address
  • rhn.system.custom_info(key_name)
  • rhn.system.net_interface.ip_address(eth_device)
  • rhn.system.net_interface.netmask(eth_device)
  • rhn.system.net_interface.broadcast(eth_device)
  • rhn.system.net_interface.hardware_address(eth_device)
  • rhn.system.net_interface.driver_module(eth_device)
To use this feature, either upload or create a configuration file through the Configuration Channel Details page. Then, open its Configuration File Details page and include the supported macros of your choosing. Ensure that the delimiters used to offset your variables match those set in the Macro Start Delimiter and Macro End Delimiter fields and do not conflict with other characters in the file. We recommend that the delimiters be two characters in length and must not contain the percent (%) symbol.
As an example, you may have a file applicable to all of your servers that differs only in IP address and hostname. Rather than manage a separate configuration file for each server, you may create a single file, such as server.conf, with the IP address and hostname macros included, like so: 
hostname={| rhn.system.hostname |}
ip_address={| rhn.system.net_interface.ip_address(eth0) |}
Upon delivery of the file to individual systems, whether through a scheduled action in the Red Hat Network website or at the command line with the Red Hat Network Configuration Client (rhncfg-client), the variables will be replaced with the hostname and IP address of the system, as recorded in the Satellite's System Profile. In the above configuration file, for example, the deployed version resembles the following: 
hostname=test.example.domain.com
ip_address=177.18.54.7
To capture custom system information, insert the key label into the custom information macro (rhn.system.custom_info). For instance, if you developed a key labeled "asset" you can add it to the custom information macro in a configuration file to have the value substituted on any system containing it. The macro would look like this: 
asset={@ rhn.system.custom_info(asset) @}
Upon deployment of the file to a system containing a value for that key, the macro gets translated, resulting in a string similar to the following: 
asset=Example#456
To include a default value, for instance if one is required to prevent errors, you can append it to the custom information macro, like so: 
asset={@ rhn.system.custom_info(asset) = 'Asset #' @}
This default is overridden by the value on any system containing it.
Using the Red Hat Network Configuration Manager (rhncfg-manager) will not translate or alter the files, as that tool is system agnostic. rhncfg-manager does not depend on system settings.

Note

This features only inserts macros into text files. Binary files cannot be interpolated.

1.3.5. Subscribing Systems to the Configuration Channel

In order for Red Hat Satellite to centrally manage configuration channels through the configuration channels, two requirements must be fulfilled:
To subscribe a system to the configuration channel:
  1. Click Configuration. On the left-hand submenu, click Configuration Channels.
  2. Select the configuration channel where the systems should be added.
  3. On the channel page, click on the Systems → Target Systems subtab.
  4. Select systems to be added to the configuration channel and click Subscribe Systems.

1.3.6. Enabling Configuration Management on Systems

The following requirements need to be met before configuration management can be enabled on systems:
  • Target systems need a provisioning entitlement. See the Systems chapter for the procedure on how to add a provisioning entitlement to a system.
  • A subscription to the Red Hat Satellite Tools channel. See the Systems chapter for the procedure on how to change a child channel.
  1. Log in as Channel Administrator or Satellite Administrator.
  2. Click on Configuration.
  3. On the right-hand frame marked as Configuration Actions, click Enable Configuration Management on Systems.
  4. Select systems to enable.
  5. Schedule the package installation of the rhcfg-* packages. Select a time for these configuration packages to be installed.
  6. Click Enable Red Hat Satellite Configuration Management.
  7. Open a terminal console on the individual systems or remotely login as root. The following actions need to be performed:
    1. Run this command to complete the pending rhncfg-* package installation: 
      # rhn_check
    2. Run the following command to enable Red Hat Network actions: 
      # rhn-actions-control --enable-all