7.6. Channels

In addition to base channels for major versions of Red Hat Enterprise Linux, there are channels for update versions of Red Hat Enterprise Linux, which are also separated by architecture and which can have child channels. These Extended Update Support (EUS) channels are for administrators who want to stay with one major or update version of Red Hat Enterprise Linux and customize their package updates for their particular version, rather than upgrade their systems to a new update version that installs new software, hardware drivers, and features on production systems.

For example, administrators can standardize their desktop systems to Red Hat Enterprise Linux 5.1 for x86, while managing servers on Red Hat Enterprise Linux 4.5 for AMD64 and EM64T. Administrators can stay on their version for the duration of the EUS support lifecycle, assured of the behavior of their software version. Additionally, administrators can install critical software updates without introducing bugs from untested new features or software.

General information about the channel and the parent channel, if it is a child channel. This is the first tab displayed when you click on a channel. It displays essential information about the channel, such as summary, description, and architecture.

—In addition, a Globally Subscribable checkbox can be seen by Satellite Administrators and Channel Administrators. This signifies the default behavior of every channel allowing any user to subscribe systems to it. Unchecking this box and clicking Update causes the appearance of a Subscribers tab, which may then be used to grant certain users subscription permissions to the channel. Satellite Administrators and Channel Administrators can always subscribe systems to any channel.

— Only customers with custom base channels may change their systems' base channel assignment. They may do this through the website in two ways:

List of Errata affecting the channel. The list displays advisory types, names, summaries, and the dates issued. Clicking on an advisory name takes you to its Errata Details page. Refer to Section 7.5.2.2, “Errata Details” for more information.

List of packages in the channel. To download packages as a .tar file, select them and click the Download Packages button at the bottom-left corner of the page. Clicking on a package name takes you to the Package Details page. This page displays a set of tabs with information about the package, including which architectures it runs on, the package size, build date, package dependencies, the change log, list of files in the package, newer versions, and which systems have the package installed. From here, you can download the packages as RPMs or SRPMs.

To search for a specific package or a subset of packages, use the package filter at the top of the list. Enter a substring to search all packages in the list for package names that contain the string. For example, typing ks in the filter might return: ksconfig, krb5-workstation, and links. The filter is case-insensitive.

List of entitled systems subscribed to the channel. The list displays system names, base channels, and their levels of entitlement. Clicking on a system name takes you to its System Details page. Refer to Section 7.4.2.9, “System Details” for more information.

—If it is a child channel, you also have the option of unsubscribing systems from the channel. Use the checkboxes to select the systems, then click the Unsubscribe button on the bottom right-hand corner.

List of entitled systems that are eligible for subscription to the channel. This tab appears only for child channels. Use the checkboxes to select the systems, then click the Subscribe button on the bottom right-hand corner. You will receive a success message or be notified of any errors. This can also be accomplished through the Channels tab of the System Details page. Refer to Section 7.4.2.9, “System Details” for more information.

This screen lists the selections you made during the channel creation process. This page includes the Globally Subscribable checkbox that permits all users to subscribe to the channel.

This subtab allows you to select which users may alter or delete this channel. Satellite Administrators and Channel Administrators may alter or delete any channel.

To allow a user to alter the channel, select the checkbox next to the user's name and click the Update button. To allow all users to manage the channel, click the Select All button at the bottom of the list followed by the Update button. To remove a user's ability to manage the channel, uncheck the box next to their name and click the Update button.

This subtab allows channel managers to list, remove, clone, and add Errata to their custom channel. Custom channels not cloned from a distribution may not add Errata until there are packages in the channel. Only Errata that match the base architecture of the channel and apply to a package in that channel may be added to the channel. Finally, only cloned or custom Errata may be added to custom channels. Errata may be included in a cloned channel if they are selected during channel creation.

This subtab is similar to the Errata subtab. It allows Channel and Organization Administrators to list, remove, compare, and add packages to the custom channel.

To list all packages in the channel, click the List / Remove Packages link. Check the box to the left of any package you wish to remove, then click the Remove Packages button in the lower right of the page.

To add packages, click the Add Packages link. Choose a channel from which to select packages from the drop-down menu and click the View button to continue. Check the box to the left of any package you wish to add to the channel, then click the Add Packages button in the bottom right of the screen.

To compare packages within the current channel with those of another channel, select the other channel from the drop-down menu and click the Compare button. All packages present in either channel are compared, and the results displayed on the next screen. This information includes the architecture and version of each package.

To make the two channels identical, click the Merge Differences button in the lower right. The following screen allows you to select how conflicts are resolved. Click the Preview Merge button to view the results of the merging without making any changes to the channels. Finally, select those packages that you wish to merge and click the Merge Packages button followed by the Confirm button to perform the merge.