Some vendors of RPM-based Linux distributions also provide utilities that can help with management of the distributions they create. Red Hat has created two complementary products, the Red Hat Network (RHN) and up2date, which together provide much the same functionality for managing Red Hat Linux installations as tools such as AutoUpdate and AutoRPM, as well as offering more advanced features.

Red Hat Network is a subscription-based service offered by Red Hat Red Hat Network makes software available for installation via the network. (A free evaluation is also available.) After registering machines with Red Hat Network, administrators can pull updates or new software for installation to those registered machines. In addition, administrators have access to a Web-based administrative console from which they can view the systems they manage and can push software out to those systems.

Red Hat offers two tiers of access to Red Hat Network. Basic Service subscriptions to Red Hat Network provide the ability to manage single systems. Multiple machines can be subscribed by the same administrator for Basic Service level Red Hat Network access, but they must all be managed independently. The administrator must push out errata to each machine separately. Workgroup Service subscriptions provide the same functionality as Basic Service subscriptions, but they also provide the ability to group multiple machines for simultaneous administration. All errata updates for all machines subscribed to Workgroup Service can be pushed out by a single action, for example. Furthermore, Workgroup Service subscriptions can allow management by multiple administrators if desired, making it possible for large organizations to share responsibilities among administrators.

When using Red Hat Network to manage machines with Workgroup Service subscriptions, Red Hat also offers two optional services: Red Hat Network Proxy Server and Red Hat Network Satellite. The Red Hat Network Proxy Server is, as its name suggests, a proxy server for the Red Hat Network. Using it, errata pushed out via Red Hat Network is downloaded by the organization (only once) to a central server in-house. All machines in that organization subscribed to Red Hat Network get their updated software from that in-house proxy server, significantly reducing the network bandwidth requirements needed to keep large organizations up to date.

In addition, the Red Hat Network Proxy Server can be used to provide all subscribed machines with software not provided with Red Hat Linux. Custom “channels” of supplemental software can be created on the Proxy Server, and machines can be subscribed to those channels as desired. Using this feature, different departments in the organization with different software needs can create independent channels for each department, ensuring that machines get only the software needed on them. Similarly, distinct channels can be created for separate classes of machines, ensuring that servers get only software appropriate for server machines and that desktops only get only software that desktop machines need.

The Red Hat Network is normally centrally administered through Red Hat. Machines subscribed to the Red Hat Network have a system profile on file with Red Hat that details the system’s essential configuration information (what software is installed on it, what CPU architecture it contains, and so forth) needed to determine which software errata are appropriate for that system. Similarly, the Web console through which machines subscribed to Red Hat Network can be administered is also located on a Red Hat server. Customers wishing to use Red Hat Network services, but not wanting the dependency upon Internet access to Red Hat, can create an in-house Red Hat Network by using the Red Hat Network Satellite. This solution is often practical for customers who need to keep system information confidential or for customers whose systems are not able to access the Internet.

Red Hat provides several interfaces for administering machines subscribed to the Red Hat Network. A Web-management console is available at https://rhn.redhat.com/. Administrators of machines subscribed to any level of the Red Hat Network can simply log into this Web site and perform a variety of package-management operations from their Web browsers. In addition to viewing other things, administrators can see what software is currently installed, select and install Red Hat Linux errata or new software, or schedule a time for automatic installation of Red Hat Linux errata.

When using Red Hat Network, rhnsd is a client-side daemon that should be run on subscribed systems. It periodically launches a helper utility, rhn_check, which connects to the Red Hat Network servers and checks for any actions (such as a scheduled installation of errata) that an administrator has selected in the Web console. If any actions have been scheduled for that client machine, rhn_check on the client initiates those actions. By default, rhnsd runs rhn_check every two hours. This time can be increased to check for configuration changes as frequently as every hour if necessary.

In addition, Red Hat provides client-side tools that can be used in a more interactive fashion to connect to the Red Hat Network from subscribed systems. The up2date program provides a graphical and command-line tool that can be used to install packages from Red Hat Network servers. When installing a new package, up2date automatically installs any necessary dependencies the package requires, making it a very convenient tool for adding software to the system. up2date can also be run in update mode, thus telling it to install all updates available for the software already installed on the system. Commonly used options with up2date include those listed in Table 8-4.

Table 8-4Options for the up2date command