Issue #10 August 2005

What is Red Hat Network?

Red Hat® Network is the system management platform from Red Hat designed to provide complete life cycle management. It provides simple tools to efficiently manage systems on your network, including provisioning new systems, managing their updates and configuration changes, monitoring system performance, and eventually re-deploying the systems for a new purpose.

RHN web interface
Figure 1. Red Hat Network web interface

Why use Red Hat Network?

Red Hat Network is a tool that lowers the overall TCO costs of Linux systems. With Red Hat Network, you are able to improve productivity and lower costs in a way that makes Linux deployable, scalable, manageable, and consistent:

Deployable
Provision new systems remotely according to profiles you create. In just a few minutes, you can deploy hundreds of fully configured Red Hat® Enterprise Linux® systems.
Scalable
Red Hat Network scales to manage 2 or 20,000 systems. Managing groups of systems is just as easy as managing a single system.
Manageable
Red Hat Network uses an intuitive web-based interface to perform management actions. Senior-level Linux administrators aren't required for routine management tasks, freeing up their time for higher value projects.
Consistent
Red Hat Network makes it easy to manage systems consistently, so you know you have the same patches, configurations, monitoring probes or applications on all the systems in a group. Its repeatable processes enables measurability, uniformity, and compliance. And, Red Hat Network can be used as a single tool for managing both Red Hat Enterprise Linux and Solaris environments.

What are the components of Red Hat Network?

As a Red Hat Enterprise Linux user, you receive access to Red Hat Network as a part of your subscription. With access to the Update Module, you can download updates for a system. Additional Red Hat Network services are available as a series of modules that greatly enhance your ability to easily deploy and manage your environment. By using a modular architecture, you can choose the pieces that best fit your needs. The current modules for Red Hat Network are:

  • Update
  • Management
  • Provisioning
  • Monitoring

Red Hat Network also provides options for how to deploy the solution. Red Hat offers a hosted service that helps small deployments get up and running quickly as well as a Satellite Server offering that is built for enterprise deployments.

Modules

Let's examine these pieces of Red Hat Network in more detail.

Note:
For a quick comparison of RHN modules, refer to redhat.com.

Update Module

The Update Module is included with every subscription to Red Hat Enterprise Linux. With Update, you have easy access to security, bug fix, and software enhancement updates directly from Red Hat. An example of a security advisory is shown in Figure 2. Example of a security advisory.

Errata detail example
Figure 2. Example of a security advisory
Content access
Use Red Hat Network to download new updates and security fixes for Red Hat Enterprise Linux as well as new versions of the operating system. This content is digitally signed by Red Hat and delivered over SSL for maximum security.
Package management
Add and remove packages for your systems through the Red Hat Network interface. Red Hat Network also handles all the complexities of dependency checking, making sure you receive all the correct versions of packages required to update an application.
Automatic updates
If you wish, you can set your systems to be automatically updated when updates are available.

Management Module

The Management Module is intended to allow you to scale out to much larger deployments. This is the key functionality that allows administrators to increase their productivity by managing groups of systems at a time.

System grouping
Create groups of systems that you want to manage collectively. You can use this to consistently apply management actions like patching so you don't need to worry about whether that last web server received the latest security fix.
Administrator roles
A security model in Red Hat Network allows you to establish least-privilege responsibilities to administrators. Select the systems or system groups you want someone to manage and even choose the roles you want to administrator to perform.
Scheduling
Scheduled updates allow you to deploy changes to your systems in accordance with your business needs and maintenance window policy. Decide what changes you want to make and then decide you want to roll them out. When the system checks during a maintenance window, it will pick up those updates and deploy them.
Search
Advanced search allows you to compare systems or query the database of information on your systems. For instance, you can query for a given package profile or a specific version of a package or you can query for a given hardware interface on a system. When you've come up with a list of systems that have that interface, you can then choose to take actions on those systems.

Provisioning Module

The Provisioning Module allows you to address the complete life cycle of your systems. Deploy the systems initially through Kickstart by creating a Kickstart profile as shown in Figure 3. Creating a Kickstart profile, manage the configuration file profiles across your systems, and move forward and backward through your changes using snapshots and rollback.

Kickstart profile
Figure 3. Creating a Kickstart profile
Bare metal provisioning
Using Kickstart with PXE booting, you can provision new machines as they come into your environment. Within Red Hat Network, you can create new Kickstart profiles or generate ones based on existing systems. These profiles can be configured to include the exact packages and versions you want to install, allowing you to save profiles that are your "gold standard" version of the operating system, which are deployed to new systems.
Existing state provisioning
You can also use Kickstart profiles to re-deploy a system for a new use with Red Hat Network. This can be very helpful in maximizing hardware resources. In a matter of minutes, you can have servers redeployed for a different use.
Configuration management
Configuration files can be stored in Red Hat Network and deployed centrally. This can be combined with provisioning actions to deploy a fully configured system. It also allows you to put processes in place for ensuring the consistency of configurations across your environment.
Remote commands
You can issue remote commands to managed systems. This can also be added to provisioning actions to include pre- or post-provisioning commands, which can be used to start up any applications that were installed.
Rollback
The Provisioning Module also lets you create snapshots of your systems, including package versions and configuration files as shown in Figure 4. System snapshot. If you make unwanted changes to your systems, you can roll them back to known good states.
System snapshot
Figure 4. System snapshot

Monitoring Module

The Monitoring module provides the ability to measure performance.

Probes
Monitoring probes can be either of a system-level probe, for instance, measuring the system load of the amount of disk space available; a service level probe, which would be actually making a connection to, say, the HTTP port; or additionally, an application-level probe. Application-level probes are available for applications such as Oracle® Database or Apache
Probe suites
To scale monitoring activities, probe suites can be used to group probes into a suite and deploy them to many systems at once. That is a powerful, time-saving tool if you want to collect common metrics across your systems.
Notifications
Each probe has a warning and critical threshold that can be set. When these thresholds are reached, email or pager alerts can be sent to the proper administrators.
Reports
Red Hat Network includes the ability to create graphs to show the performance of probes over time. Additionally, the data collected can be extracted for use in other analysis tools.

Architecture components

In addition to the RHN Modules, three architectures are available to enhance the functionality of your module:

  • Hosted
  • Satellite Server
  • Proxy Server
Note:
For a quick comparison of RHN architectures, refer to redhat.com.

Hosted

The default architecture for using Red Hat Network is the Hosted model as shown in Figure 5. Red Hat Network Hosted architecture. With the Hosted model, all content and system information is kept on Red Hat servers. Each of your systems connect across the Internet to these Red Hat Network servers for all management actions. This allows you to deploy quickly, as the client software is included with every Red Hat Enterprise Linux system and is automatically configured to connect to the Hosted Red Hat Network.

Hosted model
Figure 5. Red Hat Network Hosted architecture

Satellite Server

With the Satellite deployment model, customers are able to really maximize the value of their Red Hat Enterprise Linux deployment. All of the content and system information is stored on the Red Hat Network Satellite server in your network as shown in Figure 6. Red Hat Network Satellite architecture. The Satellite synchronizes with Red Hat Network server to receive new content. All information for the managed systems is stored locally on the Satellite, rather than across the Internet.

Satellite model
Figure 6. Red Hat Network Satellite architecture

With Satellite, customers are able to adapt the system most accurately to meet their business needs. Satellite also provides significant capabilities through APIs. Some of our customers today are using the API layer to build very complex functionality and reporting around Satellite and adapt it very precisely to their business needs. In terms of content, Red Hat Network Satellite provides you with the ability to control content flowing from Red Hat through our cloning functionalities as well as to push in content on a custom basis, which would include not only your in-house applications but also third-party applications and libraries that are used with Red Hat Enterprise Linux.

Proxy Server

Red Hat Network Proxy is an add-on component for either the Hosted or Satellite deployment model. The Proxy acts as a content caching device. In the Hosted environment, this helps cut down on the use of Internet bandwidth, so the same package doesn't get downloaded by every one of your systems. You can also use Proxy with a Satellite, where the Satellite is in one data center and Proxy servers are installed in remote data centers to speed up downloads and increase scalability.

Summary

With Red Hat Network, you have the tools you need to manage the life cycle of your Red Hat Enterprise Linux systems in a way that is deployable, scalable, manageable, and consistent. To learn more about using Red Hat Network, view the the following resources:

About the author

Scott Gilbertson is the Product Marketing Manager for Red Hat Network.