Satellite Overview, Concepts, and Deployment Considerations

The following diagram represents the high-level architecture of Red Hat Satellite.

Figure 1.1. Red Hat Satellite System Architecture

There are four stages through which content flows in this architecture:

The following diagram provides a closer look at the distribution of content from Satellite Server to Capsules.

Figure 1.2. Content Life Cycle in Red Hat Satellite

By default, each organization has a Library of content from external sources. Content Views are subsets of content from the Library created by intelligent filtering. You can publish and promote Content Views into life cycle environments (typically Dev, QA, and Production). When creating a Capsule Server, you can choose which life cycle environments will be copied to that Capsule and made available to managed hosts.

Content Views can be combined to create Composite Content Views. It can be beneficial to have a separate Content View for a repository of packages required by an operating system and a separate one for a repository of packages required by an application. One advantage is that any updates to packages in one repository only requires republishing the relevant Content View. You can then use Composite Content Views to combine published Content Views for ease of management.

Which Content Views should be promoted to which Capsule Server depends on the Capsule’s intended functionality. Any Capsule Server can run DNS, DHCP, and TFTP as infrastructure services that can be supplemented, for example, with content or configuration services.

You can update Capsule Server by creating a new version of a Content View using synchronized content from the Library. The new Content View version is then promoted through life cycle environments. You can also create in-place updates of Content Views. This means creating a minor version of the Content View in its current life cycle environment without promoting it from the Library. For example, if you need to apply a security erratum to a Content View used in Production, you can update the Content View directly without promoting to other life cycles. For more information on content management, see Managing Content.

Red Hat Satellite consists of several open source projects which are integrated, verified, delivered and supported as Satellite. This information is maintained and regularly updated on the Red Hat Customer Portal; see Satellite 6 Component Versions.

Red Hat Satellite consists of the following open source projects:

The terminology used in Red Hat Satellite and its components is extensive. For explanations of frequently used terms, see Appendix B, Glossary of Terms.

Each Red Hat Satellite subscription includes one supported instance of Red Hat Enterprise Linux Server. This instance should be reserved solely for the purpose of running Red Hat Satellite. Using the operating system included with Satellite to run other daemons, applications, or services within your environment is not supported.

Support for Red Hat Satellite components is described below.

SELinux must be either in enforcing or permissive mode, installation with disabled SELinux is not supported.

There are two sets of features provided by Capsule Servers. You can use Capsule to run services required for host management. You can also configure Capsule to mirror content from Satellite Server.

Infrastructure and host management services:

Content related features:

Not all Capsule features have to be enabled at once. You can configure a Capsule Server for a specific limited purpose. Some common configurations include:

The goal of Capsule isolation is to provide a single endpoint for all of the host’s network communications so that in remote network segments, you need only open firewall ports to the Capsule itself. The following diagram shows how the Satellite components interact in the scenario with hosts connecting to an isolated Capsule.

Figure 2.1. Satellite Topology with Isolated Capsule

The following diagram shows how the Satellite components interact when hosts connect directly to Satellite Server. Note that as the base system of an external Capsule is a Client of the Satellite, this diagram is relevant even if you do not intend to have directly connected hosts.

Figure 2.2. Satellite Topology with Internal Capsule

You can find complete instructions for configuring the host-based firewall to open the required ports in the following documents:

Organizations divide Red Hat Satellite resources into logical groups based on ownership, purpose, content, security level, or other divisions. You can create and manage multiple organizations through Red Hat Satellite, then divide and assign your subscriptions to each individual organization. This provides a method of managing the content of several individual organizations under one management system.

Locations divide organizations into logical groups based on geographical location. Each location is created and used by a single account, although each account can manage multiple locations and organizations.

Application life cycles are divided into life cycle environments which represent each stage of the application life cycle. Life cycle environments are linked to form an environment path. You can promote content along the environment path to the next life cycle environment when required. For example, if development ends on a particular version of an application, you can promote this version to the testing environment and start development on the next version.

Figure 3.2. An Environment Path Containing Four Environments

The fact that host groups can be nested to inherit parameters from each other allows for designing host group hierarchies that fit particular workflows. A well planned host group structure can help to simplify the maintenance of host settings. This section outlines four approaches to organizing host groups.

Figure 4.1. Host Group Structuring Examples

Flat Structure

The advantage of a flat structure is limited complexity, as inheritance is avoided. In a deployment with few host types, this scenario is the best option. However, without inheritance there is a risk of high duplication of settings between host groups.

Life Cycle Environment Based Structure

In this hierarchy, the first host group level is reserved for parameters specific to a life cycle environment. The second level contains operating system related definitions, and the third level contains application specific settings. Such structure is useful in scenarios where responsibilities are divided among life cycle environments (for example, a dedicated owner for the Development, QA, and Production life cycle stages).

Application Based Structure

This hierarchy is based on roles of hosts in a specific application. For example, it enables defining network settings for groups of back-end and front-end servers. The selected characteristics of hosts are segregated, which supports Puppet-focused management of complex configurations. However, the content views can only be assigned to host groups at the bottom level of this hierarchy.

Location Based Structure

In this hierarchy, the distribution of locations is aligned with the host group structure. In a scenario where the location (Capsule Server) topology determines many other attributes, this approach is the best option. On the other hand, this structure complicates sharing parameters across locations, therefore in complex environments with a large number of applications, the number of host group changes required for each configuration change increases significantly.

Preboot execution environment (PXE) provides the ability to boot a system over a network. Instead of using local hard drives or a CD-ROM, PXE uses DHCP to provide host with standard information about the network, to discover a TFTP server, and to download a boot image. For more information about setting up a PXE server see the Red Hat Knowledgebase solution How to set-up/configure a PXE Server.

You can use HTTP booting to boot systems over a network using HTTP.

You can use Kickstart to automate the installation process of a Red Hat Satellite or Capsule Server by creating a Kickstart file that contains all the information that is required for the installation. For more information about Kickstart, see Performing an automated installation using Kickstart in Performing an advanced RHEL 8 installation.

The first step to a working Satellite infrastructure is installing an instance of Satellite Server on a dedicated Red Hat Enterprise Linux 8 server.

Red Hat Satellite requires a single manifest for each organization configured on the Satellite. If you plan to use the Organization feature of Satellite to manage separate units of your infrastructure under one Red Hat Network account, then assign subscriptions from the one account to per-organization manifests as required.

If you plan to have more than one Red Hat Network account, or if you want to manage systems belonging to another entity that is also a Red Hat Network account holder, then you and the other account holder can assign subscriptions, as required, to manifests. A customer that does not have a Satellite subscription can create a Subscription Asset Manager manifest, which can be used with Satellite, if they have other valid subscriptions. You can then use the multiple manifests in one Satellite Server to manage multiple organizations.

If you must manage systems but do not have access to the subscriptions for the RPMs, you must use Red Hat Enterprise Linux Satellite Add-On. For more information, see Satellite Add-On.

The following diagram shows two Red Hat Network account holders, who want their systems to be managed by the same Satellite installation. In this scenario, Example Corporation 1 can allocate any subset of their 60 subscriptions, in this example they have allocated 30, to a manifest. This can be imported into the Satellite as a distinct Organization. This allows system administrators the ability to manage Example Corporation 1’s systems using Satellite completely independently of Example Corporation 2’s organizations (R&D, Operations, and Engineering).

Figure 7.1. Satellite Server with Multiple Manifests

When creating a Red Hat Subscription Manifest:

Red Hat Satellite allows the use of future-dated subscriptions in the manifest. This enables uninterrupted access to repositories when future-dated subscriptions are added to a manifest before the expiry date of existing subscriptions.

Note that the Red Hat Subscription Manifest can be modified and reloaded to Satellite Server in case of any changes in your infrastructure, or when adding more subscriptions. Manifests should not be deleted. If you delete the manifest from the Red Hat Customer Portal or in the Satellite web UI it will unregister all of your content hosts.

When you install Satellite, the satellite-installer command creates databases on the same server that you install Satellite. Depending on your requirements, moving to external databases can provide increased working memory for Satellite, which can improve response times for database operating requests. Moving to external databases distributes the workload and can increase the capacity for performance tuning.

Consider using external databases if you plan to use your Satellite deployment for the following scenarios:

For more information about using an external database, see Using External Databases with Satellite in Installing Satellite Server in a Connected Network Environment.

This section outlines general considerations that should help you to specify your Satellite deployment scenario. The most common deployment scenarios are listed in Chapter 8, Common Deployment Scenarios. The defining questions are:

The Red Hat Subscription Manifest determines what Red Hat repositories are accessible from your Satellite Server. Once you enable a Red Hat repository, an associated Satellite Product is created automatically. For distributing content from custom sources you need to create products and repositories manually. Red Hat repositories are signed with GPG keys by default, and it is recommended to create GPG keys also for your custom repositories. The configuration of custom repositories depends on the type of content they hold (RPM packages, or Docker images).

Repositories configured as yum repositories, that contain only RPM packages, can make use of the new download policy setting to save on synchronization time and storage space. This setting enables selecting from Immediate and On demand. The On demand setting saves space and time by only downloading packages when requested by clients. For detailed instructions on setting up content sources see Importing Content in Managing Content.

A custom repository within Satellite Server is in most cases populated with content from an external staging server. Such servers lie outside of the Satellite infrastructure, however, it is recommended to use a revision control system (such as Git) on these servers to have better control over the custom content.

Satellite provides features for precise management of the content life cycle. A life cycle environment represents a stage in the content life cycle, a Content View is a filtered set of content, and can be considered as a defined subset of content. By associating Content Views with life cycle environments, you make content available to hosts in a defined way. See Figure 1.2, “Content Life Cycle in Red Hat Satellite” for visualization of the process. For a detailed overview of the content management process see Importing Custom Content in Managing Content. The following section provides general scenarios for deploying content views as well as life cycle environments.

The default life cycle environment called Library gathers content from all connected sources. It is not recommended to associate hosts directly with the Library as it prevents any testing of content before making it available to hosts. Instead, create a life cycle environment path that suits your content workflow. The following scenarios are common:

The following content view scenarios are common:

The optimal solution depends on the nature of your host environment. Avoid creating a large number of content views, but keep in mind that the size of a content view affects the speed of related operations (publishing, promoting). Also make sure that when creating a subset of packages for the content view, all dependencies are included as well. Note that kickstart repositories should not be added to content views, as they are used for host provisioning only.

Content deployment is the management of errata and packages on content hosts. There are two methods for content deployment on Satellite. The default method is remote execution, and the second method is the deprecated Katello agent.

Satellite provides several features to help you automate the host provisioning, including provisioning templates, configuration management with Puppet, and host groups for standardized provisioning of host roles. For a description of the provisioning workflow see Provisioning Workflow in Provisioning Hosts. The same guide contains instructions for provisioning on various compute resources.

Assigning a role to a user enables controlling access to Satellite components based on a set of permissions. You can think of role based authentication as a way of hiding unnecessary objects from users who are not supposed to interact with them.

There are various criteria for distinguishing among different roles within an organization. Apart from the administrator role, the following types are common:

When defining a custom role, consider the following recommendations:

For instructions on defining roles and assigning them to users, see Managing Users and Roles in Administering Red Hat Satellite. The same guide contains information on configuring external authentication sources.

This section provides a short overview of selected Satellite capabilities that can be used for automating certain tasks or extending the core usage of Satellite:

An integrated Capsule is a virtual Capsule Server that is created by default in Satellite Server during the installation process. This means Satellite Server can be used to provision directly connected hosts for Satellite deployment in a single geographical location, therefore only one physical server is needed. The base systems of isolated Capsules can be directly managed by Satellite Server, however it is not recommended to use this layout to manage other hosts in remote locations.

Your infrastructure might require multiple isolated subnets even if Red Hat Satellite is deployed in a single geographic location. This can be achieved for example by deploying multiple Capsule Servers with DHCP and DNS services, but the recommended way is to create segregated subnets using a single Capsule. This Capsule is then used to manage hosts and compute resources in those segregated networks to ensure they only have to access the Capsule for provisioning, configuration, errata, and general management. For more information on configuring subnets see Managing Hosts.

It is recommended to create at least one Capsule Server per geographic location. This practice can save bandwidth since hosts obtain content from a local Capsule Server. Synchronization of content from remote repositories is done only by the Capsule, not by each host in a location. In addition, this layout makes the provisioning infrastructure more reliable and easier to configure. See Figure 1.1, “Red Hat Satellite System Architecture” for an illustration of this approach.

In high security environments where hosts are required to function in a closed network disconnected from the Internet, Red Hat Satellite can provision systems with the latest security updates, errata, packages and other content. In such case, Satellite Server does not have direct access to the Internet, but the layout of other infrastructure components is not affected. For information about installing Satellite Server from a disconnected network, see Installing Satellite Server in a Disconnected Network Environment. For information about upgrading a disconnected Satellite, see Upgrading a Disconnected Satellite Server in Upgrading and Updating Red Hat Satellite.

There are two options for importing content to a disconnected Satellite Server:

The above methods for importing content to a disconnected Satellite Server can also be used to speed up the initial population of a connected Satellite.

You can configure a Capsule Server (integrated or standalone) to use external DNS, DHCP, or TFTP service. If you already have a server that provides these services in your environment, you can integrate it with your Satellite deployment. For information about how to configure a Capsule with external services, see Configuring Capsule Server with External Services in Installing Capsule Server.