Chapter 2 Spacewalk Concepts

An activation key is a tag that you can associate with a given server configuration, for example, a Database server on an Oracle Linux 7 (x86_64) system. When a client system registers with a Spacewalk server, it specifies an activation key to select the characteristics that are bound to that key, such as which software channels the client should be subscribed to. You can also use activation keys to trigger Spacewalk to install specific packages and deploy a specialized configuration on registration.

Spacewalk client systems subscribe to Spacewalk software channels to obtain software packages and errata. A base or parent channel provides packages for a specific Oracle Linux release and architecture, and this channel can have a number of child channels that provide additional packages. The following example shows a typical base and child channel configuration for the Oracle Linux 7 (x86_64) release that a client might use:

oraclelinux7-x86_64-base
|-- oraclelinux7-x86_64-addons
|-- oraclelinux7-x86_64-ksplice
|-- oraclelinux7-x86_64-optional
|-- oraclelinux7-x86_64-patch
|-- oraclelinux7-x86_64-spacewalk24-client
|-- oraclelinux7-x86_64-uek-r4

In this example, you would synchronize the content of the base and patch channels with ULN and the content for the Spacewalk client channel with the Oracle Linux yum server. You could synchronize the other channels with either ULN or Oracle Linux yum server. Oracle recommends that you populate the channels manually when you first configure them, and subsequently use automated Spacewalk scheduling or cron to synchronize the channels on a daily basis.

An entitlement limits the number of client systems each organization can register to a Spacewalk server. By default, Spacewalk assigns 20,000 entitlements to a Spacewalk server. When you create an organization, you can specify the number of entitlements for that organization out of the 20,000 that are available in total. If necessary, you can use additional Spacewalk servers to provide more entitlements. When you decommission a system by deleting its entry in Spacewalk, any entitlements assigned to the system are automatically released.

You can organize your client systems into groups, which allows you to perform management operations on multiple systems at a time. A client system can be a member of more than one group. Typically, the member systems of a group have the same Linux release, system architecture, and kickstart profile. You could also group systems by function (for example, web, application, or database servers), by physical location, or by responsible administrator.

An organization in Spacewalk provides a useful way to tier or segment your Spacewalk implementation. By defining multiple organizations, you can establish management entities that correspond to different corporate divisions or administrative groups. Organizations provide a way to logically delegate system management responsibilities and allocate entitlements. Depending on organizational trust relationships, organizations can also share system and software entitlements.

Spacewalk usually provisions packages for software channels by using repositories from an upstream source. For Oracle Linux, you can use the repositories that are provided by either the Oracle Linux yum server (https://yum.oracle.com) or the Unbreakable Linux Network (ULN; https://linux.oracle.com). Some repository content, such as update-level specific patch and Ksplice packages, is available from ULN but not from the Oracle Linux yum server, while other repository content, such as the Spacewalk Client and Spacewalk Server packages, is available from the Oracle Linux yum server but not from ULN. Spacewalk provides a ULN plugin that allows it to synchronize Spacewalk repositories with ULN without needing to register the Spacewalk server directly with ULN. Unless you are an experienced Spacewalk administrator, Oracle recommends that you associate only one repository with each channel to obtain upstream packages. Otherwise, the channel attempts to pull packages from multiple sources.