WSUS Concepts

Update

Updates are used for updating or providing a full file replacement for software that is installed on a computer. Every update that is available via WSUS is made of two components: Update files, also referred to as ‘binaries’ and metadata. Update files are the actual files that are installed on a computer. Metadata is the information needed to perform the installation. The information consists of the following:

Category

Categories are used by Windows Update to organize all the updates contained by the system. The following list shows the types of categories available within WSUS:
  • Company
  • Product Family (Top Level Category, TLC)

Company and Product Family are established by update publishers in a hierarchy that reflects product relationships.

All updates must list a Company, Product Family, or Product to indicate what products the update modifies.

Detection logic

Set of rules that determine whether an update is applicable to a computer. These rules tell the MU client (WUA) on the receiving system how to detect whether the product family, SKU or service pack is installed. It ensures that an update is distributed only to the systems that contain the products that are being updated. Detection Logic is also referred to as Update Metadata or Applicability Rules.


Prerequisites

Before an update can be evaluated on the client machine, the client machine must meet a list of conditions, which are called prerequisites. For example, for update A to be evaluated, the client must meet: (Installed OS is XP SP2) AND (file exists with a version stamp in a particular range).

Detectoids, categories and updates could all be used as prerequisites.
For a software bundle, the prerequisite specified for the update will apply to all child packages.


Detectoids

A detectoid contains detection logic to determine if a product/SKU/locale is installed on a computer. Detectoids are most commonly used as prerequisites to updates. Following list shows the types of detectoids:
  • Application locale
  • Architecture
  • Service pack
  • SKU or Feature
  • Windows locale
  • WMI Detection

A detectoid contains detection logic (IsInstalled) to determine , for example, if a product/SKU/locale is installed on a machine.
Detectoids are used as prerequisites to updates. It's the building block for the Detectoid Model.


Supersedence

Supersedence is a relationship between updates, where one update encompasses the functionality of another update and is said to supersede the other update. It allows partners to manage content versions effectively.

Best Practices for authoring supersedence


Update Bundle and Child Packages

An update bundle is one logical update that is comprised of multiple updates. The primary ‘update’ at the top level is called a ‘Parent’ and contains the metadata, classifications and recipients while the lower level individual updates called ‘Child Packages’ contain the binaries and the detection logic. Note: An update bundle can only have one level of child packages under it. The top level parent contains metadata (title, update classification, distribution channel, prerequisites etc); and each child package contains binaries and IsInstalled and IsInstallable logic.
  • Parent Update: The parent update has the metadata such as Title, KB article, Description, Classficiation etc; Prerequisite of the update is usually specified at the parent level, which will apply to each Child package as well.
  • Child package: Each individual child package has the binaries and detection logic of when an update should apply.
    • IsInstalled means "If the following conditions are met, the update is already installed". If this logic evaluates to True, then the update is already in place on the computer and therefore should not be re-offered. Multiple rules are supported to define IsInstalled logic (File rules, registry rules, msi installer rules etc).
    • IsInstallable means "If the following conditions are met, offer the update to the user". This logic is to detect systems on which the update should be installed. Multiple rules are supported to define IsInstallable logic (File rules, registry rules, msi installer rules etc).

The Bundling structure is designed not only to simplify the WSUS admin experience, but also serves the purpose of organizing all of the variations of binaries that represent a particular update:
  • SKUs and Components: Create seperate child packages and bundle them together if your product has seperate binaries for various SKUs and components.
  • Supported Locales: Create seperate child packages and bundle them together if your product has seperate binaries for different locales.
  • Platform support: If your product have seperate 64 bit and 32 bit binaries, create seperate child packages and bundle them together.

Last edited Aug 10, 2009 at 7:01 PM by rhearn, version 4

Comments

No comments yet.