Anticlue

ITIL: Release Management Overview

Release management process is about controlling and monitoring the flow of changes into an IT infrastructure. Each update or upgrade of a Configuration Item is referred to as a release.

There are three levels of releases. These levels related to releasing hardware or software into your IT infrastructure. Some may be a single change, others may implement many changes at a time.

• Major - A major release usually introduces new capabilities or functions. Major releases may accumulate all the changes from previous minor releases. Major releases advance the version number by a full increment, for example, from version 5.70 to version 6.
• Minor - Minor releases incorporate a number of fixes for known problems into the baseline, or trusted state, of a item. Minor releases usually increment the version number at the first decimal place. For example, version 6.10 would change to version 6.20.
• Emergency - Emergency releases are quick fixes to repair unexpected problems or temporary measures to prevent the interruption of critical services. Emergency releases increment the version number at the second decimal place, for example, from 3.1 to 3.1.1.

Some releases of new versions of hardware or software introduce incremental changes, while other releases include completely new versions. There are three types of releases to reflect different ways of bundling and deploying changes to hardware or software CIs together. These types are:

1. Delta release - A delta release only includes the elements of a hardware or software CI that have changed. The changes are added to the existing version of the CI. In delta releases, it's not always possible to test how changes will affect the rest of the live environment.
2. Full release - A full release includes all the elements of a hardware or software CI, even those that have not changed. In full releases, the effect of the changes is more carefully tested and less likely to cause incidents during implementation.
3. Package release - A package release rolls the changes to different CIs into a single release. This release may include changes to hardware and software CIs and can contain delta and full releases. Package releases minimize disruptions in the IT environment.

Making changes to an IT infrastructure creates a risk that the changes will have unforeseen results. Careful execution of releases avoids errors and disruptions. There are five steps in the release management process:

• Build and configure - The components of the release are assembled in a controlled laboratory environment.
• Test and accept - Prior to distribution, testing by an independent group occurs. Testers can be business staff, users, or other IT staff. They verify the release using several testing methods; then it can be rolled out.
• Schedule and plan - The rollout of the release must be carefully planned and scheduled. The plan should include a list of all CIs to be added or removed and a schedule of activities at each location involved in the rollout.
• Communicate and prepare - Release management must communicate the rollout plan. Each participant needs to know what preparations to make. Users, managers, and technicians who will implement the release need to know what will happen and when it will happen.
• Distribute and install - When the planned date for installation arrives, the release can be installed according to the prepared plan. Hardware and software must be distributed to the installation site. Installers must follow a prepared script of activities to complete the installation.

Release management stores the master copies of all software applications in a Definitive Software Library (DSL). The library provides a storage facility that keeps master copies of software separate from copies in the live, test, or development environments. The contents of the DSL are recorded in the configuration management database.
Definitive hardware store (DHS)

The Definitive Hardware Store (DHS) is a secure storage location that contains duplicate copies of hardware CIs and assemblies. The CIs are identical to those in use. The spare CIs must be kept ready for use. Any changes to the configuration of CIs in the live environment are also made to the spares in the DHS. If a hardware CI fails, it can be quickly replaced.

A company's information needs change constantly. The available technology changes rapidly. The release management process provides a way to manage change without creating chaos.