A “Release Unit” describes the portion of a service or IT infrastructure that is normally released as a single entity according to the organizations release policy. The Release Unit can be thought of as a collection of infrastructure items that when packaged together could perform a useful function. The unit may vary depending on the type or item of service asset or service component. The actual components to be released on a specific occasion may include one or more release units, or may include only part of a release unit. Release Units should contain information about the service, its utilities and warranties and release documentation. These components can be grouped together into a Release Package for a specific release. In general the aim is to decide the most appropriate release unit level for each service asset or component.
A “Release Package” is a set of configuration items that will be built, tested and deployed together as a single release. Each release will take the documented Release Units into account when designing the contents of the Release Package. It may sometimes be necessary to create a Release Package that contains only part of one or more Release Units, but this would only happen in exceptional circumstances. Often there will be different ways of designing Release Packages. Consideration should be given to establishing the most appropriate method for identifiable circumstances, stakeholders and possibilities. Where possible, Release Packages should be designed so that some Release Units can be removed if they cause issues in testing. Releases should be uniquely identified according to a scheme defined in the release policy of your organization.
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