Configuration structures and the selection of configuration items

The configuration model should describe the relationship and position of CIs in each structure. There should be service configuration structure s that identify all the components in a particular service (e.g. the retail service).

An important part of Configuration Management is deciding the level at which control is to be exercised, with top-level CIs broken down into components which are themselves CIs, and so on.

CIs should be selected by applying a top down approach, considering if it is sensible to break down a CI into component CIs. A CI can exist as part of any number of different CIs or CI groups at the same time. For instance, a database product may be used by many application s. Usage links to re-usable and common components of the service should be defined – for instance, a configuration structure for a retail service will use infrastructure CIs such as server s, network and software CIs. The ability to have multiple views through different configuration structures improves accessibility, impact analysis and reporting.

Configuration Management of work products and service components from the service lifecycle may be performed at several levels of granularity. The items placed under Configuration Management will typically include service bundles, service package s, service components, release packages and products that are delivered to the customer, designated internal work products, acquired services, products, tools, system s and other items that are used in creating and describing the configurations required to design, transition and operate the service.

Figure 4.11 (a) Example configuration breakdown for an end-user computing service

Figure 4.11 (b) Example configuration breakdown for a Managed Virtual System

Figure 4.11(a) and (b) gives an example in schematic representation of how a CI structure for an end- user computing service and a Managed Virtual System might be broken down.

Choosing the right CI level is a matter of achieving a balance between information availability, the right level of control, and the resource s and effort needed to support it. Information at a low CI level may not be valuable – for example, although a keyboard is usually exchanged independently, the organization sees it as a consumable, so does not store data about it. CI information is valuable only if it facilitates the management of change, the control of incident s and problem s, or the control of asset s that can be independently moved, copied or changed.

Дата добавления: 2015-10-29