Choosing a Deployment Strategy

When planning your CentraSite implementation, you have to select a deployment strategy that supports your organization's SDLC and its implementation requirements. The strategy you select determines the number of stages (instances of a CentraSite registry) that your organization maintains and how it maps the phases of its SDLC to these stages.

When developing Web services and other assets, most IT organizations follow a Systems Development Life Cycle (SDLC) that includes the following basic phases:

Development phase - Web services and other assets are requested and developed, individual contributions are integrated and development tests are conducted.

Test phase - Services and other assets are tested in a controlled environment that simulates production scenarios.

Production phase - Services and other assets are made operational. When an asset reaches this stage, the environment in which it resides is tightly controlled and access to the asset is restricted.

In CentraSite, the steps of a SDLC are represented by a lifecycle model. The lifecycle model is customized for your environment and enables you to establish governance controls over all phases of the SDLC for different types of assets.

There are three basic deployment options. Review the following options and select the strategy that best supports your organization's SDLC and its governance objectives:

Single-Stage Deployment - The entire SDLC is represented within one instance of CentraSite. You deploy and maintain a single registry. The assets you place in the registry remain in the registry over their entire lifecycle.

When you use single-stage strategy, you map all three basic phases of the SDLC to a single lifecycle model in CentraSite. To promote an asset through the SDLC, you switch the asset's lifecycle state in the registry. For example, moving an asset from the development phase to the test phase.

Two-Stage Deployment - In a two-stage deployment, the SDLC is split between two instances of CentraSite. One instance, called the creation CentraSite, is used to manage assets during the development and test phases of the SDLC. The other instance, called the consumption CentraSite, manages assets that are in the production phase of SDLC.

This strategy enables your organization to completely separate assets in the pre-production phases from assets that are actually operational. In some organizations, the physical separation of development and production systems is necessary to satisfy legal regulations.

When you use the two-stage approach, SDLC is represented by two lifecycle models in CentraSite. One lifecycle model exists on the creation CentraSite. This model represents the states that constitute the development and test phases of the SDLC. The other model exists on the consumption CentraSite and represents the states that constitute the production phase of the SDLC.

To promote an asset to a phase of its lifecycle that resides on another stage, you export the asset from its current registry and import it into the registry that hosts the next phase of its lifecycle.

Three-Stage Deployment - In a three-stage deployment, you deploy a separate registry for each major phase of the SDLC: Development, Test, and Production.

Each registry has a lifecycle model that represents the states that constitutes its phase of the SDLC. You can promote an asset from one phase to the next by exporting the asset from its current registry and importing it into the registry that hosts the next phase of the SDLC.

The deployment strategy you select depends on factors such as your organization's policy requirements, standard processes, and governance objectives. Consider the following when selecting a strategy for your organization:

Any deployment that involves multiple stages requires additional effort to configure and administer. The promotion process for a multi-stage environment is more complex and time-consuming as it involves physically exporting objects from one registry and importing them into another. You should not deploy a multi-stage configuration unless there is a compelling reason to do so. Aim for a deployment strategy that aligns well with your organization's SDLC process, satisfies your organization's governance objectives, and uses the fewest number of stages.

If you intend to use CentraSite for both design-time governance and run-time governance, consider using the two-stage deployment. This configuration enables you to maintain one registry for managing Web services (and associated assets) while they are in the development and testing phases of their lifecycle and another registry for configuring, deploying, and monitoring Web services that are in the production phase of their lifecycle.

Although it is possible to use a single-stage deployment for both design-time and run-time governance, such a configuration is suitable only for small or mid-size environments. Do not use a single-stage deployment if you intend to use CentraSite to manage both the design-time and run-time aspects of a large number of assets.

Note:
If you expect your organization's registry to begin small and grow over time, start with a two-stage deployment rather than attempting to switch when you outgrow the single-stage configuration.

If you intend to use CentraSite only for design-time governance, consider using a single-stage deployment. Deploying a multi-stage configuration for design-time governance does not offer any benefits. You should only consider a multi-stage deployment in a design-time implementation, if your organization has a specific need to physically separate the registry of assets in the pre-production phases from the registry of assets in the production phase.