Applications are responsible for bringing together all the components that must be deployed together.
Applications do this task by defining the different versions of each component and defining the different environments that the components must go through on the way to production. In addition, applications also map the constituent hosts and systems (called resources) that a component needs within every environment.
Applications also implement automated deployments, rollbacks, and similar tasks. These tasks are called processes. However, at the application level, processes are concerned only with the components and resources that are necessary for deployment, and related tasks. By contrast, component processes are concerned with running commands and related tasks.).
Applications also introduce snapshots to manage the different versions of each component. A snapshot represents the current state of an application in the environment. Typically, the snapshot is generated in an environment that has no approval gates. This type of environment is called an uncontrolled environment. For most users, the snapshot is pushed through the pipeline.
An environment is a collection of resources that host the application. Environments typically include host systems and IBM UrbanCode Deploy agents. When a deployment is run, it is always done so in an environment. While environments are collections of resources, resources can vary per environment.
For example, environment 1 might include a single web server, a single middleware server, and a single database server. IBM UrbanCode Deploy represents these systems as three separate resources that are running in environment 1. Environment 2, however, might include several clustered databases and servers. To deploy the same components on these different environments, IBM UrbanCode Deploy organizes the resource elements with resource groups. The server also keeps an inventory of everything that is deployed to each environment. In this way, the IBM UrbanCode Deploy server manages the contents of each environment and tracks the differences between those environments.