# Application

OpenShift v3 uses the term "application" as a concept that links services together. You can have as many components as you desire, contained and flexibly linked within a

[project](https://docs.openshift.com/online/architecture/core_concepts/projects_and_users.html#projects)

, and, optionally, labeled to provide grouping or structure. This updated model allows for a standalone MySQL instance, or one shared between JBoss components.

**Dependencies**

OpenShift v3 uses a declarative model where[pods](https://docs.openshift.com/online/architecture/core_concepts/pods_and_services.html#pods)bring themselves in line with a predefined state. Explicit dependencies that are applied are done at runtime rather than just install time ordering.

For example, you might require another service to be available before you start. Such a dependency check is always applicable and not just when you create the two components. Thus, pushing dependency checks into runtime enables the system to stay healthy over time.

Collection

[images](https://docs.openshift.com/online/architecture/core_concepts/containers_and_images.html#docker-images) in OpenShift v3 are mapped 1:1 with [containers](https://docs.openshift.com/online/architecture/core_concepts/containers_and_images.html#containers), which use [pods](https://docs.openshift.com/online/architecture/core_concepts/pods_and_services.html#pods) as their colocation mechanism.
