Applications and Gears

With an understanding of the background technologies that provide a functionality offered in OpenShift, we need to revisit the notion of applications and gears. When we use command-line client utilities, a web administration console, or IDE integration to create an application, it creates one or many gears for our Application. Remembering that this Gear is a resource container constrained with cgroups and confined by SELinux, we can conceptually think of this as our "slice" of the Operating System; within this slice will be our cartridges. We've covered cartridges previously, but as a reminder, these are effectively the puzzle pieces with which we assemble the platform for our web applications, such as language runtimes, databases, and the plugin functionality. A single OpenShift application can consume multiple OpenShift gears in different scenarios, the most common of which is in the situation of an auto-scaling event. The following diagram demonstrates this relationship...