OpenShift application components
Component |
oc command |
Description |
---|---|---|
Build config | oc get bc | Information to build an application, including the build method and source code. Manages the application build process, including build pods that create the finished application. |
Deployment config | oc get dc | Information to deploy an application after it’s built. Contains information about environment variables, secrets, upgrade methodology, and persistent storage needs, along with the base image to be used and history of previous deployments. |
Image stream | oc get is | Tracks changes to base images for an application. When a change is detected, it can trigger a new build and deploy the new version of the application using the upgrade method defined in the deployment config. |
Deployment | oc get deployment | A deployed version of an application, built using a unique base image created by the application’s build config. Deployments are tracked by the deployment config, allowing for easy application rollbacks and blue/green upgrades. |
Pod | oc get pod | The container where the application runs. A pod is the scalable application unit in OpenShift. The containers are currently built and managed by docker. |
Replication controller | oc get rc | All pods running the same applications. Replication controllers are used to scale the number of pods for an application up and down as needed. The replication controller is managed by the deployment config and can be scaled manually or automatically using OpenShift. |
Service | oc get service | A single IP address used to interact with all pods in a replication controller. Services are heavily used when interacting between services with the DNS service discovery built into OpenShift. |
Image | oc get image | Container base image, used to deploy pods to serve applications. OpenShift has an internal registry to maintain and serve images. |
Route | oc get route | A route maps a web URL to a deployed application. Routes are maintained in a routing layer that’s integrated into OpenShift and deployed by default. The URLs can be a specified domain and can also be created automatically using a default wildcard domain configured when deploying OpenShift. |