Which command applies a ConfigMap as environment variables to a DeploymentConfig?

Which command applies a ConfigMap as environment variables to a DeploymentConfig?

• A. oc set env dc/<name> --from cm/<name>
• B. oc env set dc/<name> --from cm/<name>
• C. oc set-env dc/<name> --from cm/<name>
• D. oc set env cm/<name> --from dc/<name>

Answer: (A)

Injecting environment variables from a ConfigMap into a DeploymentConfig is done by updating the DeploymentConfig’s environment with the set env command and using the ConfigMap as the source. The correct approach is to run a command that targets the DeploymentConfig and references the ConfigMap with --from. For example, oc set env dc/<name> --from cm/<name>. This tells OpenShift to take every key/value pair in the ConfigMap and expose them as environment variables in the DeploymentConfig’s pods. This works because the set env operation is designed to modify a resource’s environment, and --from cm/<name> is the standard way to pull a ConfigMap’s data into the environment of the target resource. The other forms don’t fit: the syntax with oc env set is not the correct command structure, oc set-env is not the proper command, and pointing from a DeploymentConfig to a ConfigMap or referencing resources in the opposite direction would apply the data to the wrong resource (or not at all). After applying the change, a rollout will recreate pods so the new environment variables are picked up by the containers.

Injecting environment variables from a ConfigMap into a DeploymentConfig is done by updating the DeploymentConfig’s environment with the set env command and using the ConfigMap as the source. The correct approach is to run a command that targets the DeploymentConfig and references the ConfigMap with --from. For example, oc set env dc/ --from cm/. This tells OpenShift to take every key/value pair in the ConfigMap and expose them as environment variables in the DeploymentConfig’s pods.

This works because the set env operation is designed to modify a resource’s environment, and --from cm/ is the standard way to pull a ConfigMap’s data into the environment of the target resource. The other forms don’t fit: the syntax with oc env set is not the correct command structure, oc set-env is not the proper command, and pointing from a DeploymentConfig to a ConfigMap or referencing resources in the opposite direction would apply the data to the wrong resource (or not at all). After applying the change, a rollout will recreate pods so the new environment variables are picked up by the containers.