Which two commands create a ConfigMap from a literal key/value and then propagate it to a DeploymentConfig as an environment variable?

Which two commands create a ConfigMap from a literal key/value and then propagate it to a DeploymentConfig as an environment variable?

• A. oc create cm <name> --from-literal <KEY>="<value>"; oc set env dc/<name> --from cm/<name>
• B. oc set env dc/<name> --from cm/<name>; oc create cm <name> --from-literal <KEY>="<value>"
• C. oc create cm <name> --from-literal <KEY>="<value>" ; oc set env dc/<name> --from cm/<name>
• D. oc new cm <name> --from-literal <KEY>="<value>" ; oc set env dc/<name> --from cm/<name>

Answer: (C)

Creating a ConfigMap from a literal and then using that ConfigMap to populate a DeploymentConfig’s environment hinges on doing the two steps in the right order. First, you create the ConfigMap with a literal key/value, which stores that data in Kubernetes. Once the ConfigMap exists, you can wire its contents into the DeploymentConfig by using an env-setting command that pulls from the ConfigMap, pulling all its keys as environment variables with the same names. This is why the sequence is to run the create-configmap command with --from-literal, then run the set-env command on the DeploymentConfig with --from cm/<configmap-name>. Trying to set environment from the ConfigMap before it exists would fail, and using an alternate creation command or order wouldn’t provide the proper, existing source for the environment variables.

Creating a ConfigMap from a literal and then using that ConfigMap to populate a DeploymentConfig’s environment hinges on doing the two steps in the right order. First, you create the ConfigMap with a literal key/value, which stores that data in Kubernetes. Once the ConfigMap exists, you can wire its contents into the DeploymentConfig by using an env-setting command that pulls from the ConfigMap, pulling all its keys as environment variables with the same names. This is why the sequence is to run the create-configmap command with --from-literal, then run the set-env command on the DeploymentConfig with --from cm/. Trying to set environment from the ConfigMap before it exists would fail, and using an alternate creation command or order wouldn’t provide the proper, existing source for the environment variables.