How can you populate environment variables in a container from a ConfigMap?

How can you populate environment variables in a container from a ConfigMap?

• A. Mount the ConfigMap as a Volume
• B. Use envFrom: ConfigMap
• C. Set environment variables via Pod labels
• D. Use a Secret to populate environment variables

Answer: (B)

Environment variables for a container can be populated from a ConfigMap by using the envFrom field with a ConfigMap reference. This approach takes every key-value pair in the ConfigMap and exposes them as environment variables inside the container, with the keys as variable names and the values as their values. It’s the easiest way to inject multiple config values without listing each one individually. Mounting the ConfigMap as a Volume would expose the data as files on disk rather than environment variables. Pod labels are metadata, not a mechanism for setting environment values. Using a Secret to populate environment variables would work for secrets, but it uses a Secret object rather than a ConfigMap.

Environment variables for a container can be populated from a ConfigMap by using the envFrom field with a ConfigMap reference. This approach takes every key-value pair in the ConfigMap and exposes them as environment variables inside the container, with the keys as variable names and the values as their values. It’s the easiest way to inject multiple config values without listing each one individually.

Mounting the ConfigMap as a Volume would expose the data as files on disk rather than environment variables. Pod labels are metadata, not a mechanism for setting environment values. Using a Secret to populate environment variables would work for secrets, but it uses a Secret object rather than a ConfigMap.