Only the api_url key from ConfigMap city-portal should become the PORTAL_URL environment variable. Which configuration is appropriate?
Select an answer to reveal the explanation.
Short Explanation
When one setting needs a new name in the process environment, configMapKeyRef is the adapter cable. Point PORTAL_URL at city-portal’s api_url key. envFrom would pour every key in under their original names.
Full Explanation
valueFrom.configMapKeyRef selects one ConfigMap key and maps it to a chosen environment variable name. envFrom imports all keys using their ConfigMap key names. Secrets use secretKeyRef and are unnecessary for non-sensitive single keys already stored in a ConfigMap. downwardAPI exposes Pod metadata fields, not arbitrary ConfigMap data.