A ConfigMap stores small configuration values as key-value pairs or text blocks. By itself it has no effect; a Pod specification must reference it to provide configuration to a container. section 15.4
Use ConfigMaps to deliver configuration in two practical forms:
- Load keys such as DIAMOL_EDITION into container environment variables. section 15.4
- Mount text blocks such as JSON, YAML, XML, or TOML as files in a container. section 15.4
Inspect injected configuration
Apply a Deployment that references the ConfigMap, inspect the resource with `kubectl describe configmap sleep-config-env`, then verify container variables with `kubectl exec deploy/sleep -- printenv`. For file-based configuration, list `/app/config` and print `config.json` from the container.
