Manage application configuration: ConfigMaps for non-sensitive data, Secrets for credentials, environment variable injection, volume mounting, and configuration best practices.

# ConfigMap
kubectl create configmap app-config \
  --from-literal=API_URL=https://api.example.com

# Secret
kubectl create secret generic db-creds \
  --from-literal=username=admin \
  --from-literal=password=secret123

# Use as env vars
env:
- name: API_URL
  valueFrom:
    configMapKeyRef:
      name: app-config
      key: API_URL
- name: DB_PASS
  valueFrom:
    secretKeyRef:
      name: db-creds
      key: password

# Mount as volume
volumes:
- name: config
  configMap:
    name: app-config
- name: secrets
  secret:
    secretName: db-creds