Which Kubernetes version introduced a stable feature to make a ConfigMap immutable?

Which Kubernetes version introduced a stable feature to make a ConfigMap immutable?

• A. Kubernetes 1.21
• B. Kubernetes 1.20
• C. Kubernetes 1.19
• D. Kubernetes 1.18

Answer: (A)

ConfigMap immutability becomes a stable, GA feature in this Kubernetes release. When a ConfigMap is created with immutable: true, its data cannot be updated in place. Any attempt to change the data after creation is rejected by the API server, so to apply a new configuration you must delete and recreate the ConfigMap and then roll the pods that depend on it. This behavior reduces frequent etcd writes and ensures all pods see a stable configuration, which is especially important for large-scale deployments. Earlier releases offered immutability only as an alpha/beta behind feature gates, so they weren’t considered stable for production usage. Hence, Kubernetes 1.21 is the release where this becomes a stable, supported feature.

ConfigMap immutability becomes a stable, GA feature in this Kubernetes release. When a ConfigMap is created with immutable: true, its data cannot be updated in place. Any attempt to change the data after creation is rejected by the API server, so to apply a new configuration you must delete and recreate the ConfigMap and then roll the pods that depend on it. This behavior reduces frequent etcd writes and ensures all pods see a stable configuration, which is especially important for large-scale deployments. Earlier releases offered immutability only as an alpha/beta behind feature gates, so they weren’t considered stable for production usage. Hence, Kubernetes 1.21 is the release where this becomes a stable, supported feature.