## What’s New (Major Themes)

We’re pleased to announce the delivery of Kubernetes 1.16, our third release of 2019! Kubernetes 1.16 consists of 31 enhancements: 8 enhancements moving to stable, 8 enhancements in beta, and 15 enhancements in alpha.

The main themes of this release are:

## Changelog since v1.26.0-alpha.2

## Changes by Kind

### API Change

- **Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.**:
  
  <!--
  This section can be blank if this pull request does not require a release note.
  
  When adding links which point to resources within git repositories, like

  repeated ConfigMap items = 2;
}

// ConfigMapNodeConfigSource contains the information to reference a ConfigMap as a config source for the Node.
// This API is deprecated since 1.22: https://git.k8s.io/enhancements/keps/sig-node/281-dynamic-kubelet-configuration
message ConfigMapNodeConfigSource {
  // Namespace is the metadata.namespace of the referenced ConfigMap.
  // This field is required in all cases.

Storage promoted the [Kubernetes volume topology feature](https://github.com/kubernetes/enhancements/issues/490) to beta. This enables Kubernetes to understand and act intelligently on volume accessibility information (such as the “zone” a cloud volume is provisioned in, the “rack” that a SAN array is accessible from, and so on).

The [dynamic maximum volume count](https://github.com/kubernetes/enhancements/issues/554) feature was also moved to beta. This enables a volume plugin to specify...

Pod with multiple containers can use `kubectl.kubernetes.io/default-container` annotation to have a container preselected for kubectl commands. More can be read in [KEP-2227](https://github.com/kubernetes/enhancements/blob/master/keps/sig-cli/2227-kubectl-default-container/README.md).

### Immutable Secrets and ConfigMaps

containers](https://kubernetes.io/docs/concepts/workloads/pods/ephemeral-containers/), it became more obvious how we can support developers with tooling built on top of `kubectl exec`. The addition of the `kubectl debug` [command](https://github.com/kubernetes/enhancements/blob/master/keps/sig-cli/1441-kubectl-debug/README.md) (it is alpha but your feedback is more than welcome), allows developers to easily debug their Pods inside the cluster. We think this addition is invaluable.  This command allows one to create...

### `TensorRT`

*   Issues a warning when the `session_config` parameter for the TF1 converter
    is used or the `rewrite_config_template` field in the TF2 converter
    parameter object is used.

### TPU Enhancements:

*   Adds support for the `beta` parameter of the FTRL optimizer for TPU
    embeddings. Users of other TensorFlow platforms can implement equivalent
    behavior by adjusting the `l2` parameter.

- StatefulSet autodelete will respect controlling owners on PVC claims as described in https://github.com/kubernetes/enhancements/pull/4375 ([#126581](https://github.com/kubernetes/kubernetes/pull/126581), [@mattcary](https://github.com/mattcary)) [SIG Apps, Storage and Testing]

- StatefulSet autodelete will respect controlling owners on PVC claims as described in https://github.com/kubernetes/enhancements/pull/4375 ([#125389](https://github.com/kubernetes/kubernetes/pull/125389), [@mattcary](https://github.com/mattcary)) [SIG Apps and Testing]

## Introduction to 1.9.0