<p>
The syntax is specified using a
<a href="https://en.wikipedia.org/wiki/Wirth_syntax_notation">variant</a>
of Extended Backus-Naur Form (EBNF):
</p>

<pre class="grammar">
Syntax      = { Production } .
Production  = production_name "=" [ Expression ] "." .
Expression  = Term { "|" Term } .
Term        = Factor { Factor } .
Factor      = production_name | token [ "…" token ] | Group | Option | Repetition .

com/presentation/d/1QUOsQxfEfHlMq4lPjlK2ewQHsr9peEKymDw5_XwZm8Q/edit?usp=sharing)). Bug fixes across bare metal tooling and production-ready user stories, such as the high availability use cases have been given priority for 1.15.

kubeadm, the cluster lifecycle building block, continues to receive features and stability work required for bootstrapping production clusters efficiently. kubeadm has promoted high availability (HA) capability to beta, allowing users to use the familiar `kubeadm...

### Instrumentation

In v1.9 we focused on improving stability of the components owned by the SIG, including Heapster, Custom Metrics API adapters for Prometheus, and Stackdriver.

  purposes, you can use older kernels, as far back as 5.4, if you set the
  `nftables.skipKernelVersionCheck` option in the kube-proxy config, but this is not
  recommended in production since it may cause problems with other nftables
  users on the system.) ([#124152](https://github.com/kubernetes/kubernetes/pull/124152), [@danwinship](https://github.com/danwinship)) [SIG Network]

## Changelog since v1.10.5

### Action Required

## Changelog since v1.11.0

### Action Required

now always set to "systemd" unless the user is explicit about it. This requires existing machine setups to configure the container runtime to use the "systemd" driver. Documentation on this topic can be found here: https://kubernetes.io/docs/setup/production-environment/container-runtimes/. When upgrading existing clusters / nodes using "kubeadm upgrade" the old cgroupDriver value is preserved, but in 1.22 this change will also apply to "upgrade". For more information on migrating to the "systemd" driver...

- kube-apiserver

  - the `--basic-auth-file` flag and authentication mode is deprecated and will be removed in a future release. It is not recommended for production environments. ([#81152](https://github.com/kubernetes/kubernetes/pull/81152), [@tedyu](https://github.com/tedyu))

  // +optional
  optional string appProtocol = 4;
}

// EndpointSubset is a group of addresses with a common set of ports. The
// expanded set of endpoints is the Cartesian product of Addresses x Ports.
// For example, given:
//
// 	{
// 	  Addresses: [{"ip": "10.10.1.1"}, {"ip": "10.10.2.2"}],
// 	  Ports:     [{"name": "a", "port": 8675}, {"name": "b", "port": 309}]
// 	}
//

- The `gcp` and `azure` auth plugins have been removed from client-go and kubectl. See https://github.com/Azure/kubelogin and https://cloud.google.com/blog/products/containers-kubernetes/kubectl-auth-changes-in-gke ([#110013](https://github.com/kubernetes/kubernetes/pull/110013), [@enj](https://github.com/enj))