// the triple <key,value,effect> using the matching operator <operator>.
message Toleration {
  // Key is the taint key that the toleration applies to. Empty means match all taint keys.
  // If the key is empty, operator must be Exists; this combination means to match all values and all keys.
  // +optional
  optional string key = 1;

  // Operator represents a key's relationship to the value.

	// type of s is string
	// s == a[i]
	g(i, s)
}

var key string
var val interface{}  // element type of m is assignable to val
m := map[string]int{"mon":0, "tue":1, "wed":2, "thu":3, "fri":4, "sat":5, "sun":6}
for key, val = range m {
	h(key, val)
}
// key == last map key encountered in iteration
// val == map[key]

var ch chan Work = producer()
for w := range ch {
	doWork(w)
}

- kubeadm still generates RSA keys when deploying a node, but also accepts ECDSA
keys if they already exist in the directory specified in the `--cert-dir` option. ([#76390](https://github.com/kubernetes/kubernetes/pull/76390), [@rojkov](https://github.com/rojkov))

    * If you are running E2E tests which require SSH keys and you utilize environment variables to override their location, you may need to modify the environment variable set. On all providers the environment variable override can now be either an absolute path to the key or a relative path (relative to ~/.ssh). Specifically the changes are:
    *  - Created new GCE_SSH_KEY allowing specification of SSH keys for gce, gke, and kubemark.

  - `--service-account-key-file`, set to one or more files containing one or more public keys used to verify tokens.

- Kubeadm: warn but do not error out on missing "ca.key" files for root CA, front-proxy CA and etcd CA, during "kubeadm join --control-plane" if the user has provided all certificates, keys and kubeconfig files which require signing with the given CA keys. ([#94988](https://github.com/kubernetes/kubernetes/pull/94988), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]

- Added apiserver identity to the following metrics: 

- Kubeadm: during execution of the "check expiration" command, treat the etcd CA as external if there is a missing etcd CA key file (etcd/ca.key) and perform the proper validation on certificates signed by the...

* kubectl create secret has a new option --from-env-file that populates a secret from file which follows a key=val format for each line.

show/hide actions based on the end user, and for users to quickly reason about their own permissions.

* [alpha] Building on the 1.7 work to allow encryption of resources such as secrets, a mechanism to store resource encryption keys in external Key Management Systems (KMS) was introduced. This complements the original file-based storage and allows integration with multiple KMS. A Google Cloud KMS plugin was added and will be usable once the Google side of the integration is complete....