using these rules.
</p>


<h3 id="Identifiers">Identifiers</h3>

<p>
Identifiers name program entities such as variables and types.
An identifier is a sequence of one or more letters and digits.
The first character in an identifier must be a letter.
</p>
<pre class="ebnf">
identifier = letter { letter | unicode_digit } .
</pre>
<pre>
a
_x9

}

// PodResourceClaim references exactly one ResourceClaim through a ClaimSource.
// It adds a name to it that uniquely identifies the ResourceClaim inside the Pod.
// Containers that need access to the ResourceClaim reference it with this name.
message PodResourceClaim {
  // Name uniquely identifies this resource claim inside the pod.
  // This must be a DNS_LABEL.
  optional string name = 1;

* [stable] You can now customize the iSCSI initiator name per volume in the iSCSI volume plugin.

* [stable] You can now specify the World Wide Identifier (WWID) for the volume identifier in the Fibre Channel volume plugin.

* [beta] Reclaim policy in StorageClass

## Introduction to 1.9.0

Kubernetes version 1.9 includes new features and enhancements, as well as fixes to identified issues. The release notes contain a brief overview of the important changes introduced in this release. The content is organized by Special Interest Group ([SIG](https://github.com/kubernetes/community/blob/master/sig-list.md)).

- CEL CRD validation expressions may now reference existing object state using the identifier `oldSelf`. ([#108073](https://github.com/kubernetes/kubernetes/pull/108073), [@benluddy](https://github.com/benluddy))

- Updated an audit annotation key used by the `…/serviceaccounts/<name>/token` resource handler.
  The annotation used to persist the issued credential identifier is now `authentication.kubernetes.io/issued-credential-id`. ([#123098](https://github.com/kubernetes/kubernetes/pull/123098), [@munnerz](https://github.com/munnerz)) [SIG Auth]

## Non-user-facing Changes

* CRI now uses moutpoint as image filesystem identifier instead of UUID. ([#59475](https://github.com/kubernetes/kubernetes/pull/59475), [@Random-Liu](https://github.com/Random-Liu))

* You must now specify `Node.Spec.ConfigSource.ConfigMap.KubeletConfigKey` when using dynamic Kubelet config to tell the Kubelet which key of the `ConfigMap` identifies its config file. ([#59847](https://github.com/kubernetes/kubernetes/pull/59847), [@mtaufen](https://github.com/mtaufen))

  - Improve tests to work better with constrained resources
  - Add support for node auto-discovery
  - Add support for `--cloud-config`
  - Update group identifier to use for Cluster API annotations
  
  ### Exoscale
  - Add support for Exoscale
  
  ### GCE
  - Decrease the number of GCE Read Requests made while deleting nodes

    * no shared pid namespace support
  * Docker version 1.11.2 known issues
    * Kernel crash with Aufs storage driver on Debian Jessie ([#27885](https://github.com/kubernetes/kubernetes/issues/27885))
      which can be identified by the [node problem detector](http://kubernetes.io/docs/admin/node-problem/)
    * Leaked File descriptors ([#275](https://github.com/docker/containerd/issues/275))