---
title: 容器环境
content_type: concept
weight: 20
---
<!--
reviewers:
- mikedanese
- thockin
title: Container Environment
content_type: concept
weight: 20
-->

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<!--
This page describes the resources available to Containers in the Container environment. 
-->
本页描述了在容器环境里容器可用的资源。

<!-- body -->

<!--
## Container environment

The Kubernetes Container environment provides several important resources to Containers:

* A filesystem, which is a combination of an [image](/docs/concepts/containers/images/) and one or more [volumes](/docs/concepts/storage/volumes/).
* Information about the Container itself.
* Information about other objects in the cluster.
-->
## 容器环境  {#container-environment}

Kubernetes 的容器环境给容器提供了几个重要的资源：

* 文件系统，其中包含一个[镜像](/zh/docs/concepts/containers/images/)
  和一个或多个的[卷](/zh/docs/concepts/storage/volumes/)
* 容器自身的信息
* 集群中其他对象的信息

<!--
### Container information

The *hostname* of a Container is the name of the Pod in which the Container is running.
It is available through the `hostname` command or the
[`gethostname`](http://man7.org/linux/man-pages/man2/gethostname.2.html)
function call in libc.

The Pod name and namespace are available as environment variables through the
[downward API](/docs/tasks/inject-data-application/downward-api-volume-expose-pod-information/).

User defined environment variables from the Pod definition are also available to the Container,
as are any environment variables specified statically in the Docker image.
-->
### 容器信息

容器的 *hostname* 是它所运行在的 pod 的名称。它可以通过 `hostname` 命令或者调用 libc 中的
[`gethostname`](https://man7.org/linux/man-pages/man2/gethostname.2.html) 函数来获取。

Pod 名称和命名空间可以通过
[下行 API](/zh/docs/tasks/inject-data-application/downward-api-volume-expose-pod-information/)
转换为环境变量。

Pod 定义中的用户所定义的环境变量也可在容器中使用，就像在 Docker 镜像中静态指定的任何环境变量一样。

<!--
### Cluster information

A list of all services that were running when a Container was created is available to that Container as environment variables.
Those environment variables match the syntax of Docker links.

For a service named *foo* that maps to a Container named *bar*,
the following variables are defined:
-->
### 集群信息

创建容器时正在运行的所有服务的列表都可用作该容器的环境变量。这些环境变量与 Docker 链接的语法匹配。

对于名为 *foo* 的服务，当映射到名为 *bar* 的容器时，以下变量是被定义了的：

```shell
FOO_SERVICE_HOST=<the host the service is running on>
FOO_SERVICE_PORT=<the port the service is running on>
```

<!--
Services have dedicated IP addresses and are available to the Container via DNS,
if [DNS addon](http://releases.k8s.io/{{< param "githubbranch" >}}/cluster/addons/dns/) is enabled. 
-->
服务具有专用的 IP 地址。如果启用了
[DNS插件](https://releases.k8s.io/{{< param "githubbranch" >}}/cluster/addons/dns/)，
可以在容器中通过 DNS 来访问服务。

## {{% heading "whatsnext" %}}

<!--
* Learn more about [Container lifecycle hooks](/docs/concepts/containers/container-lifecycle-hooks/).
* Get hands-on experience
  [attaching handlers to Container lifecycle events](/docs/tasks/configure-pod-container/attach-handler-lifecycle-event/).
-->
* 学习更多有关[容器生命周期回调](/zh/docs/concepts/containers/container-lifecycle-hooks/)的知识
* 动手[为容器生命周期事件添加处理程序](/zh/docs/tasks/configure-pod-container/attach-handler-lifecycle-event/)


