---
title: 在 Pod 中的容器之间共享进程命名空间
min-kubernetes-server-version: v1.10
content_type: task
weight: 160
---
<!--
---
title: Share Process Namespace between Containers in a Pod
min-kubernetes-server-version: v1.10
reviewers:
- verb
- yujuhong
- dchen1107
content_type: task
weight: 160
---
-->

<!-- overview -->

{{< feature-state state="stable" for_k8s_version="v1.17" >}}

<!--
This page shows how to configure process namespace sharing for a pod. When
process namespace sharing is enabled, processes in a container are visible
to all other containers in that pod.
-->
此页面展示如何为 pod 配置进程命名空间共享。
当启用进程命名空间共享时，容器中的进程对该 pod 中的所有其他容器都是可见的。

<!--
You can use this feature to configure cooperating containers, such as a log
handler sidecar container, or to troubleshoot container images that don't
include debugging utilities like a shell.
-->
您可以使用此功能来配置协作容器，比如日志处理 sidecar 容器，或者对那些不包含诸如 shell 等调试实用工具的镜像进行故障排查。



## {{% heading "prerequisites" %}}


{{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}



<!-- steps -->

<!--
## Configure a Pod
-->
## 配置 Pod

<!--
Process Namespace Sharing is enabled using the `ShareProcessNamespace` field of
`v1.PodSpec`. For example:
-->
进程命名空间共享使用 `v1.PodSpec` 中的 `ShareProcessNamespace` 字段启用。例如：

{{< codenew file="pods/share-process-namespace.yaml" >}}

<!--
1. Create the pod `nginx` on your cluster:

    ```shell
    kubectl apply -f https://k8s.io/examples/pods/share-process-namespace.yaml
    ```

1. Attach to the `shell` container and run `ps`:

    ```shell
    kubectl attach -it nginx -c shell
    ```

    If you don't see a command prompt, try pressing enter.

    ```
    / # ps ax
    PID   USER     TIME  COMMAND
        1 root      0:00 /pause
        8 root      0:00 nginx: master process nginx -g daemon off;
       14 101       0:00 nginx: worker process
       15 root      0:00 sh
       21 root      0:00 ps ax
    ```
-->
1. 在集群中创建 `nginx` pod：

    ```shell
    kubectl apply -f https://k8s.io/examples/pods/share-process-namespace.yaml
    ```
1. 获取容器 `shell`，执行 `ps`：

    ```shell
    kubectl attach -it nginx -c shell
    ```
    如果没有看到命令提示符，请按 enter 回车键。

    ```
    / # ps ax
    PID   USER     TIME  COMMAND
        1 root      0:00 /pause
        8 root      0:00 nginx: master process nginx -g daemon off;
       14 101       0:00 nginx: worker process
       15 root      0:00 sh
       21 root      0:00 ps ax
    ```
<!--
You can signal processes in other containers. For example, send `SIGHUP` to
nginx to restart the worker process. This requires the `SYS_PTRACE` capability.
-->
您可以在其他容器中对进程发出信号。例如，发送 `SIGHUP` 到 nginx 以重启工作进程。这需要 `SYS_PTRACE` 功能。

```
/ # kill -HUP 8
/ # ps ax
PID   USER     TIME  COMMAND
    1 root      0:00 /pause
    8 root      0:00 nginx: master process nginx -g daemon off;
   15 root      0:00 sh
   22 101       0:00 nginx: worker process
   23 root      0:00 ps ax
```

<!--
It's even possible to access another container image using the
`/proc/$pid/root` link.
-->
甚至可以使用 `/proc/$pid/root` 链接访问另一个容器镜像。

```
/ # head /proc/8/root/etc/nginx/nginx.conf

user  nginx;
worker_processes  1;

error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
```



<!-- discussion -->

<!--
## Understanding Process Namespace Sharing
-->
## 理解进程命名空间共享

<!--
Pods share many resources so it makes sense they would also share a process
namespace. Some container images may expect to be isolated from other
containers, though, so it's important to understand these differences:
-->
Pod 共享许多资源，因此它们共享进程命名空间是很有意义的。
不过，有些容器镜像可能希望与其他容器隔离，因此了解这些差异很重要:

<!--
1. **The container process no longer has PID 1.** Some container images refuse
   to start without PID 1 (for example, containers using `systemd`) or run
   commands like `kill -HUP 1` to signal the container process. In pods with a
   shared process namespace, `kill -HUP 1` will signal the pod sandbox.
   (`/pause` in the above example.)

1. **Processes are visible to other containers in the pod.** This includes all
   information visible in `/proc`, such as passwords that were passed as arguments
   or environment variables. These are protected only by regular Unix permissions.

1. **Container filesystems are visible to other containers in the pod through the
   `/proc/$pid/root` link.** This makes debugging easier, but it also means
   that filesystem secrets are protected only by filesystem permissions.
-->

1. **容器进程不再具有 PID 1。** 在没有 PID 1 的情况下，一些容器镜像拒绝启动（例如，使用 `systemd` 的容器)，或者拒绝执行 `kill -HUP 1` 之类的命令来通知容器进程。在具有共享进程命名空间的 pod 中，`kill -HUP 1` 将通知 pod 沙箱（在上面的例子中是 `/pause`）。

2. **进程对 pod 中的其他容器可见。** 这包括 `/proc` 中可见的所有信息，例如作为参数或环境变量传递的密码。这些仅受常规 Unix 权限的保护。

3. **容器文件系统通过 `/proc/$pid/root` 链接对 pod 中的其他容器可见。** 这使调试更加容易，但也意味着文件系统安全性只受文件系统权限的保护。




