> For the complete documentation index, see [llms.txt](https://hezhiqiang.gitbook.io/docker/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hezhiqiang.gitbook.io/docker/network/port_mapping.md).

# 外部访问容器

容器中可以运行一些网络应用，要让外部也可以访问这些应用，可以通过 `-P` 或 `-p` 参数来指定端口映射。

当使用 `-P` 标记时，Docker 会随机映射一个 `49000~49900` 的端口到内部容器开放的网络端口。

使用 `docker container ls` 可以看到，本地主机的 49155 被映射到了容器的 5000 端口。此时访问本机的 49155 端口即可访问容器内 web 应用提供的界面。

```bash
$ docker run -d -P training/webapp python app.py

$ docker container ls -l
CONTAINER ID  IMAGE                   COMMAND       CREATED        STATUS        PORTS                    NAMES
bc533791f3f5  training/webapp:latest  python app.py 5 seconds ago  Up 2 seconds  0.0.0.0:49155->5000/tcp  nostalgic_morse
```

同样的，可以通过 `docker logs` 命令来查看应用的信息。

```bash
$ docker logs -f nostalgic_morse
* Running on http://0.0.0.0:5000/
10.0.2.2 - - [23/May/2014 20:16:31] "GET / HTTP/1.1" 200 -
10.0.2.2 - - [23/May/2014 20:16:31] "GET /favicon.ico HTTP/1.1" 404 -
```

`-p` 则可以指定要映射的端口，并且，在一个指定端口上只可以绑定一个容器。支持的格式有 `ip:hostPort:containerPort | ip::containerPort | hostPort:containerPort`。

## 映射所有接口地址

使用 `hostPort:containerPort` 格式本地的 5000 端口映射到容器的 5000 端口，可以执行

```bash
$ docker run -d -p 5000:5000 training/webapp python app.py
```

此时默认会绑定本地所有接口上的所有地址。

## 映射到指定地址的指定端口

可以使用 `ip:hostPort:containerPort` 格式指定映射使用一个特定地址，比如 localhost 地址 127.0.0.1

```bash
$ docker run -d -p 127.0.0.1:5000:5000 training/webapp python app.py
```

## 映射到指定地址的任意端口

使用 `ip::containerPort` 绑定 localhost 的任意端口到容器的 5000 端口，本地主机会自动分配一个端口。

```bash
$ docker run -d -p 127.0.0.1::5000 training/webapp python app.py
```

还可以使用 `udp` 标记来指定 `udp` 端口

```bash
$ docker run -d -p 127.0.0.1:5000:5000/udp training/webapp python app.py
```

## 查看映射端口配置

使用 `docker port` 来查看当前映射的端口配置，也可以查看到绑定的地址

```bash
$ docker port nostalgic_morse 5000
127.0.0.1:49155.
```

注意：

* 容器有自己的内部网络和 ip 地址（使用 `docker inspect` 可以获取所有的变量，Docker 还可以有一个可变的网络配置。）
* `-p` 标记可以多次使用来绑定多个端口

例如

```bash
$ docker run -d \
    -p 5000:5000 \
    -p 3000:80 \
    training/webapp \
    python app.py
```


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