通过上一节的学习，我们知道如何运行docker容器，我们运行了一个普通的，一个后台的，我们还学习了几个指令：

docker ps - Lists containers.
docker logs - Shows us the standard output of a container.
docker stop - Stops running containers.

我们还可以查看下docker的版本：

root@iZ28ikebrg6Z:~# docker version
Client version: 1.2.0
Client API version: 1.14
Go version (client): go1.3.1
Git commit (client): fa7b24f
OS/Arch (client): linux/amd64
Server version: 1.2.0
Server API version: 1.14
Go version (server): go1.3.1
Git commit (server): fa7b24f
root@iZ28ikebrg6Z:~# 

docker是基于google公司的Go语言的。

如果不知道docker怎么用，或者忘记了的时候，直接输入docker，会给出用法提示

root@iZ28ikebrg6Z:~# docker
Usage: docker [OPTIONS] COMMAND [arg...]
 -H=[unix:///var/run/docker.sock]: tcp://host:port to bind/connect to or unix://path/to/socket to use

A self-sufficient runtime for linux containers.

Commands:
    attach    Attach to a running container
    build     Build an image from a Dockerfile
    commit    Create a new image from a container's changes
    cp        Copy files/folders from a container's filesystem to the host path
    diff      Inspect changes on a container's filesystem
    events    Get real time events from the server
    export    Stream the contents of a container as a tar archive
    history   Show the history of an image
    images    List images
    import    Create a new filesystem image from the contents of a tarball
    info      Display system-wide information
    inspect   Return low-level information on a container
    kill      Kill a running container
    load      Load an image from a tar archive
    login     Register or log in to a Docker registry server
    logout    Log out from a Docker registry server
    logs      Fetch the logs of a container
    port      Lookup the public-facing port that is NAT-ed to PRIVATE_PORT
    pause     Pause all processes within a container
    ps        List containers
    pull      Pull an image or a repository from a Docker registry server
    push      Push an image or a repository to a Docker registry server
    restart   Restart a running container
    rm        Remove one or more containers
    rmi       Remove one or more images
    run       Run a command in a new container
    save      Save an image to a tar archive
    search    Search for an image on the Docker Hub
    start     Start a stopped container
    stop      Stop a running container
    tag       Tag an image into a repository
    top       Lookup the running processes of a container
    unpause   Unpause a paused container
    version   Show the Docker version information
    wait      Block until a container stops, then print its exit code

root@iZ28ikebrg6Z:~# 

docker后面跟指令，

root@iZ28ikebrg6Z:~# docker attach

Usage: docker attach [OPTIONS] CONTAINER

Attach to a running container

  --no-stdin=false    Do not attach STDIN
  --sig-proxy=true    Proxy all received signals to the process (even in non-TTY mode). SIGCHLD, SIGKILL, and SIGSTOP are not proxied.
root@iZ28ikebrg6Z:~# 

如果输入非法，总是会给出提示，告诉你怎么用。

Running a Web Application in Docker

利用Docker构建一个web程序

我们执行一个web应用。

root@iZ28ikebrg6Z:~# docker run -d -P training/weapp python app.py
Unable to find image 'training/weapp' locally
Pulling repository training/weapp
2014/10/16 11:01:56 Error: image training/weapp not found
root@iZ28ikebrg6Z:~# docker run -d -P training/webapp python app.py
Unable to find image 'training/webapp' locally
Pulling repository training/webapp
31fa814ba25a: Pulling dependent layers 
511136ea3c5a: Download complete 
f10ebce2c0e1: Download complete 
82cdea7ab5b5: Download complete 
5dbd9cb5a02f: Download complete 
31fa814ba25a: Download complete 
64523f641a05: Download complete 
0e2afc9aad6e: Download complete 
e8fc7643ceb1: Download complete 
733b0e3dbcee: Download complete 
a1feb043c441: Download complete 
e12923494f6a: Download complete 
a15f98c46748: Download complete 
09792841c0b448a330a89ee656b4a16605d835f9d43bb7d6f80f204b6e8ed5b2
root@iZ28ikebrg6Z:~# docker ps
CONTAINER ID        IMAGE                    COMMAND             CREATED             STATUS              PORTS                     NAMES
09792841c0b4        training/webapp:latest   "python app.py"     54 minutes ago      Up 54 minutes       0.0.0.0:49153->5000/tcp   compassionate_torvalds   
root@iZ28ikebrg6Z:~# docker ps
CONTAINER ID        IMAGE                    COMMAND             CREATED             STATUS              PORTS                     NAMES
09792841c0b4        training/webapp:latest   "python app.py"     56 minutes ago      Up 56 minutes       0.0.0.0:49153->5000/tcp   compassionate_torvalds   
root@iZ28ikebrg6Z:~# 

第一次敲错了。第二次它会去docker库下载，下载完了，ps查看一下。多了一行Ports。表示将本机的49153端口映射到compassionate_toralds容器的5000端口。

我用浏览器试一下。-d选项，我们已经讲过，是将程序后台化；-P，大写的P，是让docker来指定一个端口映射。这里是49153,你可以通过-p小写的来指定这种映射关系。

如下效果：

好，可以访问。哈哈。

root@iZ28ikebrg6Z:~# docker run -d -p 5000:5000 training/webapp python app.py
aa47ba8e71c8512f228a96bf80da117b6c86fc03bdb17eef1c2db353a3e18493

好，再访问一下。