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。
