Develop, Ship and Run Any Application, Anywhere.
Docker consists of:
The Docker Engine – our lightweight and powerful open source container virtualization technology combined with a work flow for building and containerizing your applications.
Docker Hub – our SaaS service for sharing and managing your application stacks.
Docker hub（app仓库）也是docker的组成，可以在https://hub.docker.com/ 登录并注册一个docker账户，搜索、下载别人分享的docker app，也可以自己上传和保存自己修改/创建的docker app（即docker image托管）。hub repository上提供了APP非常丰富多彩，基本上囊括了常用的一切应用平台。相关资料参见：
Docker1.0发布—迈入云（DockerHub应用分发平台）端（Docker引擎）时代
http://www.openstack.cn/p1961.html
官方文档：
https://docs.docker.com/
另外官方有个在线模拟的tutorial，10分钟就可以了解docker的基本使用。
http://www.docker.com/tryit/
15个有用的docker技巧
http://www.21ops.com/linux/13512.html
1. 安装Docker
CentOS 6.5中使用epel可以直接通过yun安装：
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yum install docker-io Installed: docker-io.x86_64 0:1.0.0-6.el6 Dependency Installed: libcgroup.x86_64 0:0.40.rc1-5.el6_5.1 lxc.x86_64 0:0.9.0-2.el6 lxc-libs.x86_64 0:0.9.0-2.el6 |
# 启动docker服务
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service docker start |
2. docker的命令列表如下
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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 the containers 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 Login to the docker registry server logs Fetch the logs of a container port Lookup the public-facing port which is NAT-ed to PRIVATE_PORT pause Pause all processes within a container ps List containers pull Pull an image or a repository from the docker registry server push Push an image or a repository to the 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 in the docker index 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 # 首先我们可以查看docker的version docker version Client version: 1.0.0 Client API version: 1.12 Go version (client): go1.2.2 Git commit (client): 63fe64c/1.0.0 |
3. pull image
使用root帐号先登录hub，使用之前在docker hub上注册的帐号。如果输出的帐号和邮箱不存在，则会直接为你注册一个hub帐号。
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Usage: docker login [OPTIONS] [SERVER] Register or Login to a docker registry server, if no server is specified "https://index.docker.io/v1/" is the default. -e, --email="" Email -p, --password="" Password -u, --username="" Username docker login Username: debugo Password: Email: Login Succeeded |
比如我们在docker hub的web上搜索到
https://registry.hub.docker.com/u/williamyeh/docker-scala/tags/manage/
当然也可以使用docker search命令
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docker search scala ...... williamyeh/docker-scala Scala image for Docker (jdk 1.7.0 + Scala ... 0 [OK] ...... |
虽然这个docker app基于Debian版本的，docker会自动构建依赖层，不会影响我们的使用。
经过漫长的pulling过程后，
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Pulling repository williamyeh/docker-scala 9983413d63fa: Pulling dependent layers 511136ea3c5a: Download complete aa775e7e1cd4: Downloading complete ... |
pull完成后，可以查看images的汇总信息。
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# docker images REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE williamyeh/docker-scala latest 9983413d63fa 12 days ago 1.071 GB |
通过IMAGE ID信息，可以通过inspect命令得到JSON格式的详细的配置信息。
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docker inspect 998 [{ "Architecture": "amd64", ...... "Env": [ "HOME=/", "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" ], ] |
运行docker
docker run是最核心的命令之一，选项有很多，可以通过docker run –help来查看。
docker run williamyeh/docker-scala
有这样一个报错：unable to remount sys readonly: unable to mount sys as readonly max retries reached
可能是由于selinux的关系，Stack Overflow给出了下面的解决方法：
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vim /etc/sysconfig/docker other_args="--exec-driver=lxc --selinux-enabled" |
然后重启docker服务，再次运行即可。
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service docker restart |
这个app提供了两种方式启动：bash和scala shell
第一种是启动bash，它是以一个伪tty的方式启动的。
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-i, --interactive=false Keep stdin open even if not attached -t, --tty=false Allocate a pseudo-tty docker run -i -t williamyeh/docker-scala bash root@d7de70014d78:/home# echo "hello,docker" > /tmp/hello root@d7de70014d78:/home# exit exit |
然后ton通过docker ps 信息，-l表示最后一次创建的docker（无论是否退出）
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docker ps -l CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 952a6c45a965 williamyeh/docker-scala:latest scala 4 minutes ago Exited (0) 4 minutes ago evil_wright |
根据获得的container id提交一个新的image
docker commit 952a6c45a965 debugo/scala
7036e1f8e9791e4683a6b7b75c752723d01e1183fd10acbc2f40666634875c60
第二种是启动一个scala shell，由于指定了–rm退出则结束这个container。
–rm=false Automatically remove the container when it exits (incompatible with -d)
docker run -i –rm -t debugo/scala
root@65ad94de848a:/# scala
Welcome to Scala version 2.10.4 (Java HotSpot(TM) 64-Bit Server VM, Java 1.7.0_60).
Type in expressions to have them evaluated.
Type :help for more information.
scala> import scala.io.Source
import scala.io.Source
scala> for (line <- Source.fromFile(“/tmp/hello”).getLines) print(line)
hello,docker
说明新的image里已经包含了我们的修改，下一步我们将这个image上传到hub上，没有修改的dependencies会自动跳过。
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docker push debugo/scala The push refers to a repository [debugo/scala] (len: 1) Sending image list Pushing repository debugo/scala (1 tags) 511136ea3c5a: Image already pushed, skipping ...... |
^^
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