Docker

CentOS7下安装Docker（一）

一、配置yum源

一般来说，安装好centos7后，通过命令查看已有yum源会看到7个.repo;

[root@rainbowzj ~]# ls /etc/yum.repos.d/CentOS-Base.repo  CentOS-Debuginfo.repo  CentOS-Media.repo    CentOS-Vault.repo   CentOS-CR.repo    CentOS-fasttrack.repo  CentOS-Sources.repo  

而要安装Docker，则需要配置额外yum源，命令如下；(此为博主安装Elasticsearch配置的源，也可以添加其它yum源如阿里源等)

[root@rainbowzj ~]# vi /etc/yum.repos.d/elasticsearch.repo#创建的为新文件，写入如下语句[elasticsearch-5.x]name=Elasticsearch repository for 5.x packagesbaseurl=https://artifacts.elastic.co/packages/5.x/yumgpgcheck=1gpgkey=https://artifacts.elastic.co/GPG-KEY-elasticsearchenabled=1autorefresh=1type=rpm-md[root@rainbowzj ~]# yum insatll -y epel-release再次查看发现yum源数量如下：[root@rainbowzj ~]# ls /etc/yum.repos.d/CentOS-Base.repo  CentOS-Debuginfo.repo  CentOS-Media.repo    CentOS-Vault.repo   epel.repoCentOS-CR.repo    CentOS-fasttrack.repo  CentOS-Sources.repo  elasticsearch.repo  epel-testing.repo

二、安装docker

[root@rainbowzj ~]# yum -y install docker[root@rainbowzj ~]# systemctl start docker[root@rainbowzj ~]# systemctl enable docker

三、下载及创建容器

[root@rainbowzj ~]# docker pull centos#此过程可能很慢[root@rainbowzj ~]#docker run centos /bin/echo "Welcome to the Docker World"Welcome to the Docker World [root@rainbowzj ~]#docker run -i -t centos /bin/bash#进入docker内，使用uname -a查看内核信息，之后使用exit退出；[root@rainbowzj ~]#docker ps（在不关闭docker的情况下，查看docker进程信息）CONTAINER ID        IMAGE                   COMMAND             CREATED              STATUS              PORTS                  NAMESc21f34efc5b7        my_image/centos_httpd   "/bin/bash"         About a minute ago   Up About a minute   0.0.0.0:8081->80/tcp   angry_noyce[root@rainbowzj ~]#docker attach c21f34efc5b7#连接成功[root@c21f34efc5b7 /]##使用exit，返回[root@rainbowzj ~]# docker run -it -p 8081:80 my_image/centos_httpd /bin/bash[root@c21f34efc5b7 /]# /usr/sbin/httpd   AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using 172.17.0.2. Set the 'ServerName' directive globally to suppress this messagehttpd (pid 21) already running[root@c21f34efc5b7 /]# echo "httpd on Docker Container" > /var/www/html/index.html 验证是否成功：[root@c21f34efc5b7 /]# curl localhosthttpd on Docker Container#成功[root@rainbowzj ~]#docker kill c21f34efc5b7[root@rainbowzj ~]# docker psCONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES

四、使用Dockerfile

Dockerfile常用指令：

INSTRUCTION Description FROM iIt sets the Base Image for subsequent instructions. MAINTAINER It sets the Author field of the generated images. RUN It will execute any commands when Docker image will be created. CMD It will execute any commands when Docker container will be executed. ENTRYPOINT It will execute any commands when Docker container will be executed. LABEL It adds metadata to an image. EXPOSE It informs Docker that the container will listen on the specified network ports at runtime. ENV It sets the environment variable. ADD It copies new files, directories or remote file URLs. COPY It copies new files or directories.The differences of [ADD] are that it’s impossible to specify remore URL and also it will not extract archive files automatically. VOLUME It creates a mount point with the specified name and marks it as holding externally mounted volumes from native host or other containers USER It sets the user name or UID. WORKDIR It sets the working directory. 指令 描述 from 基于什么镜像 maintainer 镜像的创建者 run 在后面添加创建镜像时执行的命令 cmd 在后面添加创建容器时执行的命令 entrypoint 在后面添加创建容器时执行的命令（无cmd的可替换性） label 给镜像添加元数据 expose 让docker容器在运行时在指定的端口上映射 env 环境变量的设置 add 复制新文件，目录，远程URL文件 copy 复制新的文件与目录，与add的区别可指定URL文件与读取存档文件 volume 将本地文件夹或者其他container的文件夹挂载到container中。 user 设置用户或UID workdir 设置工作目录