Dockerfile简介+Dockerfile实战

Dockerfile简介+Dockerfile实战

Dockerfile概述

Dockerfile是docker中镜像文件的的描述文件，说的直白点就是镜像文件到底是由什么东西一步步构成的。例如：你在淘宝上买了一个衣架，但是卖家并没有给你发一个完整的衣架，而是一些组件和一张图纸，你按照这个图纸一步一步将衣架组装起来，就成了你所需要的样子。那么Dockerfile 就是这张图纸，镜像文件就是你需要的这个衣架，Dockerfile 不建议随便命名，就用 Dockerfile。因此，Dockerfile其内部包含了一条条的指令，每一条指令构建一层，因此每一条指令的内容，就是描述该层应当如何构建。

Docker 执行 Dockerfile 的大致流程：

（1）docker从基础镜像运行一个容器； （2）执行一条指令并对容器作出修改；（3）执行类似dockercommit的操作提交一个新的镜像层（4）docker再基于刚提交的镜像运行一个新容器；（5）执行dockerfile中的下一条指令直到所有指令都执行完成。

回顾Dockerfile

说到Dockerfile，就离不开Dockerfile的核心组件，尤其是镜像。镜像是运行容器的基础环境，也就是说镜像是docker容器创建的关键，而创建镜像的三种方式之一的Dockerfile是最为灵活的。

1.构建~]# cd /opt/ [root@localhost opt]# mkdir apache ##创建目录 [root@localhost opt]# cd apache/ [root@localhost sshd]# vim Dockerfile ##编写dockerfile文件 #基于的基础镜像 FROM centos #维护镜像的用户信息 MAINTAINER zjz #镜像操作指令安装Apache软件 RUN yum -y update RUN yum -y install httpd #开启 80端口 EXPOSE 80 #复制网站首页文件 ADD index.html /var/www/html/index.html #将执行脚本复制到镜像中 ADD run.sh /run.sh RUN chmod 755 /run.sh #启动容器是执行脚本 CMD ["/run.sh"] 其中注意：run 命令可以有多条CMD只能有一条，若有多条则只会执行最后一条 编写启动httpd服务的shell脚本 vim run.sh #!/bin/bash rm -rf /run/httpd/* exec /usr/sbin/apachectl -D FOREGROUND 编写测试页面 vim index.html this is docker web 使用tree命令查看目录的文件结构 没有tree这个命令，用yum -y install tree 装一哈 [root@localhost apache]# tree ./ ./ ├── Dockerfile ├── index.html └── run.sh 0 directories, 3 files

构建和使用镜像（创建运行容器）

[root@localhost apache]# docker build -t .

[root@localhost apache]# docker images

#基于构建的镜像创建并运行容器，给容器取名为test [root@localhost apache]# docker run --name test -d -P apache]# docker ps -a

[root@localhost apache]# docker exec -it test /bin/bash [root@0467d8d2d590 /]# cat /var/ this is docker web

2、构建sshd镜像

[root@localhost ~]# cd /opt/ [root@localhost opt]# mkdir sshd ##创建目录 [root@localhost opt]# cd sshd/ [root@localhost sshd]# vim Dockerfile ##编写dockerfile文件 #sshd服务的镜像构建——基于Dockerfile #首先先下载基础镜像centos，创建对应的工作目录 #开始编写nginx的Dockerfile #第一步：基础镜像 FROM centos:7 #第二步：维护者信息 MAINTAINER zjz #第三步：指令集 RUN yum -y update RUN yum -y install openssh* net-tools lsof telnet passwd RUN echo '123123' | passwd --stdin root #不以PAM认证登录而是以密钥对登录（非对称密钥），即禁用ssh的PAM认证 RUN sed -i 's/UsePAM yes/UsePAM no/g' /etc/ssh/sshd_config RUN ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key #禁用ssh中PAM会话模块 RUN sed -i '/^session\s\+required\s\+pam_loginuid.so/s/^/#/' /etc/pam.d/sshd #创建ssh工作目录和权限设置 RUN mkdir -p /root/.ssh && chown root:root /root && chmod 700 /root/.ssh #开放22端口 EXPOSE 22 #第四步：启动容器时执行指令 CMD ["/usr/sbin/sshd","-D"] 构建镜像和运行容器 [root@localhost sshd]# docker run -d -P sshd:new 6005aaad0e99897e11672e081101a43aee169c06acba08a48b1353317d9504eb [root@localhost sshd]# docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 6005aaad0e99 sshd:new "/usr/sbin/sshd -D" 7 seconds ago Up 6 seconds 0.0.0.0:32768->22/tcp pensive_poincare 测试 [root@localhost sshd]# ssh 192.168.10.52 -p 32768 The authenticity of host '[192.168.10.52]:32768 ([192.168.10.52]:32768)' can't be established. RSA key fingerprint is c5:95:5d:0a:ce:b3:d8:cc:43:f7:b6:32:89:12:28:21. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added '[192.168.10.52]:32768' (RSA) to the list of known hosts. root@192.168.10.52's password: Permission denied, please try again. root@192.168.10.52's password: [root@6005aaad0e99 ~]# exit logout Connection to 192.168.10.52 closed. 此时我们登录该容器（ssh或者docker exec命令）查看sshd服务的状态（但是systemctl无法使用） [root@6005aaad0e99 ~]# systemctl status sshd Failed to get D-Bus connection: Operation not permitted 一则我们可以使用下面的命令使用该命令，二则我们可以基于上面构建的镜像作为基础镜像构建systemctl的镜像来测试验证。 [root@localhost sshd]# docker run --privileged -itd -P sshd:new /usr/sbin/init bf552af2fb6b7d512bc44c32262a5dcce092e26bb7bec8e73c866a5c5a755d83 [root@localhost sshd]# docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES bf552af2fb6b sshd:new "/usr/sbin/init" 6 seconds ago Up 6 seconds 0.0.0.0:32770->22/tcp adoring_bose bb24b2efd442 systemctl:new "/usr/sbin/init" 13 minutes ago Up 13 minutes 22/tcp sleepy_curie 0467d8d2d590 "/run.sh" 27 minutes ago Up 27 minutes 0.0.0.0:32769->80/tcp test 6005aaad0e99 sshd:new "/usr/sbin/sshd -D" About an hour ago Up About an hour 0.0.0.0:32768->22/tcp pensive_poincare [root@localhost sshd]# ssh 192.168.10.52 -p 32770 The authenticity of host '[192.168.10.52]:32770 ([192.168.10.52]:32770)' can't be established. ECDSA key fingerprint is e7:5b:57:32:ea:12:db:90:c5:da:d5:3d:95:ff:48:ab. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added '[192.168.10.52]:32770' (ECDSA) to the list of known hosts. root@192.168.10.52's password: [root@bf552af2fb6b ~]# systemctl status sshd ● sshd.service - OpenSSH server daemon Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled) Active: active (running) since Tue 2020-07-28 02:55:53 UTC; 48s ago Docs: man:sshd(8) man:sshd_config(5) Main PID: 75 (sshd) CGroup: /docker/bf552af2fb6b7d512bc44c32262a5dcce092e26bb7bec8e73c866a5c5a755d83/system.slice/sshd.service ├─ 75 /usr/sbin/sshd -D ├─ 85 sshd: root@pts/1 ├─ 89 -bash └─102 systemctl status sshd ‣ 75 /usr/sbin/sshd -D Jul 28 02:55:53 bf552af2fb6b systemd[1]: Starting OpenSSH server daemon... Jul 28 02:55:53 bf552af2fb6b sshd[75]: Server listening on 0.0.0.0 port 22. Jul 28 02:55:53 bf552af2fb6b sshd[75]: WARNING: 'UsePAM no' is not supported in Red Hat Enterprise Linux and ...lems. Jul 28 02:55:53 bf552af2fb6b sshd[75]: Server listening on :: port 22. Jul 28 02:55:53 bf552af2fb6b systemd[1]: Started OpenSSH server daemon. Jul 28 02:56:23 bf552af2fb6b sshd[85]: WARNING: 'UsePAM no' is not supported in Red Hat Enterprise Linux and ...lems. Jul 28 02:56:27 bf552af2fb6b sshd[85]: Failed password for root from 192.168.10.52 port 35474 ssh2 Jul 28 02:56:29 bf552af2fb6b sshd[85]: Failed password for root from 192.168.10.52 port 35474 ssh2 Jul 28 02:56:31 bf552af2fb6b sshd[85]: Accepted password for root from 192.168.10.52 port 35474 ssh2 Hint: Some lines were ellipsized, use -l to show in full.

3、构建systemctl镜像

[root@localhost ~]# cd /opt/ [root@localhost opt]# mkdir systemctl ##创建目录 [root@localhost opt]# cd systemctl/ [root@localhost sshd]# vim Dockerfile ##编写dockerfile文件 FROM sshd:new MAINTAINER zjz ENV container docker #下面的命令是放在一个镜像层中执行的，可以减少镜像层 #括号中的指令含义是遍历进入的目录文件，删除除了systemd-tmpfiles-setup.service的所有文件,之后删除一些其他文件 RUN (cd /lib/systemd/system/sysinit.target.wants/; for i in *; do [ $i == systemd-tmpfiles-setup.service ] || rm -f $i; done); \ rm -f /lib/systemd/system/multi-user.target.wants/*; \ rm -f /etc/systemd/system/*.wants/*; \ rm -f /lib/systemd/system/local-fs.target.wants/*; \ rm -f /lib/systemd/system/sockets.target.wants/*udev*; \ rm -f /lib/systemd/system/sockets.target.wants/*initctl*; \ rm -f /lib/systemd/system/basic.target.wants/*; \ rm -f /lib/systemd/system/anaconda.target.wants/*; VOLUME [ "/sys/fs/cgroup" ] CMD ["/usr/sbin/init"]

构建运行及测试

[root@localhost systemctl]# docker build -t systemctl:new . ##创建镜像 [root@localhost systemctl]# docker run --privileged -it -v /sys/fs/cgroup/:/sys/fs/cgroup:ro systemctl:new /usr/sbin/init ##privateged container 内的root拥有真正的root权限，否则，container内的root只是外部的一个普通用户权限。 systemd 219 running in system mode. (+PAM +AUDIT +SELINUX +IMA -APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 -SECCOMP +BLKID +ELFUTILS +KMOD +IDN) Detected virtualization docker. Detected architecture x86-64. Welcome to CentOS Linux 7 (Core)! Set hostname to . [ OK ] Created slice Root Slice. [ OK ] Listening on Journal Socket. [ OK ] Created slice System Slice. [ OK ] Reached target Slices. [ OK ] Reached target Paths. [ OK ] Listening on Delayed Shutdown Socket. [ OK ] Reached target Local File Systems. Starting Create Volatile Files and Directories... [ OK ] Reached target Swap. Starting Journal Service... [ OK ] Started Create Volatile Files and Directories. [ INFO ] Update UTMP about System Boot/Shutdown is not active. [DEPEND] Dependency failed for Update UTMP about System Runlevel Changes. Job systemd-update-utmp-runlevel.service/start failed with result 'dependency'. [ OK ] Started Journal Service. [ OK ] Reached target System Initialization. [ OK ] Listening on D-Bus System Message Bus Socket. [ OK ] Reached target Sockets. [ OK ] Reached target Basic System. [ OK ] Reached target Multi-User System. [ OK ] Started Daily Cleanup of Temporary Directories. [ OK ] Reached target Timers.

重新开启一个终端进行测试

[root@localhost ~]# cd /opt/ [root@localhost opt]# cd systemctl/ [root@localhost systemctl]# docker ps -a [root@localhost systemctl]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES bb24b2efd442 systemctl:new "/usr/sbin/init" 9 minutes ago Up 9 minutes 22/tcp sleepy_curie 0467d8d2d590 "/run.sh" 23 minutes ago Up 23 minutes 0.0.0.0:32769->80/tcp test 6005aaad0e99 sshd:new "/usr/sbin/sshd -D" 44 minutes ago Up 44 minutes 0.0.0.0:32768->22/tcp pensive_poincare [root@localhost systemctl]# docker exec -it sleepy_curie /bin/bash [root@bb24b2efd442 /]# systemctl status sshd ● sshd.service - OpenSSH server daemon Loaded: loaded (/usr/lib/systemd/system/sshd.service; disabled; vendor preset: enabled) Active: inactive (dead) Docs: man:sshd(8) man:sshd_config(5) [root@bb24b2efd442 /]# ssh 192.168.10.52 -p 22 The authenticity of host '192.168.10.52 (192.168.10.52)' can't be established. ECDSA key fingerprint is SHA256:X3dOS5bVumqe/7loOyPanoa7rXqlTF79C5mavP1EQW0. ECDSA key fingerprint is MD5:00:8f:be:85:3b:97:c9:05:bb:fb:fe:17:14:49:19:9f. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added '192.168.10.52' (ECDSA) to the list of known hosts. root@192.168.10.52's password: Last failed login: Tue Jul 28 10:46:42 CST 2020 from 172.17.0.4 on ssh:notty There were 2 failed login attempts since the last successful login. Last login: Tue Jul 28 10:43:54 2020 from 192.168.10.1 [root@localhost ~]# exit logout Connection to 192.168.10.52 closed. [root@bb24b2efd442 /]# exit exit

4.构建Nginx镜像

[root@localhost ~]# cd /opt/ [root@localhost opt]# mkdir nginx ##创建Nginx目录 [root@localhost opt]# cd nginx/ [root@localhost nginx]# vim Dockerfile FROM centos:7 MAINTAINER The is nginx RUN yum install -y proc-devel gcc gcc-c++ zlib zlib-devel make openssl-devel wget ADD nginx-1.14.0.tar.gz /usr/local WORKDIR /usr/local/nginx-1.14.0/ RUN ./configure --prefix=/usr/local/nginx && make && make install EXPOSE 80 EXPOSE 443 RUN echo "daemon off;">>/usr/local/nginx/conf/nginx.conf WORKDIR /root/nginx ADD run.sh /run.sh RUN chmod 755 /run.sh CMD ["/run.sh"] [root@localhost nginx]# vim run.sh #!/bin/bash /usr/local/nginx/sbin/nginx ##开启Nginx服务 [root@localhost nginx]# rz ##在xshell里上传nginx安装包 [root@localhost nginx]# ls nginx-1.14.0.tar.gz [root@localhost nginx]# docker build -t nginx:new . ##创建镜像 [root@localhost nginx]# docker run -d -P nginx:new ##创建容器 ba75ff06051430938bbb014450cd16f7b2b7a2fe023969a6a0ec76051d6872c5 [root@localhost nginx]# docker ps -a ##查看容器 CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES ba75ff060514 nginx:new "/run.sh" 14 seconds ago Up 14 seconds 0.0.0.0:32772->80/tcp, 0.0.0.0:32771->443/tcp pedantic_archimedes

5.构建Tomcat镜像

[root@localhost opt]# mkdir tomcat [root@localhost opt]# cd tomcat/ [root@localhost tomcat]# rz [root@localhost tomcat]# ls jdk-8u211-linux-x64.tar.gz [root@localhost tomcat]# rz [root@localhost tomcat]# ls apache-tomcat-8.5.35.tar.gz jdk-8u211-linux-x64.tar.gz [root@localhost tomcat]# vim Dockerfile FROM centos:7 MAINTAINER this is tomcat ADD jdk-8u211-linux-x64.tar.gz /usr/local WORKDIR /usr/local RUN mv jdk1.8.0_211 /usr/local/java ENV JAVA_HOME /usr/local/java ##设置环境变量 ENV JAVA_BIN /usr/local/java/bin ENV JRE_HOME /usr/local/java/jre ENV PATH $PATH:/usr/local/java/bin:/usr/local/java/jre/bin ENV CLASSPATH /usr/local/java/jre/bin:/usr/local/java/lib:/usr/local/java/jre/lib/charsets.jar ADD apache-tomcat-8.5.35.tar.gz /usr/local WORKDIR /usr/local RUN mv apache-tomcat-8.5.35 /usr/local/tomcat8 EXPOSE 8080 ENTRYPOINT ["/usr/local/tomcat8/bin/catalina.sh","run"] [root@localhost tomcat]# docker build -t tomcat:centos . ##创建镜像 [root@localhost tomcat]# docker run --name tomcat01 -p 1234:8080 -it tomcat:centos /bin/bash ##创建容器 [root@localhost tomcat]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 3f81e707d8b6 tomcat:centos "/usr/local/tomcat8/…" 3 minutes ago Up 3 minutes 0.0.0.0:1234->8080/tcp tomcat01

6.构建MySQL镜像

[root@localhost mysql5.7]# cat Dockerfile #基于基础镜像 FROM centos:7 #维护该镜像的用户信息 MAINTAINER zjz #指令集 #下载相关工具 RUN yum -y install \ ncurses \ ncurses-devel \ bison \ cmake \ make \ gcc \ gcc-c++ #创建mysql用户 RUN useradd -s /sbin/nologin mysql #复制软件包到指定目录（将会自动解压） ADD mysql-boost-5.7.20.tar.gz /usr/local/src #指定工作目录 WORKDIR /usr/local/src/mysql-5.7.20/ #cmake配置及编译安装 RUN cmake \ -DCMAKE_INSTALL_PREFIX=/usr/local/mysql \ -DMYSQL_UNIX_ADDR=/usr/local/mysql/mysql.sock \ -DSYSCONFDIR=/etc \ -DSYSTEMD_PID_DIR=/usr/local/mysql \ -DDEFAULT_CHARSET=utf8 \ -DDEFAULT_COLLATION=utf8_general_ci \ -DWITH_INNOBASE_STORAGE_ENGINE=1 \ -DWITH_ARCHIVE_STORAGE_ENGINE=1 \ -DWITH_BLACKHOLE_STORAGE_ENGINE=1 \ -DWITH_PERFSCHEMA_STORAGE_ENGINE=1 \ -DMYSQL_DATADIR=/usr/local/mysql/data \ -DWITH_BOOST=boost \ -DWITH_SYSTEMD=1 && make && make install #更改mysql目录属主属组 RUN chown -R mysql:mysql /usr/local/mysql/ #删除默认安装的my.cnf文件 RUN rm -rf /etc/my.cnf #复制一份my.cnf到etc目录下 ADD my.cnf /etc #更改该文件权限 RUN chown mysql:mysql /etc/my.cnf #设置环境变量，命令目录及库文件目录 ENV PATH=/usr/local/mysql/bin:/usr/local/mysql/lib:$PATH #指定工作目录 WORKDIR /usr/local/mysql/ #初始化设置 RUN bin/mysqld \ --initialize-insecure \ --user=mysql \ --basedir=/usr/local/mysql \ --datadir=/usr/local/mysql/data #优化启动方式 RUN cp /usr/local/mysql/usr/lib/systemd/system/mysqld.service /usr/lib/systemd/system/ EXPOSE 3306 #直接设置运行启动脚本 RUN echo -e "#!/bin/sh \nsystemctl enable mysqld" > /run.sh RUN chmod 755 /run.sh RUN sh /run.sh #启动容器时执行 CMD ["init"]

my.cnf文件

[client] port = 3306 default-character-set=utf8 socket = /usr/local/mysql/mysql.sock [mysql] port = 3306 default-character-set=utf8 socket = /usr/local/mysql/mysql.sock [mysqld] user = mysql basedir = /usr/local/mysql datadir = /usr/local/mysql/data port = 3306 character_set_server=utf8 pid-file = /usr/local/mysql/mysqld.pid socket = /usr/local/mysql/mysql.sock server-id = 1 sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_AUTO_VALUE_ON_ZERO,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,PIPES_AS_CONCAT,ANSI_QUOTES

构建及运行

[root@localhost mysql5.7]# docker build -t mysql:latest . ...//友情提示MySQL5.7时间比较长 [root@localhost mysql5.7]# docker run --name mysql_new -d -P --privileged mysql:latest e9c9f93766d149a3387aed4cb5e04425269a884fccf06256b087d00e4c262222 [root@localhost mysql5.7]# docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES e9c9f93766d1 mysql:latest "init" 6 seconds ago Up 5 seconds 0.0.0.0:32774->3306/tcp

进入MySQL服务的容器中进行提权操作

[root@localhost mysql5.7]# docker exec -it mysql_new /bin/bash [root@e9c9f93766d1 mysql]# mysql Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 3 Server version: 5.7.20 Source distribution Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> grant all privileges on *.* to 'root'@'%' identified by '123456'; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> flush privileges; Query OK, 0 rows affected (0.01 sec) mysql> exit Bye [root@e9c9f93766d1 mysql]# exit exit

宿主机系统安装mariadb服务来测试

[root@localhost mysql5.7]# yum install mariadb -y [root@localhost mysql5.7]# mysql -h 20.0.0.149 -P 32774 -uroot -p123456 Welcome to the MariaDB monitor. Commands end with ; or \g. Your MySQL connection id is 4 Server version: 5.7.20 Source distribution Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MySQL [(none)]> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ 4 rows in set (0.01 sec) #创建一个数据库，退出后再次然后进入容器查看 MySQL [(none)]> create database mydb; Query OK, 1 row affected (0.00 sec) MySQL [(none)]> exit Bye [root@localhost mysql5.7]# docker exec -it mysql_new /bin/bash [root@e9c9f93766d1 mysql]# mysql Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 5 Server version: 5.7.20 Source distribution Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mydb | | mysql | | performance_schema | | sys | +--------------------+ 5 rows in set (0.00 sec) mysql> exit Bye [root@e9c9f93766d1 mysql]# exit exit [root@localhost mysql5.7]#

工程中一般不会将MySQL服务放在容器中运行，而是会单独使用服务器部署提供服务（搭建高可用集群架构）

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