【Docker学习之五】Docker自定义镜像示例

环境
　　docker-ce-19.03.1-3.el7.x86_64
　　centos 7

一、创建centos+jdk+tomcat镜像

对于公用的容器比如，tomcat、nginx、mysql等应用组件可以直接使用官方的容器，不必自己创建；如果需要创建自定义容器，需要下载对应软件官网tar包进行挂载。

1、准备基础镜像和tar包
使用centos7作为基础镜像

[root@node105 ~]# docker pull centos:7
[root@node105 ~]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
centos                                 67fa590cfc1c         days ago          202MB

[root@node105 src]# cd /usr/local/src && ll
total
-rw-r--r--. 1 root root   9722154 Aug 25 15:47 apache-tomcat-8.5.45.tar.gz
-rw-r--r--. 1 root root 181260798 Aug 25 15:45 jdk-8u65-linux-x64.tar.gz

2、创建Dockerfile

[root@node105 src]# vi centos-jdk-tomcat-Dockerfile
#使用的基础镜像
FROM centos:
#作者信息
MAINTAINER cac2020 "cac2020@163.com"

#使用ADD指令会直接对tar.gz进行解压缩，不用再单独的tar解压jdk了
ADD jdk-8u65-linux-x64.tar.gz /usr/local
ADD apache-tomcat-8.5..tar.gz /usr/local

#添加环境变量
ENV JAVA_HOME /usr/local/jdk1..0_65
ENV CLASSPATH $JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
ENV CATALINA_HOME /usr/local/apache-tomcat-8.5.
ENV PATH $PATH:$JAVA_HOME/bin:$CATALINA_HOME/bin

#暴露8080端口
EXPOSE 

#启动时运行tomcat
CMD ["/usr/local/apache-tomcat-8.5.45/bin/catalina.sh","run"]

3、使用Dockerfile创建镜像

[root@node105 src]# docker build -t centos-jdk-tomcat:0.0. . -f centos-jdk-tomcat-Dockerfile
Sending build context to Docker daemon    191MB
Step / : FROM centos:
 ---> 67fa590cfc1c
Step / : MAINTAINER cac2020 "cac2020@163.com"
 ---> Running in b48a9a1c9456
Removing intermediate container b48a9a1c9456
 ---> cf88aebfb290
Step / : ADD jdk-8u65-linux-x64.tar.gz /usr/local
 ---> a80fd8584d3e
Step / : ADD apache-tomcat-8.5..tar.gz /usr/local
 ---> 3951fd837bd5
Step / : ENV JAVA_HOME /usr/local/jdk1..0_65
 ---> Running in 8ea280c20bbe
Removing intermediate container 8ea280c20bbe
 ---> 5e2c39e6b557
Step / : ENV CLASSPATH $JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
 ---> Running in 7dfbb7d72fd6
Removing intermediate container 7dfbb7d72fd6
 ---> 2651de66a845
Step / : ENV CATALINA_HOME /usr/local/apache-tomcat-8.5.
 ---> Running in 490f9dd59d99
Removing intermediate container 490f9dd59d99
 ---> 70ff0149c070
Step / : ENV PATH $PATH:$JAVA_HOME/bin:$CATALINA_HOME/bin
 ---> Running in 867f19619c72
Removing intermediate container 867f19619c72
 ---> 8a1b71576d7b
Step / : EXPOSE
 ---> Running in 13d2b33647d2
Removing intermediate container 13d2b33647d2
 ---> 341bc406be44
Step / : CMD ["/usr/local/apache-tomcat-8.5.45/bin/catalina.sh","run"]
 ---> Running in 88f261af47f4
Removing intermediate container 88f261af47f4
 ---> e77fdb372830
Successfully built e77fdb372830
Successfully tagged centos-jdk-tomcat:0.0.
[root@node105 src]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
centos-jdk-tomcat   0.0.1               e77fdb372830         seconds ago      581MB
centos                                 67fa590cfc1c         days ago          202MB

备注：
(1)-t 指定镜像的名称和tag；
(2)使用-f 指定要使用的dockerfile，如果不指定会寻找当前目录名为Dockerfile的文件
(3)上面有个 . ,这个表示当前目录，必不可少的

4、运行创建的镜像

交互方式：

#jdk
[root@node105 src]# docker run -d -it centos-jdk-tomcat:0.0.1 /bin/bash
[root@node105 src]# docker ps
CONTAINER ID        IMAGE                     COMMAND                  CREATED             STATUS              PORTS                     NAMES
ded73f70822e        centos-jdk-tomcat:0.0.   "/bin/bash"               seconds ago       Up  seconds        /tcp                  happy_lumiere

注意：创建容器的时候一定要使用 -it /bin/bash这种方式，要不然jdk的容器起不来。

#tomcat
[root@node105 src]# docker run -d -p 8080:8080 --name test-tomcat centos-jdk-tomcat:0.0.1
b40394ee475007969c8654e5b297f49a370d313655a8785ad3cda6a4dab81948
[root@node105 src]# docker ps
CONTAINER ID        IMAGE                     COMMAND                  CREATED             STATUS              PORTS                    NAMES
b40394ee4750        centos-jdk-tomcat:0.0.   "/usr/local/apache-t…"    seconds ago       Up  seconds        0.0.0.0:->/tcp   test-tomcat
a74ccebbe32e        centos-jdk-tomcat:0.0.   "/bin/bash"               minutes ago       Up  minutes        /tcp                 centos-jdk-tomcat
[root@node105 src]# 

5、验证

#jdk
[root@node105 src]# docker exec -it a7 /bin/bash
[root@a74ccebbe32e /]# java -version
java version "1.8.0_65"
Java(TM) SE Runtime Environment (build 1.8.0_65-b17)
Java HotSpot(TM) -Bit Server VM (build 25.65-b01, mixed mode)
[root@a74ccebbe32e /]# exit
exit

#tomcat

参考：

使用Dockerfile方式创建镜像:
docker创建jdk镜像 
从零开始构建一个centos+jdk7+tomcat7的镜像文件

使用-it交互方式一步一步设置最后commit创建镜像:
docker环境搭建centos+jdk+tomcat_CENTOS篇

二、supervisor
Docker 容器在启动的时候开启单个进程，比如，一个 ssh 或者 apache 的 daemon 服务。但我们经常需要在一个机器上开启多个服务，这可以有很多方法，最简单的就是把多个启动命令放到一个启动脚本里面，启动的时候直接启动这个脚本，另外就是安装进程管理工具，比如supervisor。使用进程管理工具 supervisor 来管理容器中的多个进程。使用 Supervisor 可以更好的控制、管理、重启我们希望运行的进程。

1、准备工作
(1)概念理解：
supervisor：要安装的软件的名称。
supervisord：装好supervisor软件后，supervisord用于启动supervisor服务。
supervisorctl：用于管理supervisor配置文件中program。

(2)软件安装：linux本地机器需要安装supervisor，源码安装或者yum安装或者python pip安装，这里使用yum安装

#centos7下yum安装supervisor
[root@node105 local]# yum install epel-release
[root@node105 local]# yum install -y supervisor

# 开机自启动
[root@node105 local]# systemctl enable supervisord
Created symlink from /etc/systemd/system/multi-user.target.wants/supervisord.service to /usr/lib/systemd/system/supervisord.service.

# 启动supervisord服务
[root@node105 local]# systemctl start supervisord

# 查看supervisord服务状态
[root@node105 local]# systemctl status supervisord
● supervisord.service - Process Monitoring and Control Daemon
   Loaded: loaded (/usr/lib/systemd/system/supervisord.service; enabled; vendor preset: disabled)
   Active: active (running) since Sun -- :: CST; 41s ago
  Process:  ExecStart=/usr/bin/supervisord -c /etc/supervisord.conf (code=exited, status=/SUCCESS)
 Main PID:  (supervisord)
    Tasks:
   Memory: 10.9M
   CGroup: /system.slice/supervisord.service
           └─ /usr/bin/python /usr/bin/supervisord -c /etc/supervisord.conf

Aug  :: node105 systemd[]: Starting Process Monitoring and Control Daemon...
Aug  :: node105 systemd[]: Started Process Monitoring and Control Daemon.

# 查看是否存在supervisord进程
[root@node105 local]# ps -ef|grep supervisord
root             : ?        :: /usr/bin/python /usr/bin/supervisord -c /etc/supervisord.conf
root          : pts/    :: grep --color=auto supervisord
[root@node105 local]#

2、容器中如何同时使用ssh和tomcat 服务
(1)创建Dockerfile文件

[root@node105 docker]# vi Dockerfile
FROM centos:
MAINTAINER cac2020 "cac2020@163.com"

#ssh
RUN yum install -y openssh openssh-server openssh-clients
RUN mkdir /var/run/sshd
RUN ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key
RUN ssh-keygen -t dsa -f /etc/ssh/ssh_host_dsa_key
RUN sed -i 's/#UseDNS yes/UseDNS no/g' /etc/ssh/sshd_config
RUN sed -i 's/GSSAPIAuthentication yes/GSSAPIAuthentication no/g' /etc/ssh/sshd_config
RUN /bin/echo 'root:123456' |chpasswd
RUN /bin/sed -i 's/.*session.*required.*pam_loginuid.so.*/session optional pam_loginuid.so/g' /etc/pam.d/sshd
RUN /bin/echo -e "LANG=\"en_US.UTF-8\"" > /etc/default/local

#tomcat
#使用ADD指令会直接对tar.gz进行解压缩，不用再单独的tar解压jdk了
ADD jdk-8u65-linux-x64.tar.gz /usr/local
ADD apache-tomcat-8.5..tar.gz /usr/local

#添加环境变量
ENV JAVA_HOME /usr/local/jdk1..0_65
ENV CLASSPATH $JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
ENV CATALINA_HOME /usr/local/apache-tomcat-8.5.
ENV PATH $PATH:$JAVA_HOME/bin:$CATALINA_HOME/bin
RUN java -version

#安装supervisor
RUN yum install -y epel-release;yum -y install supervisor
RUN mkdir -p /etc/supervisor/
COPY supervisord.conf /etc/supervisor/

#暴露 22和8080端口
EXPOSE  

#运行supervisord
CMD supervisord -c /etc/supervisor/supervisord.conf

(2)配置supervisord.conf

[root@node105 docker]# vi supervisord.conf 

[unix_http_server]
file=/var/run/supervisor/supervisor.sock ; (the path to the socket file)

[supervisord]
logfile=/var/run/supervisor/supervisord.log ; (main log file;default $CWD/supervisord.log)
logfile_maxbytes=50MB        ; (max main logfile bytes b4 rotation;default 50MB)
logfile_backups=           ; (num of main logfile rotation backups;default )
loglevel=info                ; (log level;default info; others: debug,warn,trace)
pidfile=/var/run/supervisor/supervisord.pid ; (supervisord pidfile;default supervisord.pid)
nodaemon=true               ; (start in foreground if true;default false)
minfds=                  ; (min. avail startup file descriptors;default )
minprocs=                 ; (min. avail process descriptors;default )

[rpcinterface:supervisor]
supervisor.rpcinterface_factory = supervisor.rpcinterface:make_main_rpcinterface

[supervisorctl]
serverurl=unix:///var/run/supervisor/supervisor.sock ; use a unix:// URL  for a unix socket

[program:sshd]
command=/usr/sbin/sshd -D

[program:tomcat]
command=/usr/local/apache-tomcat-8.5./bin/catalina.sh run

注意：

在这里分号;是注释符号
serverurl=unix:///var/run/supervisor/supervisor.sock ： 这个建议不要修改
nodaemon=true ： 设置为true
command=/usr/local/apache-tomcat-8.5.45/bin/catalina.sh run ：这个必须这样写（supervisor管理tomcat必须这样启动，其他方式好像都有问题）

[root@node105 docker]# pwd
/usr/local/docker
[root@node105 docker]# ll
total
-rw-r--r--.  root root    Aug  : apache-tomcat-8.5..tar.gz
-rw-r--r--.  root root       Aug  : Dockerfile
-rw-r--r--.  root root  Aug  : jdk-8u65-linux-x64.tar.gz
-rw-r--r--.  root root       Aug  : supervisord.conf
[root@node105 docker]#

(3)创建镜像

[root@node105 docker]# docker build -t centos-ssh-tomcat:v1 .
[root@node105 docker]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
centos-ssh-tomcat   v1                  410de61dd6e6         seconds ago      852MB
centos                                 67fa590cfc1c         days ago          202MB

(4)运行容器

[root@node105 docker]# docker run -d --name ssh-tomcat --restart=always -p : -p : centos-ssh-tomcat:v1
29e39686f8787e993f2f327983f26c3fefa1bacc1eeb0f261badb15f718a8dd7

(5)验证
#ssh

#ssh
[root@node105 docker]# ssh localhost -p
The authenticity of host '[localhost]:4426 ([::1]:4426)' can't be established.
RSA key fingerprint is SHA256:cvH5wwrGfYnd/vbchFrrxycoZ7IkftRjJZSNsxzxIzc.
RSA key fingerprint is MD5:be::5a:f3:::1c:b4:f5:c5:3d:b7::::.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '[localhost]:4426' (RSA) to the list of known hosts.
root@localhost's password:
[root@c1fce40e19f9 etc]# ps -ef
UID        PID  PPID  C STIME TTY          TIME CMD
root                 : ?        :: /usr/bin/python /usr/bin/supervisord -c /etc/supervisor/supervisord.conf
root                 : ?        :: /usr/sbin/sshd -D
root                 : ?        :: sshd: root@pts/
root                : pts/    :: -bash
root               : pts/    :: ps -ef
[root@c1fce40e19f9 etc]# supervisorctl status
sshd                             RUNNING   pid , uptime ::
tomcat                           RUNNING   pid , uptime ::
[root@c1fce40e19f9 etc]# exit
logout
Connection to localhost closed.
[root@node105 docker]#

#tomcat

参考：

docker之使用supervisor管理多个进程 

centos7安装supervisor详细教程