Dockerfile语法：

MAINTAINER:镜像创建者信息
EXPOSE:开放的端口
ENV:设置变量
WORKDIR:定义容器默认工作目录，相当于cd到某个目录
CMD:容器启动时执行的命令，仅可以有一条CMD

1先在容器内手动安装阿帕奇：

#1进入容器
[root@web01 ~]#docker run -it mycentos8:v20211229
#2安装阿帕奇
[root@e81ffc0059aa /]# yum -y install httpd
#3查看启动文件看看阿帕奇是如何启动的
[root@e81ffc0059aa ~]# cat /lib/systemd/system/httpd.service

[Unit]
Description=The Apache HTTP Server
Wants=httpd-init.service
After=network.target remote-fs.target nss-lookup.target httpd-init.service
Documentation=man:httpd.service(8)

[Service]
Type=notify
#环境变量
Environment=LANG=C
#执行启动命令
ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND
ExecReload=/usr/sbin/httpd $OPTIONS -k graceful
# Send SIGWINCH for graceful stop
KillSignal=SIGWINCH
KillMode=mixed
PrivateTmp=true

[Install]
WantedBy=multi-user.target
[root@e81ffc0059aa ~]#

4启动阿帕奇
[root@e81ffc0059aa ~]# LANG=C
[root@e81ffc0059aa ~]# /usr/sbin/httpd $OPTIONS -k graceful
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 message
httpd not running, trying to start

[root@e81ffc0059aa ~]# /usr/sbin/httpd $OPTIONS -DFOREGROUND
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 message
httpd (pid 73) already running

#查看执行历史
[root@e81ffc0059aa ~]# history
   19  yum -y install httpd
   20  systemctl start httpd
   21  pstree -p
   27  cat /lib/systemd/system/httpd.service
   28  LANG=C
   30  /usr/sbin/httpd $OPTIONS -DFOREGROUND
[root@e81ffc0059aa ~]#

2编写dockerfile：

[root@web01 ~]#mkdir bb
[root@web01 ~]#cd bb
[root@web01 ~/bb]#touch Dockerfile
[root@web01 ~/bb]#vim Dockerfile 
[root@web01 ~/bb]#cat Dockerfile 
FROM mycentos8:v20211229
RUN yum -y install httpd
ENV LANG=C
#指定开放的端口
EXPOSE 80 443
#设置默认的工作目录
WORKDIR /var/www/html
#拷贝文件到指定目录
ADD index.html /var/www/html/index.html
#cmd特定语法格式例如ls -la: CMD ["ls","-l","-a"]
CMD ["/usr/sbin/httpd", "-DFOREGROUND"]

3创建html文件

[root@web01 ~/bb]#vim index.html
[root@web01 ~/bb]#pwd
/root/bb

4执行dockerfile创建阿帕奇服务镜像

[root@web01 ~/bb]#docker build -t mycentos8:httpd .

5基于镜像构建容器：

[root@web01 ~/bb]#docker run --name httpd -d -p 80:80 mycentos8:httpd

6验证：

#查看容器
[root@web01 ~/bb]#docker ps
CONTAINER ID   IMAGE             COMMAND                  CREATED         STATUS         PORTS                                        NAMES
f8361cb098b0   mycentos8:httpd   "/usr/sbin/httpd -DF…"   5 seconds ago   Up 4 seconds   0.0.0.0:80->80/tcp, :::80->80/tcp, 443/tcp   httpd
#查看容器详细信息
[root@web01 ~/bb]#docker inspect f8361cb098b0  
 "Gateway": "172.17.0.1",
 "IPAddress": "172.17.0.2",
#模拟浏览器访问 
[root@web01 ~/bb]#curl 172.17.0.2
hello world!