上面两篇文章，详细说明了使用dockerfile创建镜像的原理
《Docker Dockerfile指令说明（十二）》
《Docker Dockerfile创建镜像说明（十三）》
本片为实际操作案例。基于centos创建nginx镜像
1. 下载镜像
docker pull centos
2. 创建文件目录
mkdir -p /www/nginx
3. 创建并编辑Dockerfile文件
cd /www/nginx
vim Dockerfile
添加在Dockerfile以下内容
FROM centos:latest # 选择centos镜像
MAINTAINER by dongzao # 维护信息人dongzao
RUN yum install -y wget pcre-devel net-tools gcc zlib zlib-devel make openssl-devel # 安装nginx依赖
RUN useradd -M -u 40 -s /sbin/nologin nginx # 创建nginx用户
RUN wget http://nginx.org/download/nginx-1.16.1.tar.gz # 下载nginx文件
RUN tar zxvf nginx-1.16.1.tar.gz
WORKDIR nginx-1.16.1 # 设置工作目录
RUN ./configure --prefix=/usr/local/nginx --user=nginx --group=nginx --with-file-aio --with-http_stub_status_module --with-http_gzip_static_module --with-http_flv_module --with-http_ssl_module --with-http_realip_module&& make && make install # 编译安装nginx
RUN ln -s /usr/local/nginx/sbin/* /usr/local/sbin/ # 启动Nginx服务
RUN /usr/local/nginx/sbin/nginx
EXPOSE 80 # 开放http端口
EXPOSE 443 # 开放https端口
RUN echo "daemon off;">>/usr/local/nginx/conf/nginx.conf # 关闭守护进程
WORKDIR /opt/nginx # 创建目录/www/nginx
ADD run.sh /run.sh # 将宿主机中的run.sh添加到容器中 开机自启
RUN chmod 755 /run.sh # 开机自启
CMD ["/run.sh"] # 开机自启
注意：为什么要关闭守护进程（daemon off）
docker 容器默认会把容器内部第一个进程，也就是pid=1的程序作为docker容器是否正在运行的依据，如果docker 容器pid挂了，那么docker容器便会直接退出
Docker未执行自定义的CMD之前，nginx的pid是1，执行到CMD之后，nginx就在后台运行，bash或sh脚本的pid变成了1。如果启动命令单纯是以后台守护(daemon)模式启动nginx，那么启动命令会立即结束，容器也会立即结束。
4. 编辑 run.sh
run.sh作用在于nginx开机自启
vim run.sh
!/bin/bash
/usr/local/nginx/sbin/nginx
5. 创建镜像
docker build -t mynginx:centos .
不要忘记“.”,这个小点！！！
[root@docker nginx]# docker build -t mynginx .
Sending build context to Docker daemon 4.096kB
Step 1/17 : FROM centos
---> 470671670cac
Step 2/17 : MAINTAINER by dongzao
---> Running in 2e96eba377dd
Removing intermediate container 2e96eba377dd
---> 88a28035b432
Step 3/17 : RUN yum install -y wget pcre-devel net-tools gcc zlib zlib-devel make openssl-devel
---> Running in 71db754b44d1
CentOS-8 - AppStream 2.7 MB/s | 6.4 MB 00:02
CentOS-8 - Base 78 kB/s | 5.0 MB 01:04
CentOS-8 - Extras 3.3 kB/s | 2.1 kB 00:00
Package zlib-1.2.11-10.el8.x86_64 is already installed.
Dependencies resolved.
----省略-----
Installed:
gcc-8.3.1-4.5.el8.x86_64
wget-1.19.5-8.el8_1.1.x86_64
make-1:4.2.1-9.el8.x86_64
net-tools-2.0-0.51.20160912git.el8.x86_64
openssl-devel-1:1.1.1c-2.el8.x86_64
pcre-devel-8.42-4.el8.x86_64
zlib-devel-1.2.11-10.el8.x86_64
cpp-8.3.1-4.5.el8.x86_64
isl-0.16.1-6.el8.x86_64
libmpc-1.0.2-9.el8.x86_64
glibc-devel-2.28-72.el8.x86_64
glibc-headers-2.28-72.el8.x86_64
kernel-headers-4.18.0-147.5.1.el8_1.x86_64
keyutils-libs-devel-1.5.10-6.el8.x86_64
krb5-devel-1.17-9.el8.x86_64
libcom_err-devel-1.44.6-3.el8.x86_64
libgomp-8.3.1-4.5.el8.x86_64
libkadm5-1.17-9.el8.x86_64
libpkgconf-1.4.2-1.el8.x86_64
libpsl-0.20.2-5.el8.x86_64
libselinux-devel-2.9-2.1.el8.x86_64
libsepol-devel-2.9-1.el8.x86_64
libverto-devel-0.3.0-5.el8.x86_64
libxcrypt-devel-4.1.1-4.el8.x86_64
pcre-cpp-8.42-4.el8.x86_64
pcre-utf16-8.42-4.el8.x86_64
pcre-utf32-8.42-4.el8.x86_64
pcre2-devel-10.32-1.el8.x86_64
pcre2-utf16-10.32-1.el8.x86_64
pcre2-utf32-10.32-1.el8.x86_64
pkgconf-1.4.2-1.el8.x86_64
pkgconf-m4-1.4.2-1.el8.noarch
pkgconf-pkg-config-1.4.2-1.el8.x86_64
publicsuffix-list-dafsa-20180723-1.el8.noarch
Complete!
Removing intermediate container 71db754b44d1
---> c17212d1b24b
Step 4/17 : RUN useradd -M -u 40 -s /sbin/nologin nginx
---> Running in 79767e27e837
Removing intermediate container 79767e27e837
---> b713872c355b
Step 5/17 : RUN wget http://nginx.org/download/nginx-1.16.1.tar.gz
---> Running in 06d359a6e68e
--2020-02-19 15:25:37-- http://nginx.org/download/nginx-1.16.1.tar.gz
Resolving nginx.org (nginx.org)... 62.210.92.35, 95.211.80.227, 2001:1af8:4060:a004:21::e3
Connecting to nginx.org (nginx.org)|62.210.92.35|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 1032630 (1008K) [application/octet-stream]
Saving to: 'nginx-1.16.1.tar.gz'
----省略-----
Removing intermediate container 643c99457706
---> 2f472deb6299
Step 7/17 : WORKDIR nginx-1.16.1
---> Running in 3b885d76a564
Removing intermediate container 3b885d76a564
---> 96c21a679350
Step 8/17 : RUN ./configure --prefix=/usr/local/nginx --user=nginx --group=nginx --with-file-aio --with-http_stub_status_module --with-http_gzip_static_module --with-http_flv_module --with-http_ssl_module --with-http_realip_module&& make && make install
---> Running in 9cb0f3112934
checking for OS
+ Linux 3.10.0-1062.9.1.el7.x86_64 x86_64
----省略-----
creating objs/Makefile
Configuration summary
+ using system PCRE library
+ using system OpenSSL library
+ using system zlib library
nginx path prefix: "/usr/local/nginx"
nginx binary file: "/usr/local/nginx/sbin/nginx"
nginx modules path: "/usr/local/nginx/modules"
nginx configuration prefix: "/usr/local/nginx/conf"
nginx configuration file: "/usr/local/nginx/conf/nginx.conf"
nginx pid file: "/usr/local/nginx/logs/nginx.pid"
nginx error log file: "/usr/local/nginx/logs/error.log"
nginx http access log file: "/usr/local/nginx/logs/access.log"
nginx http client request body temporary files: "client_body_temp"
nginx http proxy temporary files: "proxy_temp"
nginx http fastcgi temporary files: "fastcgi_temp"
nginx http uwsgi temporary files: "uwsgi_temp"
nginx http scgi temporary files: "scgi_temp"
make -f objs/Makefile
make[1]: Entering directory '/nginx-1.16.1'
cc -c -pipe -O -W -Wall -Wpointer-arith -Wno-unused-parameter -Werror -g -I src/core -I src/event -I src/event/modules -I src/os/unix -I objs \
-o objs/src/core/nginx.o \
src/core/nginx.c
----省略-----
cc -c -pipe -O -W -Wall -Wpointer-arith -Wno-unused-parameter -Werror -g -I src/core -I src/event -I src/event/modules -I src/os/unix -I objs \
-o objs/ngx_modules.o \
objs/ngx_modules.c
cc -o objs/nginx \
objs/src/core/nginx.o \
objs/src/core/ngx_log.o \
----省略-----
objs/src/http/modules/ngx_http_stub_status_module.o \
objs/ngx_modules.o \
-ldl -lpthread -lcrypt -lpcre -lssl -lcrypto -ldl -lpthread -lz \
-Wl,-E
sed -e "s|%%PREFIX%%|/usr/local/nginx|" \
-e "s|%%PID_PATH%%|/usr/local/nginx/logs/nginx.pid|" \
-e "s|%%CONF_PATH%%|/usr/local/nginx/conf/nginx.conf|" \
-e "s|%%ERROR_LOG_PATH%%|/usr/local/nginx/logs/error.log|" \
< man/nginx.8 > objs/nginx.8
make[1]: Leaving directory '/nginx-1.16.1'
make -f objs/Makefile install
make[1]: Entering directory '/nginx-1.16.1'
test -d '/usr/local/nginx' || mkdir -p '/usr/local/nginx'
----省略-----
test -d '/usr/local/nginx/logs' \
|| mkdir -p '/usr/local/nginx/logs'
make[1]: Leaving directory '/nginx-1.16.1'
Removing intermediate container 9cb0f3112934
---> b7454ec1a85d
Step 9/17 : RUN ln -s /usr/local/nginx/sbin/* /usr/local/sbin/
---> Running in 97cb999013a3
Removing intermediate container 97cb999013a3
---> 2a3b9eb0e1b8
Step 10/17 : RUN /usr/local/nginx/sbin/nginx
---> Running in f7f14b1ca65b
Removing intermediate container f7f14b1ca65b
---> bc9e0894230a
Step 11/17 : EXPOSE 80
---> Running in 75fbe5511c7b
Removing intermediate container 75fbe5511c7b
---> f404437c2bf0
Step 12/17 : EXPOSE 443
---> Running in dec91ffa66e2
Removing intermediate container dec91ffa66e2
---> 078f8188b385
Step 13/17 : RUN echo "daemon off;">>/usr/local/nginx/conf/nginx.conf
---> Running in dcbdb33988b8
Removing intermediate container dcbdb33988b8
---> 9578bf8f1806
Step 14/17 : WORKDIR /opt/nginx
---> Running in 39656b0357a9
Removing intermediate container 39656b0357a9
---> a62527b43a94
Step 15/17 : ADD run.sh /run.sh
---> e209bf6bbd1b
Step 16/17 : RUN chmod 755 /run.sh
---> Running in e338aa79d47f
Removing intermediate container e338aa79d47f
---> aef4c73c8b86
Step 17/17 : CMD ["/run.sh"]
---> Running in 78f0456548cd
Removing intermediate container 78f0456548cd
---> 0b775c9bceaf
Successfully built 0b775c9bceaf
Successfully tagged mynginx:latest
6. 启动容器进行测试
docker run -itd -p 80:80 --name nginx_1 nginx:centos # 启动容器，-p 指定宿主机80端口映射容器中nginx服务80端口
docker ps //查看运行的容器
7. 进入容器
docker exec -it nginx_1 bash
8. 验证网页
宿主IP地址：192.168.10.148，直接访问即可！
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