docker镜像构建企业级示例
华子目录
- 示例（在centos容器中源码编译nginx（单介构建））
- 包准备
- 为`centos容器`提供`网络源`
- 添加`企业7`的`ISO文件`
- 提交为新的centos镜像
- 编写dockerfile文件
- 构建镜像
- 如何优化自己构建的镜像大小
- 多介构建
- ldd命令
- 基本用法
- 示例
- 镜像优化方案
示例（在centos容器中源码编译nginx（单介构建））
单介构建：只有一个from指令
包准备
-
上传
镜像centos-7.tar.gz -
导入
centos7镜像
[root@docker-node1 ~]# docker load -i centos-7.tar.gz
- 上传
源码包nginx-1.26.1.tar.gz - 将
nginx源码包放到上下文路径下
[root@docker-node1 ~]# cp nginx-1.26.1.tar.gz docker/
[root@docker-node1 ~]# cd docker/
[root@docker-node1 docker]# ls
nginx-1.26.1.tar.gz
为centos容器提供网络源
- 宿主机光盘中的包作为容器的yum网络源
[root@docker-node1 ~]# yum install httpd -y
[root@docker-node1 ~]# vim /etc/httpd/conf/httpd.conf
添加企业7的ISO文件
[root@docker-node1 ~]# mkdir /var/www/html/rhel7[root@docker-node1 ~]# mount /dev/sr
sr0 sr1[root@docker-node1 ~]# mount /dev/sr1 /var/www/html/rhel7/
[root@docker-node1 ~]# systemctl restart httpd
[root@docker-node1 ~]# ifconfig
- 运行
centos7镜像，容器名为centos
[root@docker-node1 ~]# docker run -d --name centos centos:7 sleep 10000
- 查看
centos容器的详细信息
[root@docker-node1 ~]# docker inspect centos
- 我们发现
宿主机和centos容器的网络是通的
[root@docker-node1 ~]# ping 172.17.0.2
PING 172.17.0.2 (172.17.0.2) 56(84) 比特的数据。
64 比特，来自 172.17.0.2: icmp_seq=1 ttl=64 时间=0.341 毫秒
64 比特，来自 172.17.0.2: icmp_seq=2 ttl=64 时间=0.156 毫秒
64 比特，来自 172.17.0.2: icmp_seq=3 ttl=64 时间=0.070 毫秒
- 进入
centos容器，添加yum源
[root@docker-node1 ~]# docker exec -it centos /bin/sh
sh-4.2# cd /etc/yum.repos.d/
sh-4.2# rm -rf *
sh-4.2# vi centos7.repo
[rhel7]
name=rhel7
baseurl=http://172.17.0.1:8080/rhel7/
gpgcheck=0
sh-4.2# #ctrl+p+q退出不停止容器
[root@docker-node1 ~]#
提交为新的centos镜像
[root@docker-node1 ~]# docker commit -a "huazi" -m "add yum repo" centos centos:repo
[root@docker-node1 ~]# docker images centos:repo
REPOSITORY TAG IMAGE ID CREATED SIZE
centos repo c618983b610f About a minute ago 204MB[root@docker-node1 ~]# docker history centos:repo
IMAGE CREATED CREATED BY SIZE COMMENT
c618983b610f 44 seconds ago sleep 10000 72B add yum repo
eeb6ee3f44bd 3 years ago /bin/sh -c #(nop) CMD ["/bin/bash"] 0B
<missing> 3 years ago /bin/sh -c #(nop) LABEL org.label-schema.sc… 0B
<missing> 3 years ago /bin/sh -c #(nop) ADD file:b3ebbe8bd304723d4… 204MB
编写dockerfile文件
[root@docker-node1 ~]# cd docker
[root@docker-node1 docker]# vim dockerfile
FROM centos:repo
LABEL Mail=huazi@huazi.org
ADD nginx-1.26.1.tar.gz /mnt
WORKDIR /mnt/nginx-1.26.1
RUN yum install gcc make pcre-devel openssl-devel -y
RUN ./configure --prefix=/usr/local/nginx --with-http_ssl_module --with-http_stub_status_module
RUN make
RUN make install
EXPOSE 80 443
VOLUME ["/usr/local/nginx/html"]
CMD ["/usr/local/nginx/sbin/nginx","-g","daemon off"][root@docker-node1 docker]# ls
dockerfile nginx-1.26.1.tar.gz
构建镜像
[root@docker-node1 docker]# docker build -t nginx:centos7 .
[root@docker-node1 docker]# docker history nginx:centos7
IMAGE CREATED CREATED BY SIZE COMMENT
939f29314f9a About a minute ago CMD ["/usr/local/nginx/sbin/nginx" "-g" "dae… 0B buildkit.dockerfile.v0
<missing> About a minute ago VOLUME [/usr/local/nginx/html] 0B buildkit.dockerfile.v0
<missing> About a minute ago EXPOSE map[443/tcp:{} 80/tcp:{}] 0B buildkit.dockerfile.v0
<missing> About a minute ago RUN /bin/sh -c make install # buildkit 6.11MB buildkit.dockerfile.v0
<missing> About a minute ago RUN /bin/sh -c make # buildkit 20.6MB buildkit.dockerfile.v0
<missing> About a minute ago RUN /bin/sh -c ./configure --prefix=/usr/loc… 78.9kB buildkit.dockerfile.v0
<missing> About a minute ago RUN /bin/sh -c yum install gcc make pcre-dev… 118MB buildkit.dockerfile.v0
<missing> About a minute ago WORKDIR /mnt/nginx-1.26.1 0B buildkit.dockerfile.v0
<missing> About a minute ago ADD nginx-1.26.1.tar.gz /mnt # buildkit 7.35MB buildkit.dockerfile.v0
<missing> About a minute ago LABEL Mail=huazi@huazi.org 0B buildkit.dockerfile.v0
<missing> About a minute ago /bin/sh 68B add centos7.repo
<missing> 3 years ago /bin/sh -c #(nop) CMD ["/bin/bash"] 0B
<missing> 3 years ago /bin/sh -c #(nop) LABEL org.label-schema.sc… 0B
<missing> 3 years ago /bin/sh -c #(nop) ADD file:b3ebbe8bd304723d4… 204MB
[root@docker-node1 docker]# docker images nginx:centos7
REPOSITORY TAG IMAGE ID CREATED SIZE
nginx centos7 939f29314f9a About a minute ago 356MB
- 我们发现构建出来的
镜像大小为356MB
如何优化自己构建的镜像大小
- 因为
一个指令为一层，所以我们可以减少层数，来优化镜像大小
[root@docker-node1 docker]# vim dockerfile
FROM centos:repo
LABEL Mail=huazi@huazi.org
ADD nginx-1.26.1.tar.gz /mnt
WORKDIR /mnt/nginx-1.26.1
RUN yum install gcc make pcre-devel openssl-devel -y && ./configure --prefix=/usr/local/nginx --with-http_ssl_module --with-http_stub_status_module && make && make install && rm -rf /mnt/nginx-1.26.1 && yum clean all
EXPOSE 80 443
VOLUME ["/usr/local/nginx/html"]
CMD ["/usr/local/nginx/sbin/nginx","-g","daemon off"]
[root@docker-node1 docker]# docker build -t nginx2:centos7 .
[root@docker-node1 docker]# docker images nginx2:centos7
REPOSITORY TAG IMAGE ID CREATED SIZE
nginx2 centos7 643164382b66 41 seconds ago 292MB
- 我们发现镜像大小
变小了
多介构建
- 一个
dockerfile中有多个from指令
FROM centos:repo AS build #AS标记为build阶段
LABEL Mail=huazi@huazi.org
ADD nginx-1.26.1.tar.gz /mnt
WORKDIR /mnt/nginx-1.26.1
RUN yum install gcc make pcre-devel openssl-devel -y && ./configure --prefix=/usr/local/nginx --with-http_ssl_module --with-http_stub_status_module && make && make install && rm -rf /mnt/nginx-1.26.1 && yum clean allFROM centos:repo
LABEL mail=huazi@huazi.org
COPY --from=build /usr/local/nginx /usr/local/nginx #将build阶段中的/usr/local/nginx复制到当前阶段中的/usr/local/nginx
EXPOSE 80 443
VOLUME ["/usr/local/nginx/html"]
CMD ["/usr/local/nginx/sbin/nginx","-g","daemon off"]
[root@docker-node1 docker]# docker build -t nginx3:centos7 .
[root@docker-node1 docker]# docker images nginx3:centos7
REPOSITORY TAG IMAGE ID CREATED SIZE
nginx3 centos7 27a5c3dd15c1 14 seconds ago 210MB
- 我们发现镜像大小
变小了
ldd命令
当你对一个可执行文件或共享库使用ldd命令时，它会列出该文件所依赖的所有共享库，以及这些共享库在文件系统中的路径
基本用法
ldd <可执行文件或共享库>
示例
假设你有一个名为my_program的可执行文件，你可以使用以下命令来查看它的共享库依赖关系：
ldd my_program
输出可能类似于：
linux-vdso.so.1 (0x00007fffdc9d7000)libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f8a6c61c000)libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f8a6c22b000)/lib64/ld-linux-x86-64.so.2 (0x00007f8a6c91b000)
这里，my_program依赖于libm.so.6（数学库）、libc.so.6（C标准库）和ld-linux-x86-64.so.2（动态链接器/加载器）
镜像优化方案
- 选择
最精简的基础镜像 - 减少
镜像的层数 清理镜像构建的中间产物