DockerFile
我们要研究自己如何做一个镜像，而且我们写的微服务项目以及springboot打包上云部署，Docker就是 最方便的。
微服务打包成镜像，任何装了Docker的地方，都可以下载使用，极其的方便。
流程：开发应用=>DockerFile=>打包为镜像=>上传到仓库（私有仓库，公有仓库）=> 下载镜像 => 启动 运行。
还可以方便移植！
什么是DockerFile
dockerfile是用来构建Docker镜像的构建文件，是由一系列命令和参数构成的脚本。 构建步骤：
- 编写DockerFile文件
- docker build 构建镜像
- docker run
- docker push 发布镜像（DockerHub 、阿里云镜像仓库）
dockerfile文件我们刚才已经编写过了一次，这里我们继续使用 centos 来看！
地址：https://hub.docker.com/_/centos
FROM scratch
ADD centos-7-x86_64-docker.tar.xz /
LABEL \
org.label-schema.schema-version="1.0" \
org.label-schema.name="CentOS Base Image" \
org.label-schema.vendor="CentOS" \
org.label-schema.license="GPLv2" \
org.label-schema.build-date="20200504" \
org.opencontainers.image.title="CentOS Base Image" \
org.opencontainers.image.vendor="CentOS" \
org.opencontainers.image.licenses="GPL-2.0-only" \
org.opencontainers.image.created="2020-05-04 00:00:00+01:00"
CMD ["/bin/bash"]DockerFile构建过程
基础知识
- 每条保留字指令都必须为大写字母且后面要跟随至少一个参数
- 指令按照从上到下，顺序执行
- # 表示注释
- 每条指令都会创建一个新的镜像层，并对镜像进行提交
流程
- docker从基础镜像运行一个容器
- 执行一条指令并对容器做出修改
- 执行类似 docker commit 的操作提交一个新的镜像层
- Docker再基于刚提交的镜像运行一个新容器
- 执行dockerfile中的下一条指令直到所有指令都执行完成！
说明
从应用软件的角度来看，DockerFile，docker镜像与docker容器分别代表软件的三个不同阶段。
- DockerFile 是软件的原材料 （代码）
- Docker 镜像则是软件的交付品 （.apk）
- Docker 容器则是软件的运行状态 （客户下载安装执行）
DockerFile 面向开发，Docker镜像成为交付标准，Docker容器则涉及部署与运维，三者缺一不可
DockerFile：需要定义一个DockerFile，DockerFile定义了进程需要的一切东西。DockerFile涉及的内容 包括执行代码或者是文件、环境变量、依赖包、运行时环境、动态链接库、操作系统的发行版、服务进 程和内核进程（当引用进行需要和系统服务和内核进程打交道，这时需要考虑如何设计 namespace的权 限控制）等等。
Docker镜像：在DockerFile 定义了一个文件之后，Docker build 时会产生一个Docker镜像，当运行 Docker 镜像时，会真正开始提供服务；
Docker容器：容器是直接提供服务的。
DockerFile指令
关键字
FROM # 基础镜像，当前新镜像是基于哪个镜像的
MAINTAINER # 镜像维护者的姓名混合邮箱地址
RUN # 容器构建时需要运行的命令
EXPOSE # 当前容器对外保留出的端口
WORKDIR # 指定在创建容器后，终端默认登录的进来工作目录，一个落脚点
ENV # 用来在构建镜像过程中设置环境变量
ADD # 将宿主机目录下的文件拷贝进镜像且 ADD 命令会自动处理 URL 和解压 tar 压缩包
COPY # 类似ADD，拷贝文件和目录到镜像中！
VOLUME # 容器数据卷，用于数据保存和持久化工作
CMD # 指定一个容器启动时要运行的命令，dockerFile 中可以有多个 CMD 指令，但只有最后一个生效！
ENTRYPOINT # 指定一个容器启动时要运行的命令！和CMD一样
ONBUILD # 当构建一个被继承的 DockerFile 时运行命令，父镜像在被子镜像继承后，父镜像的 ONBUILD 被触发
实战：构建自己的CentOs
Docker Hub 中99% 的镜像都是通过在base镜像（Scratch）中安装和配置需要的软件构建出来的
自定义一个 centos
编写DockerFile
查看下官方默认的CentOS的情况：
目的：使我们自己的镜像具备如下：登陆后的默认路径、vim编辑器、查看网络配置ifconfig支持
准备编写DockerFlie文件
[root@xiaoyequ home]# mkdir dockerfile
[root@xiaoyequ home]# ls
dockerfile docker-test-volume
[root@xiaoyequ home]# cd dockerfile
[root@xiaoyequ dockerfile]# vim mydockerfile-centos
[root@xiaoyequ dockerfile]# cat mydockerfile-centos
FROM centos
MAINTAINER xiaoyequ<[email protected]>
ENV MYPATH /usr/local
WORKDIR $MYPATH
RUN yum -y install vim
RUN yum -y install net-tools
EXPOSE 80
CMD echo $MYPATH
CMD echo "----------end--------"
CMD /bin/bash
构建
docker build -f dockerfile地址 -t 新镜像名字:TAG .
会看到 docker build 命令最后有一个 . . 表示当前目录****
[root@xiaoyequ dockerfile]# docker build -f mydockerfile-centos -t mycentos:0.1 .
Sending build context to Docker daemon 2.048kB
Step 1/10 : FROM centos
---> 470671670cac
Step 2/10 : MAINTAINER xiaoyequ<[email protected]>
---> Running in c97d0a352bc2
Removing intermediate container c97d0a352bc2
---> c56092384a02
Step 3/10 : ENV MYPATH /usr/local
---> Running in ff73ff482805
Removing intermediate container ff73ff482805
---> 3a3934c9346a
Step 4/10 : WORKDIR $MYPATH
---> Running in 80b1aeaa7b48
Removing intermediate container 80b1aeaa7b48
---> 44ef2034ac3b
Step 5/10 : RUN yum -y install vim
---> Running in 8515e9f531e1
CentOS-8 - AppStream 317 kB/s | 7.0 MB 00:22
CentOS-8 - Base 873 kB/s | 2.2 MB 00:02
CentOS-8 - Extras 8.1 kB/s | 6.7 kB 00:00
Dependencies resolved.
================================================================================
Package Arch Version Repository Size
================================================================================
Installing:
vim-enhanced x86_64 2:8.0.1763-13.el8 AppStream 1.4 M
Installing dependencies:
gpm-libs x86_64 1.20.7-15.el8 AppStream 39 k
vim-common x86_64 2:8.0.1763-13.el8 AppStream 6.3 M
vim-filesystem noarch 2:8.0.1763-13.el8 AppStream 48 k
which x86_64 2.21-10.el8 BaseOS 49 k
Transaction Summary
================================================================================
Install 5 Packages
Total download size: 7.8 M
Installed size: 31 M
Downloading Packages:
(1/5): gpm-libs-1.20.7-15.el8.x86_64.rpm 210 kB/s | 39 kB 00:00
(2/5): vim-filesystem-8.0.1763-13.el8.noarch.rp 147 kB/s | 48 kB 00:00
(3/5): which-2.21-10.el8.x86_64.rpm 223 kB/s | 49 kB 00:00
(4/5): vim-enhanced-8.0.1763-13.el8.x86_64.rpm 542 kB/s | 1.4 MB 00:02
(5/5): vim-common-8.0.1763-13.el8.x86_64.rpm 551 kB/s | 6.3 MB 00:11
--------------------------------------------------------------------------------
Total 637 kB/s | 7.8 MB 00:12
warning: /var/cache/dnf/AppStream-02e86d1c976ab532/packages/gpm-libs-1.20.7-15.el8.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID 8483c65d: NOKEY
CentOS-8 - AppStream 1.6 MB/s | 1.6 kB 00:00
Importing GPG key 0x8483C65D:
Userid : "CentOS (CentOS Official Signing Key) "
Fingerprint: 99DB 70FA E1D7 CE22 7FB6 4882 05B5 55B3 8483 C65D
From : /etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial
Key imported successfully
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
Preparing : 1/1
Installing : which-2.21-10.el8.x86_64 1/5
Installing : vim-filesystem-2:8.0.1763-13.el8.noarch 2/5
Installing : vim-common-2:8.0.1763-13.el8.x86_64 3/5
Installing : gpm-libs-1.20.7-15.el8.x86_64 4/5
Running scriptlet: gpm-libs-1.20.7-15.el8.x86_64 4/5
Installing : vim-enhanced-2:8.0.1763-13.el8.x86_64 5/5
Running scriptlet: vim-enhanced-2:8.0.1763-13.el8.x86_64 5/5
Running scriptlet: vim-common-2:8.0.1763-13.el8.x86_64 5/5
Verifying : gpm-libs-1.20.7-15.el8.x86_64 1/5
Verifying : vim-common-2:8.0.1763-13.el8.x86_64 2/5
Verifying : vim-enhanced-2:8.0.1763-13.el8.x86_64 3/5
Verifying : vim-filesystem-2:8.0.1763-13.el8.noarch 4/5
Verifying : which-2.21-10.el8.x86_64 5/5
Installed:
vim-enhanced-2:8.0.1763-13.el8.x86_64 gpm-libs-1.20.7-15.el8.x86_64
vim-common-2:8.0.1763-13.el8.x86_64 vim-filesystem-2:8.0.1763-13.el8.noarch
which-2.21-10.el8.x86_64
Complete!
Removing intermediate container 8515e9f531e1
---> 95b49a652fcf
Step 6/10 : RUN yum -y install net-tools
---> Running in 81e5c3e7ad4b
Last metadata expiration check: 0:00:21 ago on Mon Jun 15 13:39:27 2020.
Dependencies resolved.
================================================================================
Package Architecture Version Repository Size
================================================================================
Installing:
net-tools x86_64 2.0-0.51.20160912git.el8 BaseOS 323 k
Transaction Summary
================================================================================
Install 1 Package
Total download size: 323 k
Installed size: 1.0 M
Downloading Packages:
net-tools-2.0-0.51.20160912git.el8.x86_64.rpm 889 kB/s | 323 kB 00:00
--------------------------------------------------------------------------------
Total 377 kB/s | 323 kB 00:00
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
Preparing : 1/1
Installing : net-tools-2.0-0.51.20160912git.el8.x86_64 1/1
Running scriptlet: net-tools-2.0-0.51.20160912git.el8.x86_64 1/1
Verifying : net-tools-2.0-0.51.20160912git.el8.x86_64 1/1
Installed:
net-tools-2.0-0.51.20160912git.el8.x86_64
Complete!
Removing intermediate container 81e5c3e7ad4b
---> fe17a32549a5
Step 7/10 : EXPOSE 80
---> Running in 2808f77c4346
Removing intermediate container 2808f77c4346
---> c449a929e0e2
Step 8/10 : CMD echo $MYPATH
---> Running in ce2adef5c76c
Removing intermediate container ce2adef5c76c
---> 28288525952a
Step 9/10 : CMD echo "----------end--------"
---> Running in fa70e120126c
Removing intermediate container fa70e120126c
---> 68f2037e2ddf
Step 10/10 : CMD /bin/bash
---> Running in 9c21b869a3ad
Removing intermediate container 9c21b869a3ad
---> 0deef898a52e
Successfully built 0deef898a52e
Successfully tagged mycentos:0.1
运行
docker run -it 新镜像名字:TAG
docker run -it mycentos:0.1 
可以看到，我们自己的新镜像已经支持 vim、ifconfig的命令，扩展OK！
列出镜像地的变更历史
docker history 镜像名
docker history 0deef898a52e
CMD 和 ENTRYPOINT 的区别
两个命令都是指定一个容器启动时要运行的命令
CMD：Dockerfile 中可以有多个CMD 指令，但只有最后一个生效，CMD 会被 docker run 之后的参数 替换！
ENTRYPOINT： docker run 之后的参数会被当做参数传递给 ENTRYPOINT，之后形成新的命令组合！
CMD命令
构建dockerfile
[root@xiaoyequ home]# vim dockerfile-cmd-test
[root@xiaoyequ home]# cat dockerfile-cmd-test
FROM centos
CMD [ "ls", "-a" ]
build 镜像
[root@xiaoyequ home]# docker build -f dockerfile-cmd-test -t cmdtest .
Sending build context to Docker daemon 5.12kB
Step 1/2 : FROM centos
---> 470671670cac
Step 2/2 : CMD [ "ls", "-a" ]
---> Running in 3f0f8a4b3848
Removing intermediate container 3f0f8a4b3848
---> ad2fb09d1b81
Successfully built ad2fb09d1b81
Successfully tagged cmdtest:latest
执行
[root@xiaoyequ home]# docker run ad2fb09d1b81
.
..
.dockerenv
bin
dev
etc
home
lib
lib64
lost+found
media
mnt
opt
proc
root
run
sbin
srv
sys
tmp
usr
var
如果我们希望用 -l 列表展示信息，我们就需要加上 -l参数
[root@xiaoyequ home]# docker run cmdtest -l
docker: Error response from daemon: OCI runtime create failed: container_linux.go:349: starting container process caused "exec: \"-l\": executable file not found in $PATH": unknown.
ERRO[0000] error waiting for container: context canceled
- 问题：我们可以看到可执行文件找不到的报错，executable file not found。
- 之前我们说过，跟在镜像名后面的是 command，运行时会替换 CMD 的默认值。
- 因此这里的 -l 替换了原来的 CMD，而不是添加在原来的 ls -a 后面。而 -l 根本不是命令，所 以自然找不到。
- 那么如果我们希望加入 -l 这参数，我们就必须重新完整的输入这个命令：
docker run cmdtest ls -al
[root@xiaoyequ home]# docker run cmdtest ls -al total 56 drwxr-xr-x 1 root root 4096 Jun 16 12:56 . drwxr-xr-x 1 root root 4096 Jun 16 12:56 .. -rwxr-xr-x 1 root root 0 Jun 16 12:56 .dockerenv lrwxrwxrwx 1 root root 7 May 11 2019 bin -> usr/bin drwxr-xr-x 5 root root 340 Jun 16 12:56 dev drwxr-xr-x 1 root root 4096 Jun 16 12:56 etc drwxr-xr-x 2 root root 4096 May 11 2019 home lrwxrwxrwx 1 root root 7 May 11 2019 lib -> usr/lib lrwxrwxrwx 1 root root 9 May 11 2019 lib64 -> usr/lib64 drwx------ 2 root root 4096 Jan 13 21:48 lost+found drwxr-xr-x 2 root root 4096 May 11 2019 media drwxr-xr-x 2 root root 4096 May 11 2019 mnt drwxr-xr-x 2 root root 4096 May 11 2019 opt dr-xr-xr-x 97 root root 0 Jun 16 12:56 proc dr-xr-x--- 2 root root 4096 Jan 13 21:49 root drwxr-xr-x 11 root root 4096 Jan 13 21:49 run lrwxrwxrwx 1 root root 8 May 11 2019 sbin -> usr/sbin drwxr-xr-x 2 root root 4096 May 11 2019 srv dr-xr-xr-x 13 root root 0 Jun 14 13:03 sys drwxrwxrwt 7 root root 4096 Jan 13 21:49 tmp drwxr-xr-x 12 root root 4096 Jan 13 21:49 usr drwxr-xr-x 20 root root 4096 Jan 13 21:49 var
ENTRYPOINT命令
构建dockerfile
[root@xiaoyequ home]# vim dockerfile-entrypoint-test
[root@xiaoyequ home]# cat dockerfile-entrypoint-test
FROM centos
ENTRYPOINT [ "ls", "-a" ]build 镜像
[root@xiaoyequ home]# docker build -f dockerfile-entrypoint-test -t entrypointtest .
Sending build context to Docker daemon 6.144kB
Step 1/2 : FROM centos
---> 470671670cac
Step 2/2 : ENTRYPOINT [ "ls", "-a" ]
---> Running in 672fb009096a
Removing intermediate container 672fb009096a
---> 81aedb452f1c
Successfully built 81aedb452f1c
Successfully tagged entrypointtest:latest
执行
[root@xiaoyequ home]# docker run 81aedb452f1c
.
..
.dockerenv
bin
dev
etc
home
lib
lib64
lost+found
media
mnt
opt
proc
root
run
sbin
srv
sys
tmp
usr
var测试 -l 参数
[root@xiaoyequ home]# docker run entrypointtest -l
total 56
drwxr-xr-x 1 root root 4096 Jun 16 13:08 .
drwxr-xr-x 1 root root 4096 Jun 16 13:08 ..
-rwxr-xr-x 1 root root 0 Jun 16 13:08 .dockerenv
lrwxrwxrwx 1 root root 7 May 11 2019 bin -> usr/bin
drwxr-xr-x 5 root root 340 Jun 16 13:08 dev
drwxr-xr-x 1 root root 4096 Jun 16 13:08 etc
drwxr-xr-x 2 root root 4096 May 11 2019 home
lrwxrwxrwx 1 root root 7 May 11 2019 lib -> usr/lib
lrwxrwxrwx 1 root root 9 May 11 2019 lib64 -> usr/lib64
drwx------ 2 root root 4096 Jan 13 21:48 lost+found
drwxr-xr-x 2 root root 4096 May 11 2019 media
drwxr-xr-x 2 root root 4096 May 11 2019 mnt
drwxr-xr-x 2 root root 4096 May 11 2019 opt
dr-xr-xr-x 97 root root 0 Jun 16 13:08 proc
dr-xr-x--- 2 root root 4096 Jan 13 21:49 root
drwxr-xr-x 11 root root 4096 Jan 13 21:49 run
lrwxrwxrwx 1 root root 8 May 11 2019 sbin -> usr/sbin
drwxr-xr-x 2 root root 4096 May 11 2019 srv
dr-xr-xr-x 13 root root 0 Jun 14 13:03 sys
drwxrwxrwt 7 root root 4096 Jan 13 21:49 tmp
drwxr-xr-x 12 root root 4096 Jan 13 21:49 usr
drwxr-xr-x 20 root root 4096 Jan 13 21:49 var
发现可以直接使用，这里就是一种追加，我们可以明显的知道 CMD 和 ENTRYPOINT 的区别了
自定义镜像 tomcat
jdk1.8的命令下载方式：
wget --no-check-certificate --no-cookies --header "Cookie: oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/8u131-b11/d54c1d3a095b4ff2b6607d096fa80163/jdk-8u131-linux-x64.tar.gz在 /home/tomcat 目录下新建一个Dockerfile文件
FROM centos
MAINTAINER xiaoyequ<[email protected]>
#把宿主机当前上下文的read.txt拷贝到容器/usr/local/路径下
COPY read.txt /usr/local/cincontainer.txt
#把java与tomcat添加到容器中
ADD jdk-8u131-linux-x64.tar.gz /usr/local/
ADD apache-tomcat-9.0.36.tar.gz /usr/local/
#安装vim编辑器
RUN yum -y install vim
#设置工作访问时候的WORKDIR路径，登录落脚点
ENV MYPATH /usr/local
WORKDIR $MYPATH
#配置java与tomcat环境变量
ENV JAVA_HOME /usr/local/jdk1.8.0_131
ENV CLASSPATH $JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
ENV CATALINA_HOME /usr/local/apache-tomcat-9.0.36
ENV CATALINA_BASE /usr/local/apache-tomcat-9.0.36
ENV PATH $PATH:$JAVA_HOME/bin:$CATALINA_HOME/lib:$CATALINA_HOME/bin
#容器运行时监听的端口
EXPOSE 8080
#启动时运行tomcat
# ENTRYPOINT ["/usr/local/apache-tomcat-9.0.36/bin/startup.sh" ]
# CMD ["/usr/local/apache-tomcat-9.0.36/bin/catalina.sh","run"]
CMD /usr/local/apache-tomcat-9.0.36/bin/startup.sh && tail -F /usr/local/apache-tomcat-9.0.36/bin/logs/catalina.out
构建镜像
docker build -t diytomcat .[root@xiaoyequ tomcat]# docker build -t diytomcat .
......
Successfully built 28e918d5b143
Successfully tagged diytomcat:latest
# 查看确定构建完毕！
[root@xiaoyequ tomcat]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
diytomcat latest 28e918d5b143 48 seconds ago 686MB
运行启动 run
docker run -d -p 3344:8080 --name mydiytomcat -v /home/tomcat/test:/usr/local/apache-tomcat-9.0.36/webapps/test -v /home/tomcat/tomcat9logs/:/usr/local/apache-tomcat-9.0.36/logs --privileged=true diytomcat注意容器内的路径，文件名
备注：Docker挂载主机目录Docker访问出现cannot open directory .: Permission denied
解决办法：在挂载目录后多加一个--privileged=true参数即可
验证测试访问！ curl localhost:3344
结合前面学习的容器卷将测试的web服务test发布
web.xml：
test
a.jsp：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
hello，xiaoyequ
-----------welcome------------
<%=" my docker tomcat，xiaoyequ"%>
<% System.out.println("-------my docker tomcat-------");%>
测试
查看日志
