如何使用Dockerfile构建一个tomcat镜像？针对这个问题，这篇文章详细介绍了相对应的分析和解答，希望可以帮助更多想解决这个问题的小伙伴找到更简单易行的方法。
dockerfile 是用来构建docker镜像的文件！命令参数脚本！
构建步骤：
# 以contes为例 查看 dockerhub 上 contes 的 dockerfile 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="20200809" \ org.opencontainers.image.title="CentOS Base Image" \ org.opencontainers.image.vendor="CentOS" \ org.opencontainers.image.licenses="GPL-2.0-only" \ org.opencontainers.image.created="2020-08-09 00:00:00+01:00" CMD ["/bin/bash"]
DockerFile构建过程
基础知识：
dockerfile是面向开发的，我们以后要发布项目，做镜像，就需要编写dockerfile文件，这个文件十分简单！
Docker镜像逐渐成为企业交付的标准！
DockerFile：构建镜像，定义了一切的步骤，源代码；
DockerImages：通过DockerFile构建生成的一个镜像，这个镜像就是我们最终发布和运行的产品！
Docker容器：容器就是镜像运行起来提供服务！
DockerFile的指令
FROM # 基础镜像 MAINTAINER # 镜像是谁写的 姓名 + 邮箱 RUN # 镜像构建的时候需要运行的命令 ADD # 步骤 eg:tomcat镜像---》放入tomcat的压缩包！添加内容 WORKDIR # 镜像的工作目录 VOLUME # 挂载的目录位置 EXPOST # 暴露端口配置 CMD # 指定这个容器启动的时候要运行的命令,只有最后一个会生效，可被替代 ENTRYPOINT # 指定这个容器启动的时候要运行的命令，可以追加命令 ONBUILD # 当构建一个被继承的 DockerFile ，这个时候就会运行 ONBUILD 的指令，触发指令 COPY # 类似ADD，将我们的文件拷贝到镜像中 ENV # 构建的时候设置环境变量
实战测试
Docker Hub 中 99% 的镜像都是从 FROM scratch 这个基础镜像过来的 ，然后配置我们需要的软件和配置来进行构建
创建一个自己的centos
# 1、编写DockerFile的文件
FROM centos
# 作者信息
MAINTAINER yinxiaodong<m15010969094@163.com>
# 配置环境变量
ENV MYPATH /user/local
# 指定镜像的工作目录
WORKDIR $MYPATH
RUN yum install -y vim
RUN yum install -y net-tools
# 暴露80端口
EXPOSE 80
CMD echo $MYPATH
CMD echo "---------end--------"
CMD /bin/bash
# 2、通过文件构建镜像
# 命令 docker build -f dockerfile文件路径 -t 镜像名:版本号 .
[root@localhost dockerfile]# docker build -f mydockerfile-centos -t mycentos:0.1 .
Sending build context to Docker daemon 2.048kB
Step 1/9 : FROM centos
---> 0d120b6ccaa8
Step 2/9 : MAINTAINER yinxiaodong<m15010969094@163.com>
---> Running in f79b12ffb083
Removing intermediate container f79b12ffb083
---> 8ee53d3f7a65
Step 3/9 : ENV MYPATH /user/local
---> Running in 659a2c96d5f7
Removing intermediate container 659a2c96d5f7
---> 59ab131ef44c
Step 4/9 : WORKDIR $MYPATH
---> Running in 0b4b8f9c65bb
Removing intermediate container 0b4b8f9c65bb
---> 408b06671488
Step 5/9 : RUN yum install -y net-tools
---> Running in 151f81148a87
CentOS-8 - AppStream 118 kB/s | 5.8 MB 00:50
CentOS-8 - Base 218 kB/s | 2.2 MB 00:10
CentOS-8 - Extras 1.8 kB/s | 7.3 kB 00:04
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 219 kB/s | 323 kB 00:01
--------------------------------------------------------------------------------
Total 66 kB/s | 323 kB 00:04
warning: /var/cache/dnf/BaseOS-f6a80ba95cf937f2/packages/net-tools-2.0-0.51.20160912git.el8.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID 8483c65d: NOKEY
CentOS-8 - Base 162 kB/s | 1.6 kB 00:00
Importing GPG key 0x8483C65D:
Userid : "CentOS (CentOS Official Signing Key) <security@centos.org>"
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 : 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 151f81148a87
---> c0a0546c9b2a
Step 6/9 : EXPOSE 80
---> Running in 42000936515d
Removing intermediate container 42000936515d
---> fe68114ecf3f
Step 7/9 : CMD echo $MYPATH
---> Running in c393fc53a354
Removing intermediate container c393fc53a354
---> a6924276bf90
Step 8/9 : CMD echo "---------end--------"
---> Running in 5994de56f0a1
Removing intermediate container 5994de56f0a1
---> a8ba0ebb3770
Step 9/9 : CMD /bin/bash
---> Running in d1fa2d436363
Removing intermediate container d1fa2d436363
---> 41bb76be4884
Successfully built 41bb76be4884
Successfully tagged mycentos:0.1
[root@localhost dockerfile]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
mycentos 0.1 41bb76be4884 7 seconds ago 246MB
centos 1.0 d840628c30a9 6 hours ago 215MB
centos latest 0d120b6ccaa8 2 days ago 215MB
# 启动 mycentos 使用 ifconfig 命令查看ip信息
[root@localhost dockerfile]# docker run -it mycentos:0.1
[root@494c2bc72263 local]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.17.0.3 netmask 255.255.0.0 broadcast 172.17.255.255
ether 02:42:ac:11:00:03 txqueuelen 0 (Ethernet)
RX packets 6 bytes 516 (516.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 1000 (Local Loopback)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
# 查看所在目录 /user/local 正是我们在dockerfile中指定的目录
[root@494c2bc72263 local]# pwd
/user/local查看镜像的构建历史记录
# 命令 docker history 镜像id [root@localhost ~]# docker history 41bb76be4884 IMAGE CREATED CREATED BY SIZE COMMENT 41bb76be4884 16 minutes ago /bin/sh -c #(nop) CMD ["/bin/sh" "-c" "/bin… 0B a8ba0ebb3770 16 minutes ago /bin/sh -c #(nop) CMD ["/bin/sh" "-c" "echo… 0B a6924276bf90 16 minutes ago /bin/sh -c #(nop) CMD ["/bin/sh" "-c" "echo… 0B fe68114ecf3f 16 minutes ago /bin/sh -c #(nop) EXPOSE 80 0B c0a0546c9b2a 16 minutes ago /bin/sh -c yum install -y net-tools 31.3MB 408b06671488 17 minutes ago /bin/sh -c #(nop) WORKDIR /user/local 0B 59ab131ef44c 17 minutes ago /bin/sh -c #(nop) ENV MYPATH=/user/local 0B 8ee53d3f7a65 17 minutes ago /bin/sh -c #(nop) MAINTAINER yinxiaodong<m1… 0B 0d120b6ccaa8 2 days ago /bin/sh -c #(nop) CMD ["/bin/bash"] 0B <missing> 2 days ago /bin/sh -c #(nop) LABEL org.label-schema.sc… 0B <missing> 2 days ago /bin/sh -c #(nop) ADD file:538afc0c5c964ce0d… 215MB
我们平时拿到一个镜像，可以研究一下它是怎么做的---->docker history 镜像id
CMD 和 ENTRYPOINT 的区别
CMD # 指定这个容器启动的时候要运行的命令,只有最后一个会生效，可被替代 ENTRYPOINT # 指定这个容器启动的时候要运行的命令，可以追加命令 # 测试 CMD # 编写DockerFile的文件 [root@localhost dockerfile]# cat dockerfile-cmd-test FROM centos CMD ["ls","-a"] # 根据 DockerFile 构建镜像 [root@localhost dockerfile]# docker build -f dockerfile-cmd-test -t testcmd:0.1 . Sending build context to Docker daemon 3.072kB Step 1/2 : FROM centos ---> 0d120b6ccaa8 Step 2/2 : CMD ["ls","-a"] ---> Running in b3f8ba72222b Removing intermediate container b3f8ba72222b ---> 561e47f88730 Successfully built 561e47f88730 Successfully tagged testcmd:0.1 # 构建成功 # 查看镜像 [root@localhost dockerfile]# docker images REPOSITORY TAG IMAGE ID CREATED SIZE testcmd 0.1 561e47f88730 6 seconds ago 215MB centos latest 0d120b6ccaa8 2 days ago 215MB # 启动镜像 发现ls -a命令生效 [root@localhost dockerfile]# docker run -it testcmd:0.1 . .dockerenv dev home lib64 media opt root sbin sys usr .. bin etc lib lost+found mnt proc run srv tmp var # 启动命令中 追加一个 -l, 我们期望的是 ls -a -l,但是 报错，这里将 ls -a 替换成了 -l，最终的命令是 -l 所以报错。 [root@localhost dockerfile]# docker run -it 561e47f88730 -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. # 将启动命令替换成 docker run -it testcmd:0.1 ls -al， 成功打印详细信息; [root@localhost dockerfile]# docker run -it testcmd:0.1 ls -al total 0 drwxr-xr-x. 1 root root 6 Aug 13 08:20 . drwxr-xr-x. 1 root root 6 Aug 13 08:20 .. -rwxr-xr-x. 1 root root 0 Aug 13 08:20 .dockerenv lrwxrwxrwx. 1 root root 7 May 11 2019 bin -> usr/bin drwxr-xr-x. 5 root root 360 Aug 13 08:20 dev drwxr-xr-x. 1 root root 66 Aug 13 08:20 etc drwxr-xr-x. 2 root root 6 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 6 Aug 9 21:40 lost+found drwxr-xr-x. 2 root root 6 May 11 2019 media drwxr-xr-x. 2 root root 6 May 11 2019 mnt drwxr-xr-x. 2 root root 6 May 11 2019 opt dr-xr-xr-x. 123 root root 0 Aug 13 08:20 proc dr-xr-x---. 2 root root 162 Aug 9 21:40 root drwxr-xr-x. 11 root root 163 Aug 9 21:40 run lrwxrwxrwx. 1 root root 8 May 11 2019 sbin -> usr/sbin drwxr-xr-x. 2 root root 6 May 11 2019 srv dr-xr-xr-x. 13 root root 0 Aug 11 09:58 sys drwxrwxrwt. 7 root root 145 Aug 9 21:40 tmp drwxr-xr-x. 12 root root 144 Aug 9 21:40 usr drwxr-xr-x. 20 root root 262 Aug 9 21:40 var # 测试二：现在我们把 DockerFile 中 CMD 替换成 ENTRYPOINT 后重新构建，运行 看看结果 [root@localhost dockerfile]# cat dockerfile-cmd-test FROM centos ENTRYPOINT ["ls","-a"] # 重新构建镜像 [root@localhost dockerfile]# docker build -f dockerfile-cmd-test -t testcmd:0.2 . Sending build context to Docker daemon 3.072kB Step 1/2 : FROM centos ---> 0d120b6ccaa8 Step 2/2 : ENTRYPOINT ["ls","-a"] ---> Running in c634ca09fabe Removing intermediate container c634ca09fabe ---> 52d295395f08 Successfully built 52d295395f08 Successfully tagged testcmd:0.2 # 查看镜像 [root@localhost dockerfile]# docker images REPOSITORY TAG IMAGE ID CREATED SIZE testcmd 0.2 52d295395f08 7 seconds ago 215MB testcmd 0.1 561e47f88730 12 minutes ago 215MB centos latest 0d120b6ccaa8 2 days ago 215MB # 运行testcmd：0.2镜像 并追加 -l ,发现 打印出了详细信息 [root@localhost dockerfile]# docker run -it testcmd:0.2 -l total 0 drwxr-xr-x. 1 root root 6 Aug 13 08:17 . drwxr-xr-x. 1 root root 6 Aug 13 08:17 .. -rwxr-xr-x. 1 root root 0 Aug 13 08:17 .dockerenv lrwxrwxrwx. 1 root root 7 May 11 2019 bin -> usr/bin drwxr-xr-x. 5 root root 360 Aug 13 08:17 dev drwxr-xr-x. 1 root root 66 Aug 13 08:17 etc drwxr-xr-x. 2 root root 6 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 6 Aug 9 21:40 lost+found drwxr-xr-x. 2 root root 6 May 11 2019 media drwxr-xr-x. 2 root root 6 May 11 2019 mnt drwxr-xr-x. 2 root root 6 May 11 2019 opt dr-xr-xr-x. 121 root root 0 Aug 13 08:17 proc dr-xr-x---. 2 root root 162 Aug 9 21:40 root drwxr-xr-x. 11 root root 163 Aug 9 21:40 run lrwxrwxrwx. 1 root root 8 May 11 2019 sbin -> usr/sbin drwxr-xr-x. 2 root root 6 May 11 2019 srv dr-xr-xr-x. 13 root root 0 Aug 11 09:58 sys drwxrwxrwt. 7 root root 145 Aug 9 21:40 tmp drwxr-xr-x. 12 root root 144 Aug 9 21:40 usr drwxr-xr-x. 20 root root 262 Aug 9 21:40 var
DockerFile中很多命令都十分相似，我们需要了解他的区别，最好的学习就是对比进行测试查看效果！
实战:Tomcat镜像
1、准备镜像文件 tomcat压缩包 jdk压缩包
[root@localhost tomcat]# ls
apache-tomcat-8.5.43.tar.gz Dockerfile jdk-8u211-linux-x64.tar.gz read.txt
2、编写dockerfile文件, 官方命名Dockerfile，build会自动寻找这个文件，不需要 -f 指定！
# 引入基础 FROM centos # 作者信息 MAINTAINER yinxiaodoong<m15010969094@163.com> # copy文件read.txt到容器的 /usr/local/read.txt 目录下 COPY read.txt /usr/local/read.txt # 添加jdk tomcat ---> 自动解压 ADD jdk-8u211-linux-x64.tar.gz /usr/local/ ADD apache-tomcat-8.5.43.tar.gz /usr/local/ # 安装 vim 命令 RUN yum install -y vim # 配置 MYPATH ENV MYPATH /usr/local/ # 指定 进入容器默认路径 /user/local/ WORKDIR $MYPATH # 配置jdk环境变量 ENV JAVA_HOME /usr/local/jdk1.8.0_211 ENV CLASSPATH $JAVA_HOME/lib/dt.jat:$JAVA_HOME/lib/tools.jar # 配置tomcat环境变量 ENV CATALINA_HOME /usr/local/apache-tomcat-8.5.43 ENV CATALINA_BASH /usr/local/apache-tomcat-8.5.43 ENV PATH $PATH:$JAVA_HOME/bin:$CATALINA_HOME/lib:$CATALINA_HOME/bin # 暴露8080端口 EXPOSE 8080 # /usr/local/tomcat/webapps# # 启动容器时 启动tomcat CMD /usr/local/apache-tomcat-8.5.43/bin/startup.sh && tail -f /usr/local/apache-tomcat-8.5.43/logs/catalina.out # 构建tomcat镜像 [root@localhost tomcat]# docker build -t mytomcat [root@localhost tomcat]# docker images REPOSITORY TAG IMAGE ID CREATED SIZE mytomcat latest a9707559afa1 8 seconds ago 693MB centos latest 0d120b6ccaa8 4 days ago 215MB [root@localhost tomcat]# docker run -d -p 8081:8080 --name mytomcat--01 -v /home/yinxiaodong/build/tomcat/test:/usr/local/apache-tomcat-8.5.43/webapps/test -v /home/yinxiaodong/build/tomcat/logs:/usr/local/apache-tomcat-8.5.43/logs mytomcat
发布自己的镜像
发布到 dockerHub
地址 https://hub.docker.com/ 注册自己的账号
确定自己的账号可以登录
在我们的服务器上提交
[root@localhost logs]# docker login --help Usage: docker login [OPTIONS] [SERVER] Log in to a Docker registry. If no server is specified, the default is defined by the daemon. Options: -p, --password string Password --password-stdin Take the password from stdin -u, --username string Username [root@localhost logs]# [root@localhost logs]# docker login -u xxx -p xxx WARNING! Using --password via the CLI is insecure. Use --password-stdin. WARNING! Your password will be stored unencrypted in /root/.docker/config.json. Configure a credential helper to remove this warning. See https://docs.docker.com/engine/reference/commandline/login/#credentials-store Login Succeeded
登录完毕后就可以提交镜像了
[root@localhost logs]# docker push xxx/mytomcat:1.0
关于如何使用Dockerfile构建一个tomcat镜像问题的解答就分享到这里了，希望以上内容可以对大家有一定的帮助，如果你还有很多疑惑没有解开，可以关注亿速云行业资讯频道了解更多相关知识。
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