Docker 之 Dockerfile 的概述與使用

一、dockerfile 概述

二、USER\WORKDIR 命令

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創(chuàng)建一個(gè)dockerfile文件

[root@docker dockerfile]# vi Dockerfile       #必須文件為Dockerfile
FROM nginx:latest        #使用那個(gè)鏡像作為底包   
USER nginx                   #指定那個(gè)用戶運(yùn)行
WORKDIR /usr/share/nginx/html          #指定運(yùn)行的時(shí)的目錄位置

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生成一個(gè)鏡像
[root@docker dockerfile]# docker build . -t myselfnginx:latest
Sending build context to Docker daemon  2.048kB
Step 1/3 : FROM nginx:latest
 ---> f7bb5701a33c
Step 2/3 : USER nginx
 ---> Running in 846447177e73
Removing intermediate container 846447177e73
 ---> 98d5ad96fdfa
Step 3/3 : WORKDIR /usr/share/nginx/html
 ---> Running in e500aea99e2c
Removing intermediate container e500aea99e2c
 ---> a6e377307258
Successfully built a6e377307258
Successfully tagged myselfnginx:latest
[root@docker dockerfile]# docker images
REPOSITORY            TAG                     IMAGE ID            CREATED             SIZE
myselfnginx           latest                  a6e377307258        26 seconds ago      126MB
zhoumingkang/nginx    curl                    d1b81c37853c        25 hours ago        152MB
myalpine              latest_with_hello.txt   3ce9b8b899ba        2 days ago          5.59MB
nginx                 latest                  f7bb5701a33c        11 days ago         126MB
zhoumingkang/alpine   v3.10.3                 cc0abc535e36        2 weeks ago         5.59MB
alpine                latest                  cc0abc535e36        2 weeks ago         5.59MB
alpine                3.9.4                   055936d39205        8 months ago        5.53MB
hello-world           latest                  fce289e99eb9        12 months ago       1.84kB
[root@docker dockerfile]# docker run -ti --rm myselfnginx:latest /bin/bash
nginx@51ddb8d7c3e3:/usr/share/nginx/html$ whoami
nginx
nginx@51ddb8d7c3e3:/usr/share/nginx/html$ pwd
/usr/share/nginx/html
nginx@51ddb8d7c3e3:/usr/share/nginx/html$ 

三、ADD\EXPOSE 命令

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創(chuàng)建一個(gè)dockerfile文件
[root@docker dockerfile]# cat Dockerfile 
FROM nginx:latest
ADD index.html /usr/share/nginx/html
EXPOSE 80

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生成一個(gè)鏡像
docker build . -t nginx:with_add_expose
Sending build context to Docker daemon   5.12kB
Step 1/3 : FROM nginx:latest
 ---> f7bb5701a33c
Step 2/3 : ADD index.html /usr/share/nginx/html
 ---> 7e2b905eca85
Step 3/3 : EXPOSE 80
 ---> Running in f13c2538a707
Removing intermediate container f13c2538a707
 ---> d44bd64abd82
Successfully built d44bd64abd82
Successfully tagged nginx:with_add_expose
[root@docker dockerfile]# docker build . -t centos7:with_install_bind

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通過該鏡像運(yùn)行容器
[root@docker dockerfile]# docker run --rm -d -P nginx:with_add_expose    
#大寫P為宿主機(jī)隨機(jī)生成一個(gè)端口指向內(nèi)部80端口
f19df2f5124538faf3660079e9d6bd5dbb10d54a75f3233847164caa0ef7c44c
[root@docker dockerfile]# docker ps
CONTAINER ID        IMAGE                   COMMAND                  CREATED             STATUS              PORTS                   NAMES
f19df2f51245        nginx:with_add_expose   "nginx -g 'daemon of…"   5 seconds ago       Up 4 seconds        0.0.0.0:32770->80/tcp   nervous_colden

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登陸容器查看index.html文件是否存在
[root@docker dockerfile]# docker exec -ti nervous_colden /bin/bash
root@f19df2f51245:/# cd /usr/share/nginx/html/
root@f19df2f51245:/usr/share/nginx/html# ls
50x.html  index.html

四、RUN\ENV 命令

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創(chuàng)建Dockerfile文件
[root@docker dockerfile]# cat Dockerfile 
FROM centos:centos7
ENV VER 9.11.4
RUN yum -y install bind-$VER        
#RUN 命令是在我們構(gòu)建鏡像時(shí)運(yùn)行的命令，并不是指在容器里運(yùn)行命令

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通過該鏡像運(yùn)行容器，并查環(huán)境變量與安裝包是否已經(jīng)成功
[root@docker dockerfile]# docker run -ti centos7:with_install_bind /bin/bash
[root@647dbdb37662 /]# env
HOSTNAME=647dbdb37662
TERM=xterm
LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=01;05;37;41:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.jpg=01;35:*.jpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.axv=01;35:*.anx=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=01;36:*.au=01;36:*.flac=01;36:*.mid=01;36:*.midi=01;36:*.mka=01;36:*.mp3=01;36:*.mpc=01;36:*.ogg=01;36:*.ra=01;36:*.wav=01;36:*.axa=01;36:*.oga=01;36:*.spx=01;36:*.xspf=01;36:
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
PWD=/
SHLVL=1
HOME=/root
VER=9.11.4
_=/usr/bin/env
[root@647dbdb37662 /]# rpm -qa bind
bind-9.11.4-9.P2.el7.x86_64
[root@647dbdb37662 /]# 

五、CMD 命令

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創(chuàng)建Dockerfile文件
[root@docker dockerfile]# cat Dockerfile 
FROM centos:centos7
RUN yum -y install httpd
CMD ["httpd","-D","FOREGROUND"]

#關(guān)于RUN與CMD的區(qū)別
#RUN是創(chuàng)建鏡像是運(yùn)行的命令
#CMD是啟動(dòng)容器后，幫你運(yùn)行的命令

[root@docker dockerfile]# docker build . -t centos7:httpd     
#通過Dockerfile文件創(chuàng)建鏡像

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通過該容器運(yùn)行鏡像
[root@docker dockerfile]# docker run -d --rm -p80:80 --name myhttpd centos7:httpd
2f2c3328befbbd6fffe14d2887c7d3c334e50218de027881659aa30276a0e8bf
[root@docker dockerfile]# docker ps
CONTAINER ID        IMAGE                       COMMAND                 CREATED             STATUS              PORTS                NAMES
2f2c3328befb        centos7:httpd               "httpd -D FOREGROUND"   5 seconds ago       Up 3 seconds        0.0.0.0:80->80/tcp   myhttpd

六、ENTRYPOINT 命令

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創(chuàng)建Dockerfile文件
[root@docker dockerfile]# cat Dockerfile 
FROM centos:centos7
ADD entrypoint.sh /entrypoint.sh       #上傳當(dāng)前目錄上的entrypoint.sh文件，要有執(zhí)行權(quán)限
RUN yum -y install epel-release -q  && yum -y install nginx   #鏡像構(gòu)建時(shí)執(zhí)行命令
ENTRYPOINT /entrypoint.sh           
#定義ENTRYPOINT，并開機(jī)運(yùn)行

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定義entrypoint.sh文件
[root@docker dockerfile]# cat entrypoint.sh 
#!/bin/bash
/sbin/nginx -g "daemon off;"

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構(gòu)建鏡像 
[root@docker dockerfile]# docker build . -t centos7:mynginx

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運(yùn)行容器查看效果
[root@docker dockerfile]# docker run -d -p80:80 --name mynginx centos7:mynginx
b8c8899bf0eb1012c925746f8d544159bbca4b99013f0aea7a7a625483d11868
[root@docker dockerfile]# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                NAMES
b8c8899bf0eb        centos7:mynginx     "/bin/sh -c /entrypo…"   4 seconds ago       Up 3 seconds        0.0.0.0:80->80/tcp   mynginx