{"id":825,"date":"2023-08-13T22:19:25","date_gmt":"2023-08-13T16:49:25","guid":{"rendered":"https:\/\/www.openwriteup.com\/?page_id=825"},"modified":"2024-04-02T16:41:04","modified_gmt":"2024-04-02T11:11:04","slug":"dockerfile","status":"publish","type":"page","link":"https:\/\/www.openwriteup.com\/?page_id=825","title":{"rendered":"Dockerfile"},"content":{"rendered":"

This labs is about creating image from dockerfile.<\/p>\n

Youtube Link:<\/strong> Navigation for lab<\/a><\/span><\/p>\n

mkdir doclab\r\ncd doclab<\/pre>\n
Create a dockerfile using vi editor<\/strong>\r\nFROM debian:stable\r\nLABEL authors=\"amit\"\r\nRUN apt-get update && apt-get install -y --force-yes apache2\r\nEXPOSE 80<\/pre>\n
- Save the dockerfile\r\n- docker build -t mydeb .<\/pre>\n
\"\"<\/a><\/p>\n
    \n
  1. FROM debian:stable<\/code>: This sets the base image for your Docker image as the official Debian stable image.<\/li>\n
  2. LABEL authors=\"amit\"<\/code>: This adds a label to your image indicating the author as “amit”. Labels are metadata that can be used to provide information about the image.<\/li>\n
  3. RUN apt-get update && apt-get install -y --force-yes apache2<\/code>: This command updates the package list and then installs the Apache2 web server package. The -y<\/code> flag automatically confirms any prompts during the installation process, and --force-yes<\/code> is used to force installation without confirmation, which can be risky and is generally not recommended.<\/li>\n
  4. EXPOSE 80<\/code>: This instruction indicates that the container will listen on port 80. It’s a declaration of the intended network ports that the container will listen on when running.<\/li>\n<\/ol>\n
    docker images\r\ndocker inspect <imageid><\/pre>\n
    \"\"<\/a><\/p>\n
     <\/p>\n
    COPY and ADD example<\/p>\n
    Create a docker file dockerfileadd<\/p>\n
    touch file.txt\r\nvi dockerfileadd and copy below code, save it\r\n\r\nFROM ubuntu:latest\r\n# Set a working director inside container\r\nWORKDIR \/app\r\n#Copy file from current directory\r\nCOPY file.txt \/app\/\r\n#ADD a directory from the host\r\n#ADD \/home\/lab-user\/amit \/app\/\r\nADD https:\/\/github.com\/amitopenwriteup\/my_proj\/blob\/master\/k8s-setup.txt \/app\/\r\n#Till this point copy it in docker file\r\n\r\n#below command run in the shell\r\n\r\ndocker build -t myweb2 -f dockerfileadd .\r\n\r\ndocker images\r\n\r\ndocker run\u00a0 -it <imageid,from image command> \/bin\/bash\r\nexit<\/pre>\n
    RUN,CMD and ENTRYPOINT\u00a0<\/strong><\/p>\n
    Lab1<\/p>\n
    1)mkdir test\r\ncd test\r\nvi date.sh\u00a0\r\n\r\n\/\/Copy the below code in date.sh\r\n\r\n#!\/bin\/sh\r\necho `date` $@ >> log.txt;\r\ncat log.txt;\r\n#save date.sh script<\/pre>\n
     <\/p>\n
    \"\"<\/a><\/p>\n
    chmod 777 date.sh<\/pre>\n
    Create a docker file named mydockerfile and copy the below line<\/p>\n
    FROM alpine\r\nADD date.sh \/\r\nRUN [\"\/date.sh\", \"image created\"]<\/pre>\n
    docker build -t myimage -f mydockerfile .<\/pre>\n
     <\/p>\n
    \"\"<\/a><\/p>\n
    docker run myimage cat log.txt\r\nCheck the time<\/pre>\n
    \"\"<\/a><\/p>\n
    If we run the container several times, we’ll see that the date in our
    \nlog file doesn’t change. This makes sense because the run step
    \nexecutes at image build time, not at the container runtime.<\/p>\n
    Lab2 Create a new docker file named mydockerfile1<\/strong><\/p>\n
    FROM alpine\r\nADD date.sh \/\r\nRUN [\"\/date.sh\", \"image created\"]\r\nCMD [\"\/date.sh\", \"container started\"]<\/pre>\n
    docker build -t myimage1 -f mydockerfile1 .\r\n\r\ndocker run myimage1<\/pre>\n
    \"\"<\/a><\/p>\n
    If we run this multiple times, we’ll see that the image created entry
    \nstays the same. But the container started entry updates with every
    \nrun. This shows how cmd indeed executes every time the container
    \nstarts.<\/p>\n
    Lab3: create a new dockerfile mydockerfile2 Lets add two cmd commands.<\/strong><\/p>\n
    FROM alpine\r\nADD date.sh \/\r\nRUN [\"\/date.sh\", \"image created\"]\r\nCMD [\"\/date.sh\", \"container started\"]\r\nCMD [\"\/date.sh\", \"container running\"]<\/pre>\n
    docker build -t myimage2 -f mydockerfile2 .\r\n\r\ndocker run myimage2<\/pre>\n
    \"\"<\/a><\/p>\n
    Lab4 : ENTRYPOINT<\/strong><\/p>\n
    Create a dockerfile name mydockerfile3<\/p>\n
    FROM alpine\r\nADD date.sh \/\r\nRUN [\"\/date.sh\", \"image created\"]\r\nENTRYPOINT [\"\/date.sh\"]<\/pre>\n
    docker build -t myimage3 -f mydockerfile3 .\r\n\r\ndocker run myimage3 welcome to container<\/pre>\n
    \"\"<\/a><\/p>\n
     <\/p>\n","protected":false},"excerpt":{"rendered":"
    This labs is about creating image from dockerfile. Youtube Link: Navigation for lab mkdir doclab cd doclab Create a dockerfile using vi editor FROM debian:stable LABEL authors=”amit” RUN apt-get update && apt-get install -y –force-yes apache2 EXPOSE 80 – Save the dockerfile – docker build -t mydeb . FROM debian:stable: This sets the base image […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_oct_exclude_from_cache":false,"footnotes":""},"class_list":["post-825","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.openwriteup.com\/index.php?rest_route=\/wp\/v2\/pages\/825","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.openwriteup.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.openwriteup.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.openwriteup.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.openwriteup.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=825"}],"version-history":[{"count":10,"href":"https:\/\/www.openwriteup.com\/index.php?rest_route=\/wp\/v2\/pages\/825\/revisions"}],"predecessor-version":[{"id":1412,"href":"https:\/\/www.openwriteup.com\/index.php?rest_route=\/wp\/v2\/pages\/825\/revisions\/1412"}],"wp:attachment":[{"href":"https:\/\/www.openwriteup.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=825"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}