This document discusses Dockerfile commands used to build Docker images. It explains key commands like FROM, RUN, ADD, COPY, EXPOSE, VOLUME, CMD and ENTRYPOINT. Examples are provided for each command. The differences between CMD and ENTRYPOINT are explained. Best practices for the Dockerfile and Docker workflow are also briefly covered.

1. Docker Session III
Dockerfile

2. Discussion on
● Dockerfile
● Dockerfile commands
● Dockerfile demo

3. Dockerfile
● What is dockerfile?

4. Docker Workflow

5. Dockerfile commands
● FROM
● RUN
● ADD
● COPY
● EXPOSE
● VOLUMN
● CMD
● ENTRYPOINT

6. FROM <base_image>
● FROM scratch
● FROM ruby:2.5.0
● FROM node:6.0

7. MAINTAINER <name>
● MAINTAINER Degenda SIvakoti <degendra@bajratechnologies.com>
● Deprecated

8. RUN <command>
● RUN apt-get install nodejs
● RUN apt-get update && apt-get install nodejs postgresql nano curl

9. ADD <src> <dest>
● ADD . .
● ADD . /app/
● ADD Gemfile /app/Gemfile

10. COPY <src> <dest>
● COPY . /client
● COPY package.json /client/package.json

11. ADD vs COPY
● ADD has 2 extra capabilities (either or)
○ <src> can be url
○ Archive files will be automatically extracted.
● Add https://google.com/images/a.png /app/images/a.png
● Add file.tar.gz /app

12. GUESS
● Add https://google.com/images/a.png /app/images/b.png
● Add https://google.com/images/a.png /app/images/
● Add https://google.com/images/a.tar.gz /app/
● Add https://google.com/images/a.tar.gz /app/b.tar.gz

13. ANSWER
● Add https://google.com/images/a.png /app/images/b.png
/app/images/b.png
● Add https://google.com/images/a.png /app/images/
/app/images/a.png
● Add https://google.com/images/a.tar.gz /app/
/app/a.tar.gz
● Add https://google.com/images/a.tar.gz /app/b.tar.gz
/app/b.tar.gz

14. EXPOSE <port>
● EXPOSE 80

15. ENV <key> <value>
● ENV RAILS_ENV development
● ENV GO_ENV production

16. ENV <key>=<value>
● ENV RAILS_ENV=development GO_ENV=production
Difference between <key> <value> and <key>=<value>?

17. VOLUME [“/data”]
● VOLUME /var/log
● VOLUME /var/log /var/db
● VOLUME [“/var/log”, “/var/db”]

18. WORKDIR <path>
● Mkdir /demo-app
● WORKDIR /demo-app
● PWD
○ /demo-app

19. SHELL & EXEC
● Shell form
○ RUN <command>
○ RUN echo “Hello World!”
○ /bin/sh -c “echo ‘Hello World!’”
● Exec form
○ RUN [“executable”, “param1”, “param2”]
○ RUN [“/bin/bash”, “-c”, “echo Hello World!”]

20. CMD
● CMD [“executable”, “param1”, “param2”]
● CMD [“param1”, “param2”]
● CMD command param1 param2
● CMD [“/usr/bin/tail”, “-f”, “/dev/null”]

21. ENTRYPOINT
● ENTRYPOINT command param1 param2
● ENTRYPOINT echo “Hello World!”
● CMD [“Hello World!”]
● ENTRYPOINT echo
● ENTRYPOINT echo
● Docker run <image_name> “Hello World”

22. ENTRYPOINT Cont...
● ENTRYPOINT command param1 param2
● ENTRYPOINT echo “Hello World!”
● CMD [“Hello World!”]
● ENTRYPOINT echo //Hello World!
● ENTRYPOINT echo
● Docker run <image_name> “Hello World” //Hello World!

23. OTHERS
● LABEL
● USER
● ONBUILD

24. .dockerignore File
● Similar to .gitignore
● Useful when using ADD and COPY command
○ # comment
○ log/*
○ node_modules/*

25. Docker Workflow Detailed

26. Build Context
● Docker build .
● Docker build -f <dockerfile_name> <build_context>
● Docker run -d -p 8080:80 -v host/path:container/path <image_name>
<commands>

27. Dockerfile Demo
● Finally!!!

28. UPCOMING
● Docker compose
● Docker swarm

29. Queries???

30. Thank You!!!