Dockerfile:
Docker can build images automatically by reading the instructions from a Dockerfile. A Dockerfile is a text file that contains instructions for building a Docker image. It tells Docker what base image to use, what commands to run, and what files to include. For example, if you were making a container for a website, the Dockerfile might tell Docker to use an official web server image, copy the files for your website into the container, and start the web server when the container starts.
Dockerfile instructions:
FROM Create a new build stage from a base image.
RUN Execute build commands.
WORKDIR Change working directory.
VOLUME Create volume mounts.
COPY Copy files and directories.
ADD Add local or remote files and directories.
ARG Use build-time variables.
ENTRYPOINT Specify default executable.
CMD Specify default commands.
ENV Set environment variables.
EXPOSE Describe which ports your application is listening on.
HEALTHCHECK Check a container's health on startup.
LABEL Add metadata to an image.
MAINTAINER Specify the author of an image.
ONBUILD Specify instructions for when the image is used in a build.
SHELL Set the default shell of an image.
STOPSIGNAL Specify the system call signal for exiting a container.
USER Set user and group ID.
Let's learn how to write a Dockerfile and build image.
Dockerfile to to create a python app.
Build docker image -- docker build -t python-app .
Run container from above image -- docker run -d -p 5000:5000 --name python-app python-app
Check if the app is running fine -- public_ip/5000
Now push image to Docker Hub(Public repository)
Docker login on docker host
Now, we need to tag the image we want push to docker hub
Now, push the image to docker hub and verify in docker hub
