Day2-1. List out all INSTRUCTION statement of docker and give one line explanation.
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FROM – base image to start creating the new image
RUN – Run command in a container created from previous line/layer
ARG – Set a variable for docker file execution and reuse using $(varname)
ENV – Meta layer to set environment for the container
EXPOSE – Sepcify information port for the container and also can be used during port forwarding
COPY – Copy the file in same location as Docker file to container location
ADD – Copy the file in same location as Docker file and extract to destination location in container
USER – default is root user. Can configure which user to run the container
WORKDIR – user work directory
CMD – To set the PID1. This can be replaced while starting the container using “docker run <image name> <process/command>”
ENTRYPOINT – To set the PID1. This can not be replaced while starting. Any parameter passing in docker run will consider parameters for PID1 “docker run <image name> <params>”
VOLUME – The VOLUME command will specify a mount point in the container. This mount point will be mapped to a location on the host that is either specified when the container is created or if not specified chosen automatically from a directory created in /var/lib/docker/volumes