Docker Image → A Docker image is an immutable file that contains source code, libraries, dependencies, tools, and other files needed for an application to run(like “my image” from below instructions)
COPY *.properties /app/properties
COPY *.jar /app/jars/
RUN make /app
CMD python /app/app.py
This image is usually built by executing Docker instructions(like above) , which add layers on top of an existing image or os distribution(like ubuntu).
Assume it as ONION with layers(instructions like copy,cmd…