A while ago I created a vm running postfix and s-nail to pipe mails to a bash script. The script then verifies the sender and recipient, scans for some keywords and does a http GET request. It is a restricted service running only on our local network.
Now I would like to forge this into a docker image. As I am new to creating Docker Images, I need some help.
How can I pack postfix, s-nail and the script into a Docker image? Do the services need to be separated or can it be one single container?
There are many different ways to do that.
You can put it all together in a one single docker-image. You can use ubuntu as a base image and install your software on it. It's works and is simple. Perhaps it is a good starting-point to learn docker.
FROM ubuntu
# install deps with normal apt
RUN apt update && apt install postfix s-nail
# and you need an entrypoint, which will start both services
But generally, we try to put only one service in a container. If you want to split up, you need a way orchestrate them (spinning containers up, ensure that containers can talk to each other).
If you want to split up, then I recommend docker-compose. It's very easy.
If you want a more advanced setup, then you can use kubernetes.