Volume bind mounting from docker in docker?

Question

I have a Docker container \"A\" that will start another container \"B\" (by volume mounting /var/run/docker.sock). Now, these containers need to share files.

Container \

Answer 1

If you do not rely on volumes, another way to share files would be to pipe them from "A" to "B". You would need container B to handle input on STDIN, ex. with a custom entrypoint.

In container A:

cat some_file_on_A.txt | docker run -i container_B

Example entrypoint in container B:

while read input_from_A; do
  echo "${input_from_A}" > some_file_on_B.txt
done