How to move a containerized application to a different host?
From what I understand of https://stackoverflow.com/questions/28734086/how-to-move-docker-containers-between-different-hosts, docker export will only save the container filesystem. But no metadata such as the default command, leading to that error when you try to run the imported archive:

sh# IMAGE=$(docker import phpbb.tar)                                                                                                                                       
sh# docker run "${IMAGE}"
docker: Error response from daemon: No command specified.



Given my need, it is sufficient to docker commit the container to a new image, then docker save the image, and finally docker load and docker run it on the new host:

old# docker commit CONTAINER name:tag
old# docker save name:tag |gzip &gt; archive.tar.gz
old# scp archive.tar.gz root@new:.




new# docker load &lt; archive.tar.gz
new# docker run name:latest


It is important to save the image by repository name:tag and not by id to preserve the tag in the archive.