Docker.IO Filesystem Consistancy

Question

I created a docker container, and then I created a file and exited the container.

When I restart the container with:

docker run -i -t ubuntu /bin/bash

the file is nowhere to be found. I checked /var/lib/docker/ and there is another folder created which has my file in it. I know it's something to do with Union FS.

1. How do I start the same container again with my file in it?
2. How do I export a container with file change?

Answer 1

I don't know if this will answer your question completely, but...

Doing docker run -i -t ubuntu /bin/bash will not restart any container. Instead, it will create and start a new container based on the ubuntu image.

If you started a container and stopped it you can use docker start ${CONTAINER_ID}. If you did not stop it yet you can use restart.

You can also commit (export) the container to a new image: see http://docs.docker.io/en/latest/commandline/command/commit/ for the correct syntax. docker export is a option as well, but all that will do is archive your container. By creating a new image using docker commit you can create multiple instances (containers) of it afterwards, all having your file in it.