How can container user and host user both have access to same files in volume?

Question

I'm using Docker namespaces in an effort to allow files created within a volume to be arbitrarily read and written to by both the container user and the host user (please let me know if this is even a valid approach to what I'm trying to do!).

My host username is aryzing. So I'm running the docker deamon as

dockerd --userns-remap=aryzing

The volume maps my host's ~/workspace/app to the volume's /usr/src/app.

From the host system I have no issue modifying the files, but from within the container, I have access errors. Specifically, I'm running NPM's install command from within the container, npm install, and it's unable to install the packages due to a permissions error:

Error: EACCES: permission denied, access '/usr/src/app/node_modules'

As per this post I've also tried running the container with the --user flag, and ran into the same issue.

Any suggestions on how to achive the functionality I'm after?

Answer 1

I was tripping myself up: when I was trying the --user flag, I still had --userns-remap set. Running the daemon without --userns-remap did the trick.