Right now, using Docker on YARN has some hard requirements. If these requirements are not met, then launching the containers will fail and and error message will be printed. Depending on how familiar the user is with Docker, it might or might not be easy for them to understand what went wrong and how to fix the underlying problem.
It would be important to explicitly document these requirements along with the error messages.
#1: CGroups handler cannot be systemd
If docker deamon runs with systemd cgroups handler, we receive the following error upon launching a container:
Solution: switch to cgroupfs. Doing so can be OS-specific, but we can document a systemcl example.
#2: /bin/bash must be present on the $PATH inside the container
Some smaller images like "busybox" or "alpine" does not have /bin/bash. It's because all commands under /bin are linked to /bin/busybox and there's only /bin/sh.
If we try to use these kind of images, we'll see the following error message:
#3: find command must be available on the $PATH
It seems obvious that we have the find command, but even very popular images like fedora requires that we install it separately.
If we don't have find available, then launcher_container.sh fails with:
#4 Add cmd-line example of how to tag local images
This is actually documented under "Privileged Container Security Consideration", but an one-liner would be helpful. I had trouble running a local docker image and tagging it appropriately. Just an example like docker tag local_ubuntu local/ubuntu:latest is already very informative.