su terminal get around---docker root

su : must be run from a terminal

After some googling, I found the solution from Tero's glob. If you have python installed, just run the following from your shell:

echo "import pty; pty.spawn('/bin/bash')" > /tmp/asdf.py

python /tmp/asdf.py

30 

You can log into the Docker Image using the root user (ID = 0) instead of the provided default user when you use the -u option. E.g. docker exec -u 0 -it mycontainer bash