Unable to find user root: no matching entries in passwd file in Docker
You can use this command to access to the container with root user:
docker exec -u 0 -i -t {container_name_or_hash} /bin/bash
try debug with that. i think the script maybe remove or disable root user.
This issue is caused by a docker engine bug but which is tracked privately, Docker is asking users to restart the engine!
It seems that the bug is likely to be older than two years!
https://forums.docker.com/t/unable-to-find-user-root-no-matching-entries-in-passwd-file/26545/7
... what can I say, someone is doing his best to get more funding.
Its a Long standing issue, replicated on my old version 1.10.3 to at least 1.17
As mentioned by @sorin the the docker forum says Running docker stop and then docker start fixes the problem but is hardly a long-term solution...
The docker exec -u 0 -i -t {container_name_or_hash} /bin/bash solution also in the same forum post mentioned here by @ObranZoltan might work for you, but does not work for many. See my output below
$ sudo docker exec -u 0 -it berserk_nobel /bin/bash exec: "/bin/bash": stat /bin/bash: input/output error