What happens if you run a container with user namespace remapping enabled and try to access a file owned by root on the host?

medium📝 Command Output Q5 of 15

Docker - Security

AThe container user is mapped to root on the host, so full access is granted

BThe container user remains root and can access all root-owned files on the host

CThe container cannot start due to permission errors

DThe container user is mapped to a non-root user, so root-owned files appear as owned by an unprivileged user

Step-by-Step Solution

Solution:

Step 1: Understand user ID mapping with remapping
User namespace remapping maps container root to an unprivileged host user ID.
Step 2: Effect on file ownership visibility
Root-owned files on host appear owned by the mapped unprivileged user inside container.
Final Answer:
The container user is mapped to a non-root user, so root-owned files appear as owned by an unprivileged user -> Option D
Quick Check:
Root remapped to unprivileged user = The container user is mapped to a non-root user, so root-owned files appear as owned by an unprivileged user [OK]

Quick Trick: Root in container maps to unprivileged user on host [OK]

Common Mistakes:

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