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Docker

DCA · Question #8

Which of the following namespaces is disabled by default and must be enabled at Docker engine runtime in order to be used?

The correct answer is A. user. User namespaces are disabled by default in Docker and must be explicitly enabled at runtime to remap user IDs for enhanced security.

Submitted by akirajp· Apr 18, 2026Security

Question

Which of the following namespaces is disabled by default and must be enabled at Docker engine runtime in order to be used?

Options

  • Auser
  • Bpid
  • Cnet
  • Dmnt

How the community answered

(26 responses)
  • A
    92% (24)
  • C
    4% (1)
  • D
    4% (1)

Why each option

User namespaces are disabled by default in Docker and must be explicitly enabled at runtime to remap user IDs for enhanced security.

AuserCorrect

User namespaces (`userns`) are disabled by default in Docker and must be explicitly enabled at daemon startup (e.g., with `--userns-remap`) to remap container UIDs/GIDs to different IDs on the host, enhancing security by limiting container process privileges.

Bpid

PID namespaces are enabled by default to ensure containers have an isolated process tree.

Cnet

Network namespaces are enabled by default to provide network isolation for each container.

Dmnt

Mount namespaces are enabled by default to isolate the filesystem mount points for containers.

Concept tested: Docker User Namespace security configuration

Source: https://docs.docker.com/engine/security/userns-remap/

Topics

#Linux Namespaces#User Namespaces#Docker Security#Daemon Configuration

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