Ubuntu 20.04 LTS Docker Permission Denied on /var/run/docker.sock

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

Docker commands fail for operators without root privileges.

Environment & Reproduction

Ubuntu 20.04 LTS with Docker Engine installed and standard user accounts.

Root Cause Analysis

User lacks group membership or socket permissions for Docker daemon API.

Quick Triage

Check docker group membership and current login session group context.

Step-by-Step Diagnosis

Review socket ownership, daemon status, and effective user groups.

Solution – Primary Fix

Add user to docker group and refresh session group mappings.

Solution – Alternative Approaches

Use rootless Docker mode for reduced privilege daemon access.

Verification & Acceptance Criteria

docker ps works without sudo for approved operational accounts.

Rollback Plan

Remove user from docker group if privilege exposure is unacceptable.

Prevention & Hardening

Restrict docker group membership and audit daemon access periodically.

Related Errors & Cross-Refs

Related to cgroup driver mismatch and container runtime startup failures.

Related tutorial: View the step-by-step tutorial for Ubuntu 20.04 LTS.

View all Ubuntu 20.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Consult Docker post-install docs and Ubuntu container hardening guidance.