Ubuntu 20.04 LTS – Docker daemon fails to start after package updates

📖 ~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

Containers stay down because dockerd exits during startup.

Environment & Reproduction

Usually after daemon config changes, cgroup mismatch, or storage driver issues.

Root Cause Analysis

Docker service dependencies or configuration are incompatible with current host state.

Quick Triage

Check docker.service status, unit logs, and daemon.json syntax.

Step-by-Step Diagnosis

Inspect journal errors and validate cgroup and storage driver compatibility.

Solution – Primary Fix

Correct daemon configuration, restart dependencies, and relaunch Docker service.

Solution – Alternative Approaches

Pin known-stable Docker package version until compatibility is validated.

Verification & Acceptance Criteria

docker info succeeds and required containers restart cleanly.

Rollback Plan

Revert docker packages and configuration to last-known-good snapshot.

Prevention & Hardening

Test daemon updates in staging and validate config changes with CI checks.

Related Errors & Cross-Refs

Failed to start Docker Application Container Engine and cgroup driver mismatch.

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

Docker on Ubuntu 20.04 installation and daemon troubleshooting docs.