Affected versions: 20.04 LTS

πŸ“– ~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

Security patches stop applying automatically, increasing vulnerability exposure and creating compliance reporting gaps.

Environment & Reproduction

Occurs when key packages are manually held, pin priorities conflict, or dependency chains require interactive resolution.

Root Cause Analysis

unattended-upgrades cannot resolve package graph changes when version holds block required dependency transitions.

Quick Triage

Review unattended-upgrades logs, identify held packages, and assess whether holds are still operationally necessary.

Step-by-Step Diagnosis

Run apt-mark showhold, simulate upgrades, and inspect policy priorities for blocked dependency paths.

Illustrative mockup for ubuntu-20-04-lts β€” unattended_upgrade_problem
Automatic upgrade reports package hold conflict β€” Illustrative mockup β€” Progressive Robot

Solution – Primary Fix

Clear obsolete holds, adjust pinning strategy, repair package state, and re-run unattended-upgrades with validation.

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Illustrative mockup for ubuntu-20-04-lts β€” held_package_resolution_fix
Resolved holds and successful unattended upgrade β€” Illustrative mockup β€” Progressive Robot

Solution – Alternative Approaches

Move sensitive packages to managed maintenance windows or use phased rollout tooling for controlled version adoption.

Verification & Acceptance Criteria

Automatic upgrade cycles should complete successfully and include expected security updates without manual intervention.

Rollback Plan

Reapply temporary package holds if critical compatibility issues emerge, with explicit expiration and review dates.

Prevention & Hardening

Track hold rationale in change records and monitor unattended-upgrades health to prevent silent patching drift.

Related incidents include apt lock contention, signature errors, and dependency breakage during major repository transitions.

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

View all Ubuntu 20.04 LTS tutorials on the Tutorials Hub β†’

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

See unattended-upgrades docs, apt pinning references, and Ubuntu security patch management best practices.

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