🟡 Medium   ⏱ 5–30 min  Last verified: 19 May 2026

📖 ~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

A required service fails at startup, causing application outage or degraded host functionality.

Environment & Reproduction

Ubuntu 18.04 using systemd units for web, database, or custom app daemons.

Root Cause Analysis

Invalid unit directives, missing executable paths, permission issues, or unsatisfied service dependencies.

Quick Triage

Run systemctl status and journalctl -u -n 100 –no-pager for immediate failure context.

Step-by-Step Diagnosis

Validate unit syntax with systemd-analyze verify, inspect ExecStart path, and confirm required environment files exist.

Illustrative mockup for ubuntu-18-04-lts — ubuntu1804-systemd-service-failed-diagnose.webp
Using systemctl and journalctl to inspect failed units — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Fix unit file or dependency order, run sudo systemctl daemon-reload, then restart and enable the service.

Still having issues? Our IT Solutions & Services team can diagnose and resolve this for you. Get in touch for a free consultation.

Illustrative mockup for ubuntu-18-04-lts — ubuntu1804-systemd-service-failed-fix.webp
Correcting unit files and restarting services cleanly — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Use drop-in overrides under /etc/systemd/system/.d to avoid editing vendor unit files directly.

Verification & Acceptance Criteria

systemctl is-active returns active, logs are clean of repeated failures, and dependent services start normally.

Rollback Plan

Restore previous unit file from backup and reload daemon to return to known-good behavior.

Prevention & Hardening

Version-control unit files, add health checks, and configure Restart policies with sensible backoff.

Main process exited, failed with result exit-code, and dependency failed for target messages.

Related tutorial: View the step-by-step tutorial for Ubuntu 18.04 LTS.

View all Ubuntu 18.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

man systemd.service, man journalctl, and systemd.unit documentation.

Need Expert Help?

If you cannot resolve this yourself, our team offers hands-on Server Management, Managed IT Services, and flexible Support Plans. Contact us today — we respond within one business day.