Systemd Service Fails At Boot But Works Manually

📖 ~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 unit fails during boot, but `systemctl start` works after login on RHEL 9.

Environment & Reproduction

Run `systemctl status ` and `systemctl is-enabled ` to verify enablement and immediate errors.

Root Cause Analysis

Check package ownership of the unit file with `rpm -qf /usr/lib/systemd/system/.service`.

Quick Triage

Use `systemctl cat ` and `systemctl show -p After,Requires,Wants ` for ordering diagnostics.

Step-by-Step Diagnosis

Inspect boot-specific output via `journalctl -b -u ` and dependency failures around startup.

Solution – Primary Fix

Archive drop-ins from `/etc/systemd/system/.service.d/` before modifications.

Solution – Alternative Approaches

If network dependent, validate `After=network-online.target` and relevant `firewalld` readiness.

Verification & Acceptance Criteria

Confirm executable and config contexts are correct with `ls -Z` and `restorecon` if required.

Rollback Plan

Adjust dependencies, add restart policy, run `systemctl daemon-reload`, and re-enable the unit.

Prevention & Hardening

Reboot and verify healthy startup using `systemctl –failed` and `journalctl -b`.

Related Errors & Cross-Refs

Version-control unit overrides and test boot order changes in staging first.

Related tutorial: View the step-by-step tutorial for rhel-9.

View all rhel-9 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Share unit file, override files, and `systemd-analyze critical-chain` output.