Cron Job Does Not Execute at Scheduled Time

📖 ~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

Cron runs with minimal environment and strict timing semantics.

Environment & Reproduction

Expected task output is missing and no recent run artifacts appear.

Root Cause Analysis

User or system crontabs with relative paths or unmet runtime dependencies.

Quick Triage

Syntax issue, wrong interpreter, permission error, or timezone mismatch.

Step-by-Step Diagnosis

Collect crontab lines, syslog entries, and script execution logs.

Solution – Primary Fix

Use absolute paths, explicit shell, and corrected schedule expression.

Solution – Alternative Approaches

Standardize job wrappers with logging, locking, and health checks.

Verification & Acceptance Criteria

Run job manually and confirm scheduled execution in next interval.

Rollback Plan

Validate cron syntax in CI and test scripts under cron-like environment.

Prevention & Hardening

Alert when expected job heartbeat file is stale.

Related Errors & Cross-Refs

Restore previous crontab version and script wrapper if change regresses.

Related tutorial: View the step-by-step tutorial for debian-10.

View all debian-10 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

cron and crontab man pages for Debian systems.