Ubuntu 14.04 LTS Cron Jobs Not Running at Scheduled Times

📖 ~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

Backups, reports, and automation tasks silently fail to execute on time.

Environment & Reproduction

Seen after timezone changes, malformed crontab entries, or cron daemon interruption.

Root Cause Analysis

Scheduling parser issues, environment path assumptions, or service downtime block execution.

Quick Triage

Confirm cron service active, inspect syslog entries, and validate crontab syntax.

Step-by-Step Diagnosis

Trace cron logs, test minimal jobs, and review script execution permissions and shebangs.

Solution – Primary Fix

Fix crontab syntax, set explicit PATH/env variables, and restart cron daemon.

Solution – Alternative Approaches

Migrate critical tasks to systemd timers or external scheduler service.

Verification & Acceptance Criteria

Jobs run at expected times and output logs confirm successful completion.

Rollback Plan

Restore prior crontab from backup and disable recently added failing entries.

Prevention & Hardening

Add cron job health checks and alerting for missed execution windows.

Related Errors & Cross-Refs

Linked to NTP drift, permission errors, and shell path misconfiguration.

Related tutorial: View the step-by-step tutorial for Ubuntu 14.04 LTS.

View all Ubuntu 14.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

cron man pages, Ubuntu scheduled task guides, and automation reliability practices.