mediumIntermediateSymptom-first#cron#scheduler#systemd#crontab#mail

Cron jobs not executing — cron daemon down or misconfigured

Scheduled cron jobs are not running at the expected time

Likely source:availabilityconfiguration

Focused incident mode — strips away everything but this runbook.

Symptoms

  • Scheduled cron jobs are not running at the expected time
  • No cron mail output even though the job should produce output
  • System reboot and cron jobs did not resume

Evidence to grab

Collect these artifacts before you change anything — they prove (or rule out) each cause.

  • Cron service status

    systemctl status cron 2>/dev/null || systemctl status crond 2>/dev/null

  • User crontab

    crontab -l -u <user>

Diagnostic flow

Run the steps in order, marking each claim confirmed or refuted. The evidence you gather feeds the ranked causes below.

Guided decision tree is ready.

Steps with commands, expected output, and pass/fail branches.

Ranked root causes

Evidence checklist

  • systemctl status shows cron is inactive/dead
  • No CRON entries in syslog or journal

Confirm before fixing

systemctl is-active cron 2>/dev/null || systemctl is-active crond 2>/dev/null
READ

Check cron service state

Fix

systemctl start cron && systemctl enable cron
CHANGE

Start and enable the cron daemon

Resolution runbook

Apply from top to bottom after the cause is confirmed. Review every command before running it — risk tags are shown on each.

1
systemctl status cron 2>/dev/null || systemctl status crond 2>/dev/null
READ

Check if cron is running

2
crontab -l -u <user> 2>/dev/null
READ

Verify the crontab entries

3
grep CRON /var/log/syslog 2>/dev/null || journalctl -u cron --since '1 hour ago'
READ

Check cron execution logs

4
systemctl restart cron && systemctl enable cron
CHANGE

Start and enable cron if it was down

Prevention

  • Ensure cron daemon is enabled at boot (systemctl enable cron).
  • Always include PATH in crontab files so scripts can find binaries.
  • Use /etc/cron.d/ for system-level jobs and crontab -e for user-level jobs.
  • Test cron jobs manually with the exact command before adding to crontab.

Related runbooks

Same stack, same failure family — worth a skim.

Systemd service fails to start — unit enters failed statehigh

systemctl status <service> shows failed state

LinuxFoundation3 causes
Open runbook

Commands marked READ CHANGE DESTRUCTIVE — never run DESTRUCTIVE commands against production data you cannot restore. Copy → verify → execute.