Cron — alert when a scheduled job did not run
cron is alive, but the job (timer disabled, MAILTO=root spam, sh-syntax-error in crontab) did not run last night. The classic "we forgot last night gave empty reports".
Recipe
#!/usr/bin/env bash
# /etc/cron.d/cron-skipped
# Run this at the END of the cron job you want to monitor:
# 30 3 * * * root /opt/some-job.sh && /opt/cron-ping.sh some-job
# /opt/cron-ping.sh — sends success ping with name
NAME=${1:?usage: cron-ping.sh <job-name>}
curl -fsS "$HEARTBEAT_URL/cron/$NAME" --data "ts=$(date +%s)"
# A separate guard runs at 03:45 (15 min AFTER the expected window)
# and complains if no ping arrived. That's a "dead-man's switch" —
# if the monitor itself has retention you need NOTHING ELSE on the box:
# 45 3 * * * root /opt/cron-watchdog.sh some-jobSame thing in Enterno.io
Use Enterno heartbeat in expected-schedule mode — it understands "should have arrived by 03:30" and alerts if the ping is late beyond the grace period. No second watchdog cron needed on the box.
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