Systemd Timer Management with Python: List, Audit, and Monitor Timers (Free CLI Tool)

Systemd Timers: The Modern Cron Alternative

Systemd timers have largely replaced cron jobs on modern Linux distributions. They offer significant advantages: journalctl integration for centralized logging, dependency management between services, persistent timers that survive reboots, and resource control via cgroups.

dargslan-systemd-timer is a free Python CLI tool that helps you list, audit, and monitor systemd timers, detect failed timer services, and compare your timer setup with legacy cron jobs.

Install dargslan-systemd-timer

pip install dargslan-systemd-timer

Zero external dependencies. Works on any Linux distribution with systemd.

Timer Report

dargslan-timer report

Shows all active timers with their state, description, and any issues. Also compares systemd timers with existing cron jobs.

List Timers

# Active timers only
dargslan-timer list

# All timers (including inactive)
dargslan-timer list --all

Displays timer units and their associated service units.

Detect Failed Services

dargslan-timer failed

Checks all timer-triggered services for failures. A failed service means the scheduled task did not complete successfully — this requires immediate attention.

Cron Comparison

dargslan-timer cron

Lists current cron entries and compares them with systemd timers. Provides migration recommendations for moving legacy cron jobs to modern systemd timers.

Python API

from dargslan_systemd_timer import TimerManager

tm = TimerManager()

# List all timers
timers = tm.list_timers(all_timers=True)
for t in timers:
    print(f"{t['timer']} -> {t['unit']}")

# Timer status details
status = tm.timer_status("apt-daily.timer")
print(f"State: {status['active']}")
print(f"Description: {status['description']}")
print(f"Next trigger: {status['next_trigger']}")

# Find failed services
failed = tm.check_failed()
for f in failed:
    print(f"FAILED: {f['timer']} -> {f['unit']}")

# Cron comparison
cron = tm.compare_with_cron()
print(f"Timers: {cron['timers']}, Cron jobs: {cron['cron_entries']}")
print(cron['recommendation'])

Systemd Timer vs Cron

Creating a Systemd Timer

Example: Run a backup script daily at 2 AM.

Service Unit (/etc/systemd/system/backup.service)

[Unit]
Description=Daily Backup Script

[Service]
Type=oneshot
ExecStart=/usr/local/bin/backup.sh
User=root

Timer Unit (/etc/systemd/system/backup.timer)

[Unit]
Description=Run backup daily at 2 AM

[Timer]
OnCalendar=*-*-* 02:00:00
Persistent=true
RandomizedDelaySec=300

[Install]
WantedBy=timers.target

Enable and Start

sudo systemctl daemon-reload
sudo systemctl enable --now backup.timer
sudo systemctl list-timers backup.timer

Audit Results

The audit checks for:

• CRITICAL: Failed timer-triggered services
• WARNING: Inactive timers that should be running
• INFO: Cron jobs that could be migrated to timers

Download the Free Cheat Sheet

Get the complete Systemd Timer Cheat Sheet PDF with timer creation templates, CLI commands, and Python API reference.

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