Monit
What it is
Monit is a free, open-source utility for monitoring and managing Unix systems, available for Linux and macOS in self-hosted deployments. It watches local daemon processes and can restart a process that stops or stop one using too many resources. It also checks files, directories, and filesystems for timestamp, checksum, or size changes, and tests TCP, UDP, and Unix domain sockets using protocols such as HTTP and SMTP. Scheduled program or script checks can trigger an action or alert based on their exit value. Monit tracks CPU, memory, system load, and network interfaces, and can send customizable error alerts to syslog or its own log. A built-in HTTP(S) interface displays service status and lets users start, stop, or restart processes and enable or disable monitoring. Monit works with init, upstart, and systemd, and can use existing run-level scripts. In containers, it can run as PID 1, combining init duties with service monitoring. The maker says process I/O activity metrics normally require Monit to run as root.
For and against
For
- Monitors processes and can restart or stop them
- Checks filesystems and TCP, UDP, and Unix sockets
- Tracks CPU, memory, system load, and interfaces
- Built-in HTTP(S) interface for service control
Against
- Process I/O metrics normally require root access
- The maker does not answer support questions sent directly to the company
The verdict
Monit combines system checks, alerts, and process control in a free open-source utility. Its process I/O monitoring has a root-access requirement, and support questions are directed to the community mailing list.
Who it suits
Monit suits administrators seeking self-hosted monitoring and automated actions for Unix processes, filesystems, network checks, and system resources. It can also fit container setups that need an init process alongside service monitoring.
Plans and prices
Monit
Free open-source software · GNU Affero General Public License (AGPL)
Read 7 Oct 2026 · mmonit.com
On the record
- Alerts
- Monit sends customizable alert messages about error conditions and can log to syslog or its own log file.mmonit.com · read 7 Oct 2026
- Container use
- Monit can run as PID 1 in containers, handling init responsibilities and service monitoring in one lightweight package.mmonit.com · read 7 Oct 2026
- Filesystems
- It monitors files, directories, and filesystems for timestamp, checksum, or size changes.mmonit.com · read 7 Oct 2026
- Integrations
- Monit works with init, upstart, and systemd and can use existing run-level scripts to manage services.mmonit.com · read 7 Oct 2026
- Network checks
- It supports TCP, UDP, and Unix domain socket checks, with built-in protocol tests such as HTTP and SMTP.mmonit.com · read 7 Oct 2026
- Notable limit
- The maker says process I/O activity metrics normally require Monit to run as root.mmonit.com · read 7 Oct 2026
- Processes
- It monitors local daemon processes and can restart a process that stops or stop one that uses too many resources.mmonit.com · read 7 Oct 2026
- Purpose
- Monit is an open-source utility for managing and monitoring Unix systems, with automatic maintenance and repair actions for errors.mmonit.com · read 7 Oct 2026
- Scripts
- It can run scheduled program or script checks and take action or send an alert based on the exit value.mmonit.com · read 7 Oct 2026
- Security
- The maker says Monit is built with OpenSSL 3.5.7 statically linked and PAM support dynamically linked.mmonit.com · read 7 Oct 2026
- Support
- The maker directs questions to the community mailing list and says it does not have time to answer support questions sent directly to the company.mmonit.com · read 7 Oct 2026
- System metrics
- It can monitor system resources including CPU, memory, system load, and network interfaces.mmonit.com · read 7 Oct 2026
- Web interface
- Its built-in HTTP(S) interface shows monitored service status and lets users start, stop, or restart processes and enable or disable monitoring.mmonit.com · read 7 Oct 2026
