Monit vs runit

Monit is a free, open-source utility for managing and monitoring Unix systems, available for Linux, macOS, and self-hosted deployment. It watches local daemon processes and can restart a stopped process or stop one using too many resources. It 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 actions or alerts based on exit values. Monit tracks CPU, memory, system load, and network interfaces, and sends customizable error alerts to syslog or its own log. Its HTTP(S) interface displays service status and allows process control and monitoring changes. It works with init, upstart, and systemd, can use existing run-level scripts, and can run as PID 1 in containers. The maker says it uses statically linked OpenSSL 3.5.7 and dynamically linked PAM support.

runit is a free Unix init scheme that supervises services and can replace sysvinit or other init schemes. It runs on GNU/Linux, BSD systems, MacOSX and Solaris, and can be adapted to other Unix operating systems. As process 1, it manages boot, normal operation and shutdown in three stages. The runsv component launches a service's run program and restarts it if it exits; an optional finish program and log service can also be used. The sv utility reports status and provides controls to start, stop, restart, pause or signal supervised services. For logs, svlogd can filter messages and write automatically rotated logs. The chpst utility changes process state and sets limits for resources such as memory, open files, process count, output size, core size and CPU time. runsvdir can start and monitor runsv processes for up to 1,000 service subdirectories. runit can supervise services alongside an existing init scheme without replacing it. The maker provides source and installation instructions, including manual installation without root access. Its documentation warns that UDP logging is unreliable and should be confined to private networks.