systemd vs BusyBox init: Which Init System Fits Your Device?
For most embedded products with a fixed set of services and no user-installable software, BusyBox init is the right default: small, no dependency chain, and its behaviour fits in one readable file. Choose systemd when the device genuinely needs supervised, interdependent services — readiness ordering, watchdog-backed liveness detection, resource limits — and accept in return a much larger image,…
When designing embedded Linux products, one of the most critical decisions is choosing between systemd and BusyBox init. BusyBox init is a small, dependency-free option that is ideal for devices with a fixed set of services and no user-installable software. It is easy to read and maintain, with its behavior contained in a single file.
BusyBox init uses /etc/inittab for configuration, with entries specifying the service ID, runlevels, action, and process to be executed. However, it lacks the advanced features of systemd, such as readiness ordering, watchdog-backed liveness detection, resource limits, and dependency tracking.
On the other hand, systemd is a comprehensive init system that offers advanced features like interdependent service management, readiness ordering, watchdog-backed liveness detection, and resource limits. It operates with a larger image size and a kernel floor of 5.10. Choosing systemd requires accepting a much larger image, maintaining a dependency set for the product's lifetime, and using a glibc toolchain if built with Buildroot.
The decision of systemd vs BusyBox init is one of the most important and challenging decisions in an embedded Linux product, as it affects how services declare dependencies, how failures are detected, and which libraries remain in the image forever.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
