Ruby Gem Build "make: command not found" in CI

mkmf generated a Makefile for the gem’s extension, but there is no make on the runner to execute it. The build cannot proceed without the make utility, distinct from a missing compiler.

What this error means

A native gem build fails right after "creating Makefile" with "make: command not found" (or "sh: make: not found"). extconf succeeded; only the make step has nothing to run it.

build output

creating Makefile

current directory: /usr/local/bundle/gems/byebug-11.1.3/ext/byebug
make: command not found

An error occurred while installing byebug, and Bundler cannot continue.

Common causes

make not installed on a slim image

Minimal and Alpine images omit make to stay small. mkmf can still write a Makefile, but there is no make binary to run it.

Compiler present but make missing

An image may ship a compiler without the full build toolchain, so the configure step passes but the make step fails for lack of make.

How to fix it

Install the build toolchain (includes make)

Terminal

# Debian/Ubuntu
apt-get update && apt-get install -y build-essential
# Alpine
apk add --no-cache build-base make
# RHEL/Fedora
dnf groupinstall -y "Development Tools"

Avoid the build with a precompiled gem

If the gem ships a platform build, lock the Linux platform so no make is needed.