This documentation is for an old GraalVM version. See the latest version.

Installing LibYAML

TruffleRuby requires to have libyaml installed, much like CRuby 3.2+ and Psych 5+.

If you experience psych-related errors saying it cannot find libyaml, it might help to recompile the psych gem by running lib/truffle/ This is done automatically by Ruby managers, and mentioned in the post-install message when installing TruffleRuby via gu install in GraalVM.

Fedora-based: RHEL, Oracle Linux, etc #


sudo dnf install libyaml-devel

Oracle Linux 7

sudo yum install --enablerepo=ol7_optional_latest libyaml-devel

Oracle Linux 8

sudo dnf install --enablerepo=ol8_codeready_builder libyaml-devel

Debian-based: Ubuntu, etc #

sudo apt-get install libyaml-dev

macOS #


We recommend installing libssl via Homebrew.

brew install libyaml


MacPorts should also work but is not actively tested.

sudo port install libyaml

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