goss-org/goss

Goss is a command-line tool for checking that a server is configured the way you expect. Rather than logging into a machine and manually verifying that a service is running, a port is open, or a user account exists, you write a YAML file that describes what the correct state should look like, and Goss checks it all at once. If something is wrong, you get a list of failures. The tool is designed to be fast. Small test suites finish in under a second, and the binary itself is under 10 MB with no dependencies to install alongside it. You can download a single file and run it. One of its most useful features is auto-generation. Instead of writing the YAML by hand from scratch, you point Goss at a running process or service and it inspects the system to generate a test file that matches the current state. For example, running the autoadd command against sshd produces a YAML file that captures the port it listens on, whether the service is enabled and running, the user account it uses, and more. You then use that file as your baseline and can modify it if you want to add more specific checks. Goss can also run as a health endpoint. In server environments where an external system needs to poll whether a machine is ready, Goss can serve a small HTTP endpoint that returns pass or fail based on whether all the tests in its YAML file succeed. This makes it useful for container startup checks in Docker or similar environments, where the platform needs a way to know when a container has finished starting before sending it traffic. Tests can use variables and templates, which lets you write a single test file that behaves differently depending on the environment or operating system. The test file format has a published schema so editors can provide autocomplete and validation while you write checks. Installation is a single curl command or a manual binary download from the releases page. There are also wrapper scripts for testing Docker containers and Kubernetes environments.