Using rbspy


rbspy has three subcommands: snapshot, record, and report.

snapshot takes a single stack trace from the specified process, prints it, and exits. This is useful if you have a stuck Ruby program and just want to know what it's doing right now.

record continuously captures stack traces from your process and saves them to disk. It's used to profile a program over a period of time and to produce a flamegraph or other output for offline analysis.

report is useful if you have a raw rbspy data file that you've previously recorded. You can use rbspy report to generate different kinds of visualizations from it, as documented in the record section. This is useful because you can record raw data from a program and then decide how you want to visualize it afterwards.


If you want to profile a ruby program that's running in a container on Linux, be sure to add the SYS_PTRACE capability.

For Docker containers, this can be done by adding a flag to the command when you launch the container:

docker run --cap-add=SYS_PTRACE ...

If your Docker containers start up through Docker Compose, you can add the flag to the relevant container(s) in docker-compose.yml:

      - SYS_PTRACE

If you're using Kubernetes, you can add the ptrace capability to a deployment like this:

      - SYS_PTRACE

If this doesn't work for you, see issue 325 for troubleshooting steps. You may need additional securityContext configuration if the processes in your container are running as an unprivileged (non-root) user, which is recommended for security reasons.