Solar container debugging tool

How do I debug a guinea pig container (distroless)?

F.A.Q

How does debug shell work?

Debug Shell automatically asks you to install commands the first time you try to run them: Since it's is an "overlay" on top of the container, it doesn't modify the actual container or image at all, and works on read-only containers. All the extra tools work exactly as if they were running directly in your container.

Where can I find debugging tools?

The debugging tools are available in the target container. By default, the busybox:musl (statically compiled) image is used for the debugger sidecar, but you can override it with the --image flag. Combining this with the superpower of Nix and Nixery, you can get all your favorite tools by simply listing them in the image name:

How do I debug a guinea pig container (distroless)?

Start the guinea-pig container (distroless): -v $(pwd)/debugger:/.debugger \ --name my-distroless gcr.io/distroless/nodejs \ -e 'setTimeout(() => console.log("Done"), 99999999)' # 3. Start the debugging session: The above docker exec command will place you right into the target container (i.e, all its namespaces will be shared).

Can nixery debug images?

Not every image can be used for debugging - the statically linked tools (like busybox) or Nix-based distros expectedly work the best. Installing extra tools on demand will likely be problematic Nixery.dev fixed it for me. Mounting the debugging tools into the target container requires a restart.

How can I build a container from a distroless image?

The approach doesn't work with distroless images since there is no shell or package manager inside. The second most obvious solution is to temporarily switch to another base image. Instead of using debian:stable-slim, you can build a container from the regular debian:stable base image that has more tools preinstalled.

How do I get a debug shell inside a Linux container?

To get a debug shell inside, run: The debug shell allows you to inspect the filesystem: dev etc hello nix proc sys The file /hello is the binary that was executed when running the container. You can confirm this by running it directly: After running the binary, it produces the same output.