Snapped

Snapped is a parallel program snapshotter designed for debugging deadlocks and crashes in programs. It acts as a wrapper around the GDB Machine Interface (GDB-MI), leveraging the capabilities of GDB to provide robust debugging features. Snapped is implemented in Rust.

Features

• Direct Debugging: Snapped allows you to directly debug a program by taking snapshots at the point of failure.
• Parallel Debugging: Designed to handle parallel processes, Snapped can connect to thousands of processes using a tree-based overlay network, making it suitable for debugging distributed applications.

Installation

Before using Snapped, you need to ensure that you have Rust installed. If you haven't installed Rust yet, you can do so by following these steps:

Install Rust using rustup

1. Install rustup by executing the following command in your terminal:

   curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

2. Follow the on-screen instructions to complete the installation.
3. Add rustup to your system's PATH by sourcing the cargo environment variables:

   source $HOME/.cargo/env

Build and Install Snapped

Once Rust is installed, you can build and install Snapped:

git clone https://github.com/besnardjb/snapped
cd snapped
cargo build --release

The snapped binary will be located in the target/release directory.

Build a LibC independent version

If you need to deploy on a machine quickly without building remotely you may build a fully static binary using the musl LibC by doing the following:

# Add musl based libc build (static binaries)
rustup target add x86_64-unknown-linux-musl
# Build over static libc
cargo build --target x86_64-unknown-linux-musl --release
# Copy to REMOTE
scp ./target/x86_64-unknown-linux-musl/release/snapped REMOTE:
# Enjoy

Usage

Snapped provides a straightforward interface for debugging your programs. Below are some common usage patterns:

Direct Debugging

To debug a program directly, use the following command:

snapped ./a.out

This command runs the program a.out under Snapped, allowing you to take snapshots for debugging.

Parallel Debugging

For parallel or distributed applications, you can run Snapped in parallel debugging mode:

snapped -p 128 mpirun -np 128 snapped ./a.out

or

snapped -p 128 srun -n 128 snapped ./a.out

In this mode, Snapped acts as a GDB server for each process, allowing for comprehensive debugging across multiple instances. If the program crashes or if you hit CTRL+C once you should get a snapshot of the program state.

Options

Snapped supports several options to customize its behavior:

• -i, --interrupt-after <INTERRUPT_AFTER>
  Interrupt the program after a specified number of seconds. Note CTRL+C (once) will also interupt.

• -r, --root-server <ROOT_SERVER>
  Set up the program to backconnect to a root debugger instance.

• -p, --pivot-processes <PIVOT_PROCESSES>
  Act as a GDB server for debugging parallel processes.

• -h, --help
  Display the help message with all available options.

Contributing

Contributions are welcome! Please feel free to submit a pull request or open an issue on the GitHub repository.

License

ParaTools, All Rights Reserved Contact info@paratools.com for further information