A mini container runtime implementation in Odin, inspired by runc. This project provides basic container management functionality including create, start, list, delete, and exec operations.

• Yggdrasil: 473 KB (0.5 MB) - 122x smaller than Docker!
• runc: 13.5 MB - 28x larger than Yggdrasil
• Docker: 55.2 MB - 117x larger than Yggdrasil

• ✅ Create containers with custom rootfs and commands
• ✅ Start containers in background mode
• ✅ Stop containers with graceful shutdown
• ✅ List containers with status and process information
• ✅ Delete containers and clean up resources
• ✅ Execute commands in running containers (interactive shell support)

• ✅ Linux namespaces (PID, mount, UTS, network)
• ✅ Overlay filesystem support for rootfs isolation
• ✅ chroot filesystem isolation
• ✅ Process isolation with fork/exec
• ✅ Root privilege checking with helpful error messages

• ✅ Container state persistence using state files
• ✅ Background container execution (daemon mode)
• ✅ Process monitoring and automatic status updates
• ✅ Container lifecycle management

• ✅ Simple command-line interface
• ✅ Helpful usage messages
• ✅ Error handling with clear feedback
• ✅ Status reporting for all operations

• Odin compiler (https://odin-lang.org/docs/install/)
• Linux system with kernel support for namespaces
• Root filesystem image (e.g., Alpine Linux)
• Root privileges (required for namespace operations)

./build.sh

This will create a yggdrasil binary in the current directory.

./ygg create mycontainer --rootfs ./rootfs --hostname myhost -- /bin/sh

Options:

• --rootfs <path>: Path to root filesystem (default: ./rootfs)
• --hostname <name>: Container hostname
• --net <mode>: Network mode - host|none (default: host)
• -- <command>: Command to run in container

sudo ./ygg start mycontainer

sudo ./ygg stop mycontainer

./ygg ps

# Execute a single command
sudo ./ygg exec mycontainer /bin/ls

# Get interactive shell (like docker exec -it)
sudo ./ygg exec mycontainer /bin/sh

./ygg delete mycontainer

• Created: Container configuration created but not started
• Running: Container is currently running
• Stopped: Container has finished execution
• Deleted: Container has been removed

The runtime uses several Linux features:

1. Namespaces: Process, mount, and network isolation
2. Overlay filesystem: Union mount for rootfs protection
3. chroot: Change root directory for container filesystem
4. fork/exec: Process management and command execution

Yggdrasil/
├── main.odin          # Main runtime implementation
├── build.sh           # Build script
├── README.md          # This file
├── rootfs.gz          # Root filesystem image
└── containers/        # Container state directory (created at runtime)
    └── *.json         # Container state files

1. Prepare rootfs:

   # Download Alpine Linux rootfs
   wget https://dl-cdn.alpinelinux.org/alpine/latest-stable/releases/x86_64/alpine-minirootfs-3.22.0-x86_64.tar.gz
   tar -xzf alpine-minirootfs-3.22.0-x86_64.tar.gz
   mv alpine-minirootfs-3.22.0-x86_64 rootfs

2. Create and start container:

   ./ygg create test --rootfs ./rootfs -- /bin/sleep 3600
   sudo ./ygg start test  # Requires root privileges

3. List containers:

   ./ygg ps

4. Execute commands in container:

   sudo ./ygg exec test /bin/ls
   sudo ./ygg exec test /bin/sh  # Interactive shell

5. Stop and clean up:

   sudo ./ygg stop test
   ./ygg delete test

• No TTY support (containers run without terminal)
• Basic namespace joining (exec uses chroot instead of setns)
• No resource limits or cgroups
• No advanced networking configuration
• No image management (requires manual rootfs setup)
• No security profiles or seccomp
• No volume mounts or bind mounts
• No container orchestration features

• This is a learning project and should not be used in production
• Containers run with the same privileges as the host
• No security isolation beyond basic namespaces
• Always run in a safe environment for testing

This project is for educational purposes. Use at your own risk.