Project 18: Distributed Key-Value Store with RPC

A multi-server key-value store using RPC for client-server and server-server communication.

Quick Reference

Attribute Value
Primary Language C
Alternative Languages N/A
Difficulty Level 4 (Expert)
Time Estimate See main guide
Knowledge Area Distributed Systems, Storage
Tooling See main guide
Prerequisites See main guide

What You Will Build

A multi-server key-value store using RPC for client-server and server-server communication.

Why It Matters

This project builds core skills that appear repeatedly in real-world systems and tooling.

Core Challenges

  • Identify the tricky edge cases and design for them.

Key Concepts

  • Map the project to core concepts before you code.

Real-World Outcome

# Start 3 server replicas
$ ./kv_server --id=1 --port=9001 --peers=localhost:9002,localhost:9003 &
$ ./kv_server --id=2 --port=9002 --peers=localhost:9001,localhost:9003 &
$ ./kv_server --id=3 --port=9003 --peers=localhost:9001,localhost:9002 &

# Client connects to any server
$ ./kv_client --server=localhost:9001 put mykey "Hello World"
OK (replicated to 3 nodes)

$ ./kv_client --server=localhost:9002 get mykey
Hello World

# Kill a server, data still available
$ kill %1
$ ./kv_client --server=localhost:9002 get mykey
Hello World

Implementation Guide

  1. Reproduce the simplest happy-path scenario.
  2. Build the smallest working version of the core feature.
  3. Add input validation and error handling.
  4. Add instrumentation/logging to confirm behavior.
  5. Refactor into clean modules with tests.

Milestones

  • Milestone 1: Minimal working program that runs end-to-end.
  • Milestone 2: Correct outputs for typical inputs.
  • Milestone 3: Robust handling of edge cases.
  • Milestone 4: Clean structure and documented usage.

Validation Checklist

  • Output matches the real-world outcome example
  • Handles invalid inputs safely
  • Provides clear errors and exit codes
  • Repeatable results across runs

References

  • Main guide: UNIX_IPC_STEVENS_VOL2_MASTERY.md
  • Primary references are listed in the main guide