Multi-Paxos Key-Value Store

This is the final project for the undergrad distributed systems class at UCSB. The goal is to implement a distributed key-value application on top of a simple blockchain to create a trusted but fault-tolerant system.
By Xueyi Yao (@xueyiyao) and Justin Dong (@justindong1)

Setup

Servers:

1. Starting the servers:
   Start up 5 terminals, one for each server.

   % python3 server.py <SERVER_ID>
   

   SERVER_ID should be a value from 1 to 5. Each terminal should correspond to a different SERVER_ID

2. Connecting the servers:
   Simply run "c" in each of the server terminals. You should see:

   connecting to other servers
   connected to other servers
   

Clients:

1. Starting the clients: Start up 1-3 terminals, one for each client.

   % python3 client.py <CLIENT_ID>
   

   CLIENT_ID should be a value from 1 to 3. Each terminal should correspond to a different CLIENT_ID. You should get a response:

   checking word for server 1
   checking word for server 2
   checking word for server 3
   checking word for server 4
   checking word for server 5
   

   Congrats! You have successfully setup the servers and the clients!

User Inputs

Servers:

• printBlockchain
  • prints the blockchain for the server to terminal
• printKVStore
  • prints the key-value store for the server to terminal
• printQueue
  • prints the queue for the server to terminal
• failLink(<src>, <dest>)
  • temporarily disables the connection between src server and dest server
  • currently only works if initiated from the src server's terminal
• fixLink(<src>, <dest>)
  • re-enables the connection between src server and dest server
  • currently only works if initiated from the src server's terminal
• failProcess
  • permanently closes connections and closes the server
  • server will need to be restarted to continue working
• reconnect
  • reconnects the server to all other servers
  • OPTIONALLY add servers to not reconnect to
    • "reconnect 1 2" will mean to reconnect to all servers except 1 and 2
• e
  • forcibly closes all connections and exits the server

Clients:

• Operation(put, <key>, <value>)
  • add a key-value pair to the store
• Operation(get, <value>)
  • retrieves a value for a inputted key
• reconnect <SERVER_ID>
  • reconnects client to server with server_id = SERVER_ID
• e
  • forcibly closes connections and exits the client