Battleship

Battleship is a Byzantine fault tolerant prototype of a distributed storage system built on the Raft consensus algorithm. This project was originally forked from Zatt

By default, clients share a dict data structure, although every python object is potentially replicable with the pickle state machine.

Please note that Battleship servers and clients must both be run using python3.

Structure of the project

The most relevant part of the code concerning BFT Raft is in the states and in the log files.

How to run

Spinning up a cluster of servers

A server can be configured with command-line options or with a config file, in this example, we are going to use both.

First, create an empty folder and enter it: $ mkdir zatt_cluster && cd zatt_cluster.

Now create a config file config.json with the following content:

{  
    "StorageDir":"zatt_cluster/storage",
    "keyDir":"zatt_cluster/keys",
    "cluster":[  
       [  
          "127.0.0.1",
          9110

       ],
       [  
          "127.0.0.1",
          9111
       ],
       [  
          "127.0.0.1",
          9112
       ],
       [  
          "127.0.0.1",
          9113
       ]
    ]
 }

You can now descend into the server directory ($cd zatt/server) and run the first node.

$ python3 -c ABSOLUTE_PATH_TO_BATTLESHIP_CONFIG 0

This tells zattd to run the node with id:0, taking the info about address and port from the config file.

You can do the same to run the other three nodes, with ids 1, 2, and 3.

Client

To interact with the cluster, we need a client. Navigate down into the client directory ($cd zatt/client) and open a python interpreter ($ python3) and run the following commands:

In [1]: from distributedDict import createClientDict
In [2]: d = createClientDict('127.0.0.1', 9110, "ABSOLUTE_PATH_TO_CONFIG_FILE")
In [3]: d['key'] = 'value'

Let's retrieve key from a second client:

Open the python interpreter on another terminal and run:

In [1]: from distributedDict import createClientDict
In [2]: d = createClientDict('127.0.0.1', 9111, "ABSOLUTE_PATH_TO_CONFIG_FILE")
In [3]: d['key']
Out[3]: 'value'

Notes

Please note that you may need to remove the persistent storage for the node in order for it to run properly. You can do so by going to the zatt_cluster directory and executing ($ rm -rf storage)

Also note that JSON, currently used for serialization, only supports keys of type str and values of type int, float, str, bool, list, dict .

Tests

In order to run the tests:

• navigate to the test folder: cd zatt/tests
• execute: python3 run.py

If you stop the tests mid-run, be sure to remove any persistent storage output by the tests by typing rm -rf persistentStorage in the tests directory.