RAFT Consensus Algorithm for Log Replication

Projec for the Distributed Algorithm class at EPITA.

Authors:

• Mehdi Bekhtaoui
• Axen Georget
• Brieg Oudea
• Mickael Gandon

Supervised by:

• Etienne Renault

1. Requirements

To use this project you should install MPI, to do so you should install the libopenmpi-dev package. Along with that this project requires cmake and a C++ compiler supporting the C++17 version. This project also uses the tool make.

2. Build

In order to build this project you can run the following command, it will create a directory call build and add the executable inside:

make

If you want to create a debug environment you can run the following command:

make debug

3. Run the Program

To run the program you can use the run.sh script by executing the following commands:

chmod +x run.sh
./run.sh [client_count] [server_count] [generate_command_list]

Here is a quick description of the parameters:

• client_count: Number of client instances to create
• server_count: Number of client instances to create
• generate_command_list: (yes or no) if yes it will generate a random command list which will be given to the clients

The program will create one file per server containing the replicated log. Those files are named log[rank_of_server].txt.

3.1 Controller Commands

When running you can interact with the controller, here is the list and descriptions of the available commands:

• help: print the help message
• list_ranks: print the list of ranks with the type of the process associated
• entry [client_rank] [command]: send an entry to the client_rank
• start [client_rank]: start the client_rank
• wait_finish [client_rank]: wait that a client has send all his messages
• timeout [server_rank]: simulate an election timeout on the server_rank (force to be candidate)
• get_state [server_rank]: get the state of the server_rank
• print_local_log [server_rank]: print the local log of the server_rank
• set_speed [process_rank] [speed]: set the speed of the process_rank, speed available: {low, medium, high}
• crash [process_rank]: crash the process_rank
• recover [process_rank]: recover the process_rank
• stop [process_rank]: stop the process_rank
• sleep [milliseconds]: sleep the current process for milliseconds

4. Run the Test Suite

In order to run the test suite you can run the following command:

make test

5. Debug the Program

When building the program in debug mode, it will automatically create one debug file per server instance. Those files are located in the folder debug. You can also use the python script tests/merge_log.py this way:

python3 tests/merge_log.py

This script will create a file debug/merged.txt containing all the debug log merged and sorted by timestamp.