Cute Cluster Chess

Cute Cluster Chess (CCC) is a Chess Engine Testing Framework for Linux.

CCC creates a cluster of Linux nodes on an intranet and uses ssh key sharing to access individual nodes. But don't worry, the configuration is very simple and is automatic through a web interface. The nodes must already have git and an ssh server installed (on Ubuntu you can install this with sudo apt install openssh-server). Instead, git, Python 3 and sshpass must be installed on the master node.

How does it work.

On the GitHub repository of your chess engine there must be a branch named base, it will be the stable version of your engine that you want to improve, then create other branches with the changes to test, these branches must begin with the prefix _test_/ for example: do you want to test a change to null moves? and one to the quiescence function? then create 2 branches _test_/null and _test_/qs you can create as many branches as you want. CCC will automatically download these branches and will start playing them against the "base" version through cutechess-cli.

CCC uses crontab to check if there are branches to test (this check is suspended during testing).

Caveats

Before launching CCC, verify that python 3, sshpass and git are installed on the master node with:

python --version

sshpass -V

git --version

and check that git is installed on the nodes and sshd is active (just launch ssh {user}@{ip_node} from the master node if it asks you for the password and is configured correctly).

If your GitHub repository is private verify that individual nodes and the master node can clone your repository.

Let's go

On the master node download the source code start the server passing random login/password:

git clone [email protected]:gekomad/cute_cluster_chess.git
cd cute_cluster_chess/web
./server.py {login} {pass}

open your browser to the page http://{ip_master}:8395 enter {login} {pass}

At the first start, only the Settings tab will be shown. Fill in these fields:

• GitHub repository: it is the repository of your chess engine (it must start with [email protected]:... and not with https://github.com...)
• Opening epd file: select the file with the openings you see under cute_cluster_chess/epd, you can add your files and restart the server.
• Resign: is the Resign parameter of cutechess-cli.
• Draw: is the draw parameter of cutechess-cli.
• Time Control: is the tc parameter of cutechess-cli.
• Hash size: it is the size in MB of the hash table.
• Concurrency: it is the Concurrency parameter of cutechess-cli, it indicates how many instances of cutechess-cli will be launched in parallel.
• Variant: is the Variant parameter of cutechess-cli.
• Tot Games: is the number of games for each node
• Path to compile: the folder from which to launch the compilation command, if you use make it is probably src if you use rust it is probably .
• Build command x86_64: you can leave it blank. is the command to generate the executable for the x86_64 architecture, it could simply be make, or cmake CMakeLists.txt && make or cargo build --release. Remember the compiler must be present on the various nodes (gcc, g++, cardo, rustc, cmake, make, etc).
• Build command aarch64: you can leave it blank, as above but for the aarch64 architecture. At least one of the two previous fields must be completed.
• exe Relative Path: it is the path of the executable starting from the root of the project, if your sources are in the src folder and you use the make command to compile the path will be src/engine_name, if your engine it is written in rust probably the path will be target/release/engine_name.
• First param: is the cutechess-cli option.FOO=BAR parameter of the first engine.
• Second param: is the cutechess-cli option.FOO=BAR parameter of the second engine.

Add nodes

• After configuring go to the 'cluster' tab and click on Add new, then enter:

• ip/host: is the address of the insurance node that can be reached via ssh

• user: this is the linux user, it might be a good idea to create a specific user for CCC

• port: it is the ssh port, you can leave it blank

• password: it is the password of the linux user. The password will be used to connect via ssh to the node and add the ssh key in this mode the master node will be able to access the node without a password. The password will not be stored.

• CPU: indicates how many CPUs will be dedicated to tests.

Click Add Node

insert as many nodes as you want. Finally click on Start All

The Tests tab indicates the currently active tests.

Uninstall nodes

• go to the Cluster tab and click Remove node, this will delete the ~/cute_cluster_chess_node folder.
• on the node run crontab -e and delete the line relating to CCC.
• on the node open the file ~/.ssh/authorized_keys and delete the name relating to the master, in this way the master will have to enter the password again in order to access the node via ssh.