COUBES

COUBES (Container Orchestration Universal Benchmark for Evaluating Schedulers) is a framework that integrates CloudSim 7G with lightweight Kubernetes clusters to enable reproducible, multi-metric benchmarking of container orchestration schedulers.

This repository contains the current proof-of-concept implementation, developed as part of an MSci Project (2024–2025). It will transition towards a more mature and extensible version at a later date.

Overview

The aim of COUBES is to provide a universal testing harness for Kubernetes schedulers using CloudSim. However, instead of re-implementing the scheduling logic inside CloudSim, COUBES delegates scheduling decisions to a live Kubernetes scheduler via an adapter layer.

• A custom CloudSim broker, Live_Kubernetes_Broker_EX extends the default DatacentreBrokerEX.
• The broker forwards CloudSim resources (VMs and Cloudlets) to an adapter written in Go. This can be found in the k8s-cloudsim-adapter folder.
• The adapter translates these into Kubernetes equivalents (Nodes and Pods), using KWOK for lightweight cluster emulation.
• The native Kubernetes scheduler performs scheduling as usual.
• Results are returned from KWOK to the adapter, then mapped back into CloudSim’s resource model so the simulation can proceed.

Current Status

Last update: 29/08/2025

• Currently supports basic scenarios with the Kubernetes Default Scheduler.
• Implements a scoring system for comparing schedulers across multiple metrics.
• Evaluated using three test scenarios: undercrowding, fragmentation, and performance vs efficiency. These can be found in the Test Suite Folder.

Future development will focus on:

• Broader test scenarios and additional metrics (e.g. latency, throughput).
• Support for metric-aware schedulers.
• Scalability evaluation with larger simulated clusters.
• Integration with other orchestration frameworks beyond Kubernetes.

Structure

• src/main/java/org/example - Main folder for CloudSim simulations and the Live_Kubernetes_Broker_EX custom class that implements communication to the middleware.
• k8s-cloudsim-adapter - The middleware/adapter that faclitates communications between CloudSim and Kubernetes.
• second-scheduler - Docker files used to spin-up an instance of the Kubernetes Default Scheduler using a Most Allocated behaviour, which performs basic bin-packing (instead of the default Least Allocated, which puts new pods onto the least busy node).

How to run

You'll need Go, Docker Desktop (for running Container Orchestration Clusters), KWOK and Java JDK21 installed.

You should also clone CloudSim 7.0.1 on your local machine and compile it for use using the mvn clean install -DskipTests command within the CloudSim 7.0.1 repository.

1. Start up Docker Desktop .
2. From the CLI, prepare the KWOK cluster using kwokctl create cluster then kubectl cluster-info --context kwok-kwok.
3. Within the k8s-cloudsim-adapter folder, run go run main.go to start the middleware/adapter.
4. Build and Run any of the tests within src/main/java/org/example/testSuite.

The test should successfully run, with a list of the outcomes of all Cloudlets and some basic metrics being displayed at the end.

Figures

Ideal Design

This diagram showcases the ideal design that this repository aims to follow:

Proof-of-Concept Prototype Implementation

This diagram showcases the implementation design of the Proof-of-Concept Prototype: