Guide to Building a Custom Kubernetes Scheduler

Sun, 24 Aug 2025 17:30:00 +0000

This guide will walk you through creating a custom scheduler plugin that influences where pods are placed based on custom logic. We will build a simple “Network-Aware” plugin that prefers to schedule pods on nodes with a specific network label.

What We Will Build:

A Filter plugin: It will only allow pods that request high-speed networking to be scheduled on nodes that are labeled as network-topology=high-speed.
A Score plugin: It will give a higher score to nodes with the high-speed label, making them more desirable.
We will then package this plugin into a new scheduler binary, containerize it, and deploy it to a local Kubernetes cluster.

Part 1: Understanding the Foundations - The Scheduling Framework

Before writing any code, it’s crucial to understand the “why” and “how”.

Setting Up a Kubernetes Cluster with Kubeadm and CRI-O

Tue, 25 Mar 2025 16:40:16 +0000

Prerequisites

Before setting up a Kubernetes cluster using Kubeadm and CRI-O, ensure that you meet the following requirements:

Hardware Requirements

At least 2 GB of RAM per node (4 GB recommended for the master node)
At least 2 CPUs per node
20 GB of free disk space
A stable internet connection
All nodes should be able to communicate with each other

Software Requirements

A supported Linux distribution (Ubuntu 20.04+ or Debian 10+ recommended)
User access with sudo privileges
Basic understanding of Linux command-line interface (CLI)
Knowledge of networking concepts

Step 1: Configure Kernel Parameters

Kubernetes requires some kernel parameters to be set to allow IPtables to see bridged traffic.