CKA Certification Course 2025 - Day 46: Pod Priority, PriorityClass, and Preemption in Kubernetes | CKA Course 2025

Day 46: Pod Priority, PriorityClass, and Preemption in Kubernetes | CKA Course 2025 👉 GitHub Repository: https://github.com/CloudWithVarJosh/CKA-Certification-Course-2025 👉 CKA 2025 Playlist: https://youtube.com/playlist?list=PLmPit9IIdzwRjqD-l_sZBDdPlcSfKqpAt&si=1JNRkoNa75AOJx0o 📚 Welcome to Day 46! In this lecture, we explore one of the most powerful scheduling features in Kubernetes: Pod Priority and Preemption. Not all workloads are created equal—some are business-critical and must take precedence over others, especially during resource contention. You’ll learn how to define and use PriorityClass objects, how the Kubernetes scheduler handles high and low-priority pods, and how preemption ensures resource fairness during cluster pressure. We'll also discuss the role of preemptionPolicy, how system-critical pods are protected with system-level priority classes, and the limitations around user-defined priority values. We wrap the session with a hands-on demo using a KIND cluster to simulate a real-world scenario where high-priority pods evict low-priority ones when resources are tight. 📝 What We’ll Cover: ✅ Why pod priority and preemption are essential in production ✅ Understand PriorityClass, its numeric values, and how to define them ✅ System-reserved priority classes vs user-defined ones ✅ What happens during extreme resource pressure ✅ How preemption helps critical pods get scheduled ✅ Use of preemptionPolicy: Never and when to apply it ✅ Best practices: defining default priority, naming strategies, and avoiding disruption ✅ Demo: Scheduling & Eviction Based on Pod Priority 💡 By the end of this lecture: You’ll know how to define, apply, and troubleshoot pod scheduling using priority classes, when to avoid preemption, and how to safely simulate these behaviors in a Kubernetes cluster. 🔗 Stay Connected: 👉 LinkedIn: https://linkedin.com/in/varun-joshi-2b516752 👉 GitHub: https://github.com/CloudWithVarJosh 💬 Got questions? Drop them in the comments — I reply to every single one. 👍 Like, share, and subscribe to follow the entire CKA 2025 series! ⏰ Timestamps 00:00:00 Introduction 00:00:35 Why Do Pod Priority and Preemption Exist? 00:04:12 Understanding PriorityClass and How It Works 00:08:50 Demo: Scheduling & Eviction Based on Pod Priority 00:27:04 Conclusion and What’s Next 🔖 Hashtags #Kubernetes #CKA #CloudWithVarJosh #CKACourse #CKA2025 #PodPriority #KubernetesScheduler #Preemption #PriorityClass #K8sScheduling #KubernetesDemo #K8sResources #SystemPods #KindCluster #PreemptionPolicy #K8sProduction #ClusterEviction #DevOps #CloudNative #CKAExamPrep #KubernetesBestPractices #CKALabs #K8sResilience #SRE #KubernetesForAdmins