Comparative Analysis of Container Runtimes in Kubernetes: Performance Evaluation of Containerd and Cri-O

Abstract

: Container runtimes serve as the foundational layer responsible for the execution and lifecycle management of containers within Kubernetes clusters. While Docker was historically the default runtime, the introduction of the Container Runtime Interface (CRI) has enabled alternative runtimes such as containerd and CRI-O to become first-class citizens in Kubernetes environments. This paper presents a comparative performance analysis of containerd and CRI-O, the two most widely adopted CRI-compliant runtimes, across several critical operational dimensions. The experimental evaluation encompasses container lifecycle operations including creation, start, stop, and deletion times, image pull performance under varying cache conditions, CPU and memory resource utilization during both idle and load scenarios, and pod startup latency in multi-node cluster configurations. The test environment consists of a Kubernetes v1.34 cluster deployed on three identical bare-metal nodes running Ubuntu 26.04 LTS. Results indicate that CRI-O demonstrates marginally faster container creation times due to its lightweight design optimized specifically for Kubernetes, while containerd exhibits superior image caching performance and broader ecosystem compatibility. Both runtimes show comparable memory footprints under sustained workloads. The findings provide practical guidance for infrastructure engineers selecting container runtimes based on specific performance requirements and operational constraints.