Efficient Container Image Distribution for Multi-Tenant Kubernetes Clusters

The distributed Kubernetes environment utilizes container images to run designated workloads. Image registries, which store these container images, can be located either inside or outside the Kubernetes cluster, depending on the product and application requirements. Container image sizes can vary according to the type and scale of workload. Consequently, the application startup time depends on the duration of the image download phase. If the image registry is hosted on a low-bandwidth link outside the cluster, this can negatively impact the application's startup time. Prolonged download times may saturate the internet link, potentially violating SLA agreements, and causing issues in production environments. Previous approaches have primarily focused on building a P2P network across Kubernetes nodes to facilitate the local distribution of images. However, in multi-tenant environments or when disk space is constrained, this method becomes impractical. In this paper, we introduce a novel method that distributes container images only to the nodes when required, leveraging the local high-bandwidth network. This approach reduces disk space utilization and decreases the application's startup time. Under resource-intensive conditions, the proposed method achieved a reduction in image download time of approximately 50 %.