Cloud native implementations, growing in scale and complexity, are challenging organizations on how to efficiently, reliably manage large-scale resource pools to meet growing demands. Players in the cloud field attempted to scale out single clusters by customizing native Kubernetes components, which complicated single-cluster operations and maintenance, beclouded cluster upgrade paths, let alone many other problems. This is where multi-cluster technologies come into play. They can scale resource pools horizontally without invasively modifying each single cluster, while reducing O&M costs.
The popularity of Karmada is now drawing users' attention to Karmada's scalability and deployment at scale. Therefore, we launched a large-scale test on Karmada to obtain baseline performance metrics for Karmada managing multiple Kubernetes clusters. For multi-cluster systems represented by Karmada, the size of a single cluster is not a limiting factor restricting the scalability. On that account, we referred to the standard configurations of Kubernetes large-scale clusters and real-world implementations, and tested Karmada on managing 100 Kubernetes clusters (each cluster containing 5k nodes and 20k pods) at the same time. Limited by the environment and tooling, this test is not designed for stress testing Karmada, but for using Karmada in typical multi-cluster scenarios in production. The test results show that Karmada can stably support 100 large-scale clusters with 500,000 nodes connected at the same time, running more than 2 million pods.
This article will introduce the metrics used in the test, how to conduct large-scale testing, and how we realize massive connection of nodes and clusters.
Cloud computing is entering a new stage featuring multicloud and distributed clouds. As surveyed by Flexera, a well-known analyst company, more than 93% of enterprises are using services from multiple cloud vendors at the same time. Single Kubernetes clusters, limited by their capacity and fault recovery capabilities, cannot support services to run as distributed as wanted, especially if one's organization wants to go globalization. A hybrid cloud or multi-public cloud architecture helps avoid vendor lock-in or optimize costs. Karmada users are also demanding large-scale node and application management in their multi-cluster deployments.