Kubernetes Multi-Clusters:

Containerized deployments offer more scalability and availability improvements over traditional deployments. Even with these improvements, complex applications can quickly overwhelm containerized environments without proper management. Kubernetes helps organizations to:

• Effectively orchestrate containerized environments
• Efficiently manage the underlying resources and user demands

However, there are situations where a single Kubernetes cluster is unable to handle the application load or properly distribute the application to end-users. In such instances, multi-cluster Kubernetes solutions are ideal for distributing the work across multiple clusters.

What is a Kubernetes multi-cluster?

Kubernetes multi-cluster is an environment with multiple Kubernetes clusters. They can be configured in several ways:

• Within a single physical host
• With different multiple hosts in the same data center
• In different regions within a single cloud provider
• Utilizing multiple cloud providers and distributed across multiple regions to provide a truly global multi-cluster environment

Kubernetes multi-cluster architecture

When it comes to multi-cluster architecture, there are two considerations:

• The Kubernetes multi-cluster configuration
• The application architecture

There are primarily two methods to handle a multi-cluster Kubernetes environment:

• The Kubernetes-centric federated method
• The network-centric method

A Kubernetes-centric method uses tools like kubefed to manage multiple Kubernetes clusters from a centralized location (federated clusters). Other tools like Shipperand Admiralty can facilitate:

• Rollout strategies
• Multi-cluster orchestration
• Workload distribution

The network-centric method aims to provide a robust network to facilitate communication between different clusters. The clusters act as separate entities, yet applications can communicate with each other using a network. The network approach is based on mesh networking principles and has adapted service mesh concepts to the infrastructure. An example of this approach is:

• Linkerd service mirroring

Multi-clusters offer multi benefits

Kubernetes multi-clusters is an extensive field composed of multiple implementations and integration methods dictating multi-cluster deployments.

With all the advantages it offers for large-scale applications, it is paramount that you select the appropriate architecture for your multi-cluster environment and tool stack to manage the Kubernetes multi-cluster centrally.