Hosted Control Planes

A notable evolution and special case in multi-cluster federation architecture is the concept of Hosted Control Planes (HCP), originating from the idea of Kubeception^[1], that is recursively deploying Kubernetes with or in Kubernetes. With HCP the control and data plane components are hosted as tenant workloads in the worker plane of another cluster, a so-called host or seed cluster. Notably, HCP at its core is a Control-Plane-as-a-Service offering. The HCP approach offers:

• Cost Efficiency: Organizations can reduce operational overhead and costs associated with maintaining dedicated cluster infrastructure.
• Faster Provisioning: HCPs enable quicker cluster provisioning times, as the control and data plane can be treated like any other cloud-native component deployment.
• Security Optimizations: With the planes managed separately, HCP enhances security, including strong isolation boundaries between control and work plane.
• Cloud-Native Benefits: Kubernetes is the cloud-native reference system for automating deployment, scaling, and management of containerized software. As Kubernetes itself is (containerized) software, we inherit all cloud-native advantages and benefits by using Kubernetes to deploy, host, and operate Kubernetes.

Hosted Control Planes

Learned Kubernetes skills become portable across all layers of the cloud stack; from the technical infrastructure to the platform and service layers.

Managed Kubernetes Provider

The HCP architecture^[2] plays a crucial role in building Managed Kubernetes-as-a-Service offerings, which form an indispensable platform runtime service. This cloud-native underlay service supports application and service teams with universal on-demand runtimes (Kubernetes offers highly useful abstractions for their business needs). Portability features allow using Kubernetes as a lingua franca across different infrastructure providers. This underlay allows for other platform services to be offered and operated, forming the basis of a distributed Cloud Operating System (COS).

Automated operations and enterprise-readiness at scale are a key factor for Managed Kubernetes-as-a-Service, as depicted by the tip of the iceberg idiom:

Operating K8s

(Source: Gardener documentation)

Project Gardener

is the default Kubernetes-as-a-Service provider of choice in ApeiroRA. It specifically has codified and automated crucial operational features which elevate the otherwise generic HCP architecture to enterprise-readiness level. For example, Gardener automates the management and scaling of its own hosting infrastructure.

Although the Gardener architecture is a variant of the more generic HCP architecture, its specific architecture also provided the blueprint for comprehensive Managed Service Providers (MSP). MSP is a service provisioning system capable of initializing and managing its own hosting or seed infrastructure across available resources in the cloud-edge-continuum, with the goal to offer desired, specialized services.

Gardener Schematics

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1. KubeCeption! A Story of Self-Hosted Kubernetes and Turtles All the Way Down: Inception for Kubernetes. ↩︎

2. Hosting Control Planes can be implemented with or without Kubeception. Any qualified platform can be instrumented to provide the host environment (cf. MKE or Docker). ↩︎