Tanzu / K8s

Supervisor cluster vs TKG cluster or both?

We talk about Tanzu, but what are the differences between a supervisor cluster and a TKG cluster?

In VMware’s Kubernetes ecosystem, a Supervisor Cluster and a Tanzu Kubernetes Grid (TKG) Cluster serve different but complementary roles. Here’s an overview of each and the key differences between them:

VMware Supervisor Cluster

  • Definition:

A Supervisor Cluster is a Kubernetes cluster that runs directly on vSphere using ESXi as the worker nodes.

  • It integrates Kubernetes natively with vSphere through vSphere with Tanzu.

  • Architecture:

Runs natively on ESXi, with each ESXi host serving as a Kubernetes worker node.

  • Uses vSphere Distributed Switch (vDS) and NSX-T for networking.

  • Incorporates VMware vSphere Pod Service, allowing native Kubernetes Pods to run alongside VMs.

  • Features:

vSphere Pods: Lightweight pods that run directly on ESXi, providing isolation and security similar to VMs.

  • Namespaces: Provide logical and security boundaries for resources within a vSphere environment.

  • Integrated Management: Manage through vCenter, leveraging vSphere roles and permissions.

  • Use Case:

Ideal for Kubernetes workloads that need direct integration with vSphere, particularly for users who want a tightly integrated Kubernetes solution within their existing VMware environment.

Tanzu Kubernetes Grid (TKG) Cluster

  • Definition:

TKG clusters are Kubernetes clusters managed and deployed by VMware Tanzu Kubernetes Grid.

  • Can be deployed on multiple environments: vSphere, public clouds, and at the edge.

  • Architecture:

TKG clusters run on top of the Supervisor Cluster, but also support standalone deployments.

  • Deploys and manages clusters via Cluster API and Kubernetes Operators.

  • Features:

Multi-Cloud Support: Deploys across multiple cloud platforms like AWS, Azure, and vSphere.

  • Cluster API: Automates lifecycle management (creation, scaling, upgrade, and deletion) using Kubernetes-style declarative APIs.

  • Compatible: Works with standard Kubernetes tooling.

  • Use Case:

Best for organizations seeking consistent Kubernetes deployments across hybrid environments (e.g., on-premises and public cloud).

Key Differences

  • Deployment Model:

Supervisor Cluster: Kubernetes control plane runs directly on ESXi hosts.

  • TKG Cluster: Kubernetes clusters deployed on top of the Supervisor Cluster or on other platforms.

  • Network Integration:

Supervisor Cluster: Integrates deeply with NSX-T and vDS for networking and security.

  • TKG Cluster: Uses Calico for networking (NSX-T available for vSphere deployments).

  • Management Interface:

Supervisor Cluster: Managed via vCenter.

  • TKG Cluster: Managed via kubectl, Tanzu CLI, or through vCenter if deployed on a Supervisor Cluster.

  • Workload Types:

Supervisor Cluster: Supports vSphere Pods and Tanzu Kubernetes Clusters.

  • TKG Cluster: Standard Kubernetes clusters for portable workloads.

Summary

  • Supervisor Cluster provides native integration with vSphere and enables Kubernetes workloads to run directly on ESXi.

  • TKG Cluster offers consistent Kubernetes clusters across multiple environments.

TANZU Network choices:

So there is a network difference. This could be important in our design.

What separates the different network options:

Networking Solutions in TKG Clusters

  • Calico:

Default Network Provider: In most TKG clusters, Calico is used as the default Container Network Interface (CNI).

  • Features:

Network Policy: Implements Kubernetes NetworkPolicy for fine-grained traffic control.

  • IP Address Management: Manages pod IP addresses dynamically.

  • Overlay Networking: Uses VXLAN or IP-in-IP encapsulation.

  • Antrea:

Alternative Network Provider: In certain TKG clusters, Antrea is available as an alternative CNI.

  • Features:

Open vSwitch (OVS) based networking.

  • Implements Kubernetes NetworkPolicy.

  • NSX-T Integration:

Available for vSphere Deployments:

When TKG clusters are deployed on vSphere with Tanzu (within Supervisor Clusters), NSX-T can be used as the network provider.

  • Features:

Networking and Security Policies: Provides centralized network security policies via NSX-T.

  • Load Balancer: Offers built-in load balancing.

  • Networking: Supports Tier-0 and Tier-1 routing.

Choosing a Networking Solution

  • Calico:

  • Best suited for environments needing a simple and effective CNI solution.

  • Supports a broad range of TKG deployments.

  • Antrea:

  • Suitable for users looking for an OVS-based solution.

  • Provides efficient networking in TKG clusters.

  • NSX-T:

  • Ideal for environments requiring enterprise-grade networking and security.

  • Deep integration with vSphere and enhanced capabilities.

Clarified Overview

  • Supervisor Cluster (NSX-T or vDS):

NSX-T and vDS are used to provide networking.

  • Supervisor Cluster networks the TKG clusters deployed on top of it.

  • TKG Cluster:

Default CNI: Uses Calico or Antrea by default.

  • NSX-T Integration: Available only for TKG clusters on vSphere.

Summary of Changes

  • Clarification:

NSX-T is not directly available in standalone TKG deployments but requires vSphere Supervisor Clusters.

So why would we have several TKG clusters in a single supervisor cluster?

1. Multi-Tenancy

  • Isolated Environments: Each TKG cluster can be allocated to different teams, departments, or tenants, ensuring that their resources, configurations, and security policies are isolated.

  • Access Control: Kubernetes RBAC can be applied independently within each TKG cluster, simplifying access management.

2. Workload Segmentation

  • Application Isolation: Different applications or microservices can be deployed in separate TKG clusters to minimize resource competition and security risks.

  • Environment Segregation:

Dev/Test/Prod Environments: Keep development, testing, and production workloads separate to avoid cross-environment issues.

  • Compliance: Ensure compliance by separating applications that require different security policies or standards.

3. Resource Management

  • Scalability:

Allows better resource allocation as each TKG cluster can scale independently.

  • Enables efficient use of cluster resources based on workload needs.

  • Resource Quotas:

Each TKG cluster can be configured with quotas for CPU, memory, storage, etc.

  • Prevents one team or tenant from monopolizing resources.

4. Application Modernization

  • Legacy and Modern Applications:

Legacy applications requiring more control can be hosted in dedicated TKG clusters.

  • Modern, cloud-native applications can be placed in separate clusters with different networking or security requirements.

5. Networking Customization

  • Network Policies:

Different clusters can implement network policies using Calico or Antrea tailored to their specific requirements.

  • NSX-T Integration:

NSX-T policies can provide centralized networking and security policies for each TKG cluster.

6. Disaster Recovery and High Availability

  • Fault Isolation:

Multiple TKG clusters within the Supervisor Cluster minimize the impact of a single cluster failure.

  • Backup and Restore:

Backup strategies can be specific to individual TKG clusters.

7. Lifecycle Management

  • Rolling Updates:

Simplifies rolling updates since each TKG cluster can be updated independently.

  • Cluster API (CAPI):

Cluster API facilitates efficient lifecycle management of multiple TKG clusters.

Summary

Deploying multiple TKG clusters within a single Supervisor Cluster provides flexibility, isolation, resource management, and scalability. Organizations can structure their Kubernetes environments according to business needs and application requirements while maintaining security and operational efficiency.