Understanding VKS Cluster Deployment Phases in VMware Cloud Foundation 9

Modern private cloud platforms are evolving rapidly, and Kubernetes has become a core requirement for running modern applications. With VMware Cloud Foundation (VCF) and VMware vSphere Kubernetes Service (VKS), deploying Kubernetes clusters is no longer just about creating virtual machines. The complete deployment workflow is highly automated and driven through multiple orchestration phases.

The deployment architecture shown in the image explains how a VKS cluster is created step-by-step, starting from topology generation all the way to worker node availability. Understanding these phases is very important for administrators because it helps in troubleshooting deployment issues, validating infrastructure readiness, and understanding how Kubernetes components interact with vSphere infrastructure.

VKS Cluster Deployment Overview

The deployment workflow is divided into four major phases:

1. Phase 1 – Topology Custom Resource Generation
2. Phase 2 – Infrastructure Provisioning
3. Phase 3 – Control Plane Deployment
• Phase 3a – Control Plane Bootstrap
• Phase 3b – Control Plane VM Provisioning
• Phase 3c – Node Bootstrap
4. Phase 4 – Worker Provisioning

Each phase performs a dedicated function in preparing and deploying the Kubernetes cluster.

Phase 1 – Topology Custom Resource Generation

This is the starting point of the entire deployment workflow.

In this phase, Kubernetes custom resources are generated to define the cluster topology and desired state. These resources are consumed later by Cluster API (CAPI) and vSphere infrastructure providers.

The major components involved are:

• Cluster
• Machine Deployment
• Machine Set
• Kubeadm Control Plane
• vSphere Cluster

Cluster Object

The Cluster object acts as the primary Kubernetes resource representing the Kubernetes cluster being deployed.

It defines:

• Cluster identity
• Networking configuration
• Kubernetes version
• Infrastructure references
• Control plane references

This object becomes the central orchestration point for all subsequent deployment tasks.

Machine Deployment

The Machine Deployment resource defines the desired worker node deployment configuration.

It controls:

• Number of worker nodes
• Worker node scaling
• Worker node upgrade strategy
• Rolling update behaviours

This works similarly to a Kubernetes Deployment object but is used for virtual machine lifecycle management.

Machine Set

The Machine Set resource is automatically generated from the Machine Deployment.

Responsibilities include:

• Creating worker node machines
• Maintaining desired node count
• Replacing failed worker nodes
• Ensuring node consistency

The Machine Set continuously monitors worker node availability.

Kubeadm Control Plane

The Kubeadm Control Plane (KCP) object defines the Kubernetes control plane configuration.

It includes:

• API server configuration
• etcd deployment settings
• Control plane node count
• Bootstrap specifications
• Kubernetes initialization parameters

KCP is responsible for ensuring the Kubernetes control plane remains healthy and highly available.

vSphere Cluster

The vSphere Cluster object maps Kubernetes cluster deployment requirements to the underlying vSphere infrastructure.

It provides:

• Datacenter references
• Datastore selection
• Cluster placement policies
• Network references
• Resource pool configuration

This creates the bridge between Kubernetes orchestration and vSphere infrastructure resources.

Phase 2 – Infrastructure Provisioning

Once the cluster topology is defined, infrastructure provisioning begins.

This phase prepares the required networking and VM infrastructure services before Kubernetes nodes are deployed.

Key components:

• SubnetSet
• VMService
• Infra Ready State

SubnetSet

The SubnetSet resource allocates networking resources required by Kubernetes nodes.

This includes:

• IP allocation
• Network attachment
• Pod network preparation
• Service network preparation

Subnet readiness is extremely important because Kubernetes nodes cannot initialize without proper networking.

VMService

The VMService provides virtual machine lifecycle services for Kubernetes nodes.

Responsibilities include:

• VM creation
• VM power operations
• Resource allocation
• Storage attachment
• VM metadata injection

VMService integrates directly with the Supervisor environment and vSphere infrastructure.

Infra Ready State

After networking and infrastructure services are successfully configured, the deployment reaches the Infra Ready state.

This indicates:

• Networking is operational
• Infrastructure services are reachable
• VM provisioning services are functional
• Deployment prerequisites are satisfied

Only after this validation does the deployment proceed to control plane provisioning.

Phase 3 – Control Plane Deployment

This is one of the most critical stages in VKS cluster deployment.

The Kubernetes control plane is responsible for cluster orchestration, API management, scheduling, and overall cluster health.

Phase 3 is divided into three sub-phases:

• Phase 3a – Control Plane Bootstrap
• Phase 3b – Control Plane VM Provisioning
• Phase 3c – Node Bootstrap

Phase 3a – Control Plane Bootstrap

This phase initializes the Kubernetes control plane configuration.

Key components:

• kubeadmConfig
• Machine CP
• Secret
• SubnetPort

kubeadmConfig

The kubeadmConfig resource contains bootstrap instructions used to initialize Kubernetes.

It defines:

• Kubernetes version
• Cluster initialization commands
• Certificates
• API server settings
• kubelet configuration

This configuration is later injected into the control plane VM.

Machine CP

The Machine CP object represents the control plane machine definition.

It defines:

• VM sizing
• Placement policies
• Bootstrap references
• Infrastructure references

This object acts as the orchestration layer for control plane VM creation.

Secret

The Secret resource stores sensitive deployment data.

Examples include:

• Kubernetes certificates
• Authentication tokens
• kubeconfig files
• Encryption data

Secrets are automatically consumed during bootstrap operations.

SubnetPort

The SubnetPort resource assigns networking interfaces and IP addresses to the control plane node.

This ensures:

• Control plane VM connectivity
• API server reachability
• Cluster communication

Phase 3b – Control Plane VM Provisioning

After bootstrap configuration is ready, the actual control plane VM is deployed.

Main components:

• vSphereMachine
• VirtualMachine

vSphereMachine

The vSphereMachine object defines the infrastructure-specific VM configuration.

It contains:

• VM template references
• Datastore selection
• CPU and memory allocation
• Network attachment
• Storage policies

This object interacts directly with vSphere APIs.

Virtual Machine

The Virtual Machine object represents the actual VM deployed in vSphere.

Once powered on:

• kubeadm bootstrap begins
• Kubernetes binaries initialize
• etcd starts
• API server comes online

At this stage, the Kubernetes control plane starts becoming operational.

Phase 3c – Node Bootstrap

This phase completes Kubernetes initialization.

The major operation here is:

CP Init

Control Plane Initialization performs:

• etcd cluster initialization
• Kubernetes API startup
• Controller Manager startup
• Scheduler startup
• Certificate generation
• Cluster token creation

Once completed:

• Kubernetes API becomes reachable
• Cluster management becomes available
• Worker node provisioning can begin

This is effectively the point where the Kubernetes cluster becomes alive.

 

Phase 4 – Worker Provisioning

After the control plane is operational, worker nodes are deployed.

Key components include:

• KubeadminConfig
• Machine Worker
• vSphereMachine
• VirtualMachine
• SubnetPort
• Available State

Machine Worker

The Machine Worker object defines worker node specifications.

It controls:

• Worker node sizing
• Scaling policies
• Bootstrap references
• Infrastructure references

Worker Node Bootstrap

Worker nodes receive bootstrap configuration from the control plane using kubeadm join operations.

This process includes:

• Fetching cluster certificates
• Registering with API server
• Installing kubelet
• Joining Kubernetes cluster

vSphereMachine and VirtualMachine

Just like control plane deployment, worker nodes are provisioned as virtual machines in vSphere.

These VMs are:

• Attached to Kubernetes networking
• Configured using bootstrap metadata
• Registered into the Kubernetes cluster

Available State

Once worker nodes successfully join the cluster, the deployment reaches the Available state.

This confirms:

• Control plane is healthy
• Worker nodes are operational
• Kubernetes services are functional
• Cluster is ready for workloads

Understanding the Complete Workflow

The complete deployment sequence can be summarized as:

1. Cluster topology definitions are generated
2. Infrastructure resources are prepared
3. Control plane configuration is initialized
4. Control plane VMs are deployed
5. Kubernetes API becomes operational
6. Worker nodes are provisioned
7. Worker nodes join the cluster
8. Cluster reaches available state

Why These Deployment Phases Matter

Understanding these phases is extremely useful for:

Troubleshooting

Administrators can identify exactly where deployment failures occur:

• Topology generation issues
• Infrastructure readiness problems
• VM provisioning failures
• Bootstrap failures
• Node join issues

Operational Visibility

Each phase provides visibility into:

• Infrastructure readiness
• Cluster initialization
• Networking dependencies
• VM lifecycle state

Better Design Planning

Understanding the workflow helps architects design:

• Scalable Kubernetes environments
• Reliable infrastructure layouts
• High availability configurations
• Efficient network planning

The VKS cluster deployment workflow inside VMware Cloud Foundation is designed with a layered and highly automated architecture. Instead of manually deploying Kubernetes components, VKS orchestrates infrastructure provisioning, control plane initialization, networking, VM deployment, and worker node onboarding through a structured deployment pipeline.

Each phase in the deployment process has a very specific responsibility, and together they create a reliable, scalable, and enterprise-ready Kubernetes platform on top of VMware infrastructure.

For administrators working with VMware Cloud Foundation and VKS, understanding these deployment phases is essential for successful implementation, troubleshooting, and lifecycle management of Kubernetes environments.