# vCluster — Virtual Kubernetes Clusters Inside Real Clusters

> vCluster creates lightweight virtual Kubernetes clusters that run inside namespaces of a host cluster, giving teams isolated environments without the cost and complexity of separate physical clusters.

## Install

Save in your project root:

# vCluster — Virtual Kubernetes Clusters Inside Real Clusters

## Quick Use
```bash
# Install vCluster CLI
curl -L -o vcluster https://github.com/loft-sh/vcluster/releases/latest/download/vcluster-linux-amd64
chmod +x vcluster && sudo mv vcluster /usr/local/bin/

# Create a virtual cluster
vcluster create my-vcluster --namespace team-a
vcluster connect my-vcluster --namespace team-a
kubectl get namespaces  # inside the virtual cluster
```

## Introduction
vCluster by Loft Labs lets you spin up fully functional Kubernetes clusters inside namespaces of a host cluster. Each virtual cluster has its own API server, control plane, and syncer but shares the underlying worker nodes. This gives development teams, CI pipelines, and multi-tenant platforms the isolation of separate clusters at a fraction of the resource cost.

## What vCluster Does
- Creates virtual Kubernetes clusters with dedicated API servers inside host namespaces
- Syncs resources (pods, services, ingresses) between virtual and host clusters transparently
- Provides full cluster-admin inside virtual clusters without host-level privileges
- Supports any Kubernetes distribution as the virtual control plane (k3s, k0s, vanilla k8s)
- Integrates with Helm, ArgoCD, and standard kubectl workflows

## Architecture Overview
Each vCluster runs a lightweight control plane (by default k3s) and a syncer component inside a single pod in the host namespace. The syncer watches resources created in the virtual cluster and replicates them to the host cluster, rewriting names to avoid conflicts. Pods scheduled in the virtual cluster actually run on host nodes, but they appear namespaced and isolated from the virtual cluster perspective. The host cluster handles all actual scheduling and networking.

## Self-Hosting & Configuration
- Install the vCluster CLI or use the Helm chart for GitOps-driven creation
- Run `vcluster create <name> -n <namespace>` to spin up a virtual cluster in seconds
- Configure resource limits, synced resource types, and distro in `vcluster.yaml`
- Enable isolated mode to restrict virtual cluster workloads from accessing host resources
- Use `vcluster connect` to merge a kubeconfig context for seamless kubectl access

## Key Features
- Spin up a full virtual cluster in under 30 seconds with minimal resource overhead
- Full CRD support — install any operator inside the virtual cluster independently
- Sleep mode automatically scales down idle virtual clusters to zero resources
- Host cluster stays clean — virtual cluster resources are namespaced and garbage-collected on delete
- Platform edition adds SSO, quotas, and self-service virtual cluster provisioning via UI

## Comparison with Similar Tools
- **Namespaces** — basic isolation but no separate API server, CRD conflicts, and no cluster-admin
- **Kind/Minikube** — local-only clusters; vCluster runs inside production infrastructure
- **Cluster API** — provisions real clusters on cloud providers; heavier and slower than vCluster
- **Crossplane** — infrastructure provisioning tool, not Kubernetes multi-tenancy
- **Capsule** — namespace-based multi-tenancy without virtual API servers

## FAQ
**Q: Does vCluster work with any Kubernetes distribution?**
A: Yes. The host can be EKS, GKE, AKS, or any conformant cluster. The virtual control plane defaults to k3s but supports k0s and vanilla Kubernetes.

**Q: Are virtual clusters truly isolated?**
A: Virtual clusters provide API-level isolation. Workloads share host nodes by default, but you can enable isolated mode with network policies and resource quotas for stronger boundaries.

**Q: Can I install CRDs in a virtual cluster?**
A: Yes. Each virtual cluster has its own API server, so CRDs are fully independent and do not conflict with the host or other virtual clusters.

**Q: Is vCluster free?**
A: The open-source CLI and Helm chart are free under Apache 2.0. The commercial Platform edition adds UI, SSO, and governance features.

## Sources
- https://github.com/loft-sh/vcluster
- https://www.vcluster.com/docs/

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Source: https://tokrepo.com/en/workflows/f23363bd-3942-11f1-9bc6-00163e2b0d79
Author: AI Open Source