vcluster

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vcluster - Virtual Clusters For Kubernetes

• Lightweight & Low-Overhead - Based on k3s, bundled in a single pod and with super-low resource consumption
• No Performance Degradation - Pod are scheduled in the underlying host cluster, so they get no performance hit at all while running
• Reduced Overhead On Host Cluster - Split up large multi-tenant clusters into smaller vcluster to reduce complexity and increase scalability
• Flexible & Easy Provisioning - Create via vcluster CLI, helm, kubectl, Argo any of your favorite tools (it is basically just a StatefulSet)
• No Admin Privileges Required - If you can deploy a web app to a Kubernetes namespace, you will be able to deploy a vcluster as well
• Single Namespace Encapsulation - Every vcluster and all of its workloads are inside a single namespace of the underlying host cluster
• Easy Cleanup - Delete the host namespace and the vcluster plus all of its workloads will be gone immediately

Learn more on www.vcluster.com.

Architecture

Learn more in the documentation.

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Quick Start

To learn more about vcluster, open the full getting started guide.

1. Download vcluster CLI

Use one of the following commands to download the vcluster CLI binary from GitHub:

Mac (Intel/AMD)

curl -s -L "https://github.com/loft-sh/vcluster/releases/latest" | sed -nE 's!.*"([^"]*vcluster-darwin-amd64)".*!https://github.com\1!p' | xargs -n 1 curl -L -o vcluster && chmod +x vcluster;
sudo mv vcluster /usr/local/bin;

Mac (Silicon/ARM)

curl -s -L "https://github.com/loft-sh/vcluster/releases/latest" | sed -nE 's!.*"([^"]*vcluster-darwin-arm64)".*!https://github.com\1!p' | xargs -n 1 curl -L -o vcluster && chmod +x vcluster;
sudo mv vcluster /usr/local/bin;

Linux (AMD)

curl -s -L "https://github.com/loft-sh/vcluster/releases/latest" | sed -nE 's!.*"([^"]*vcluster-linux-amd64)".*!https://github.com\1!p' | xargs -n 1 curl -L -o vcluster && chmod +x vcluster;
sudo mv vcluster /usr/local/bin;

Linux (ARM)

curl -s -L "https://github.com/loft-sh/vcluster/releases/latest" | sed -nE 's!.*"([^"]*vcluster-linux-arm64)".*!https://github.com\1!p' | xargs -n 1 curl -L -o vcluster && chmod +x vcluster;
sudo mv vcluster /usr/local/bin;

Windows (Powershell)

md -Force "$Env:APPDATA\vcluster"; [System.Net.ServicePointManager]::SecurityProtocol = [System.Net.SecurityProtocolType]'Tls,Tls11,Tls12';
Invoke-WebRequest -UseBasicParsing ((Invoke-WebRequest -URI "https://github.com/loft-sh/vcluster/releases/latest" -UseBasicParsing).Content -replace "(?ms).*`"([^`"]*vcluster-windows-amd64.exe)`".*","https://github.com/`$1") -o $Env:APPDATA\vcluster\vcluster.exe;
$env:Path += ";" + $Env:APPDATA + "\vcluster";
[Environment]::SetEnvironmentVariable("Path", $env:Path, [System.EnvironmentVariableTarget]::User);

If you get the error that Windows cannot find vcluster after installing it, you will need to restart your computer, so that the changes to the PATH variable will be applied.

Alternatively, you can download the binary for your platform from the GitHub Releases page and add this binary to your PATH.

2. Create a vcluster

vcluster create vcluster-1 -n host-namespace-1

Alternative A: Helm

Create file vcluster.yaml:

vcluster:
  image: rancher/k3s:v1.19.5-k3s2    
  extraArgs:
    - --service-cidr=10.96.0.0/12    
  baseArgs:
    - server
    - --write-kubeconfig=/k3s-config/kube-config.yaml
    - --data-dir=/data
    - --no-deploy=traefik,servicelb,metrics-server,local-storage
    - --disable-network-policy
    - --disable-agent
    - --disable-scheduler
    - --disable-cloud-controller
    - --flannel-backend=none
    - --kube-controller-manager-arg=controllers=*,-nodeipam,-nodelifecycle,-persistentvolume-binder,-attachdetach,-persistentvolume-expander,-cloud-node-lifecycle
storage:
  size: 5Gi

Deploy vcluster via helm:

helm upgrade --install vcluster-1 vcluster \
  --values vcluster.yaml \
  --repo https://charts.loft.sh \
  --namespace vcluster-1 \
  --repository-config=''

Alternative B: kubectl

Create file vcluster.yaml:

apiVersion: v1
kind: ServiceAccount
metadata:
  name: vcluster-1
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: vcluster-1
rules:
  - apiGroups: [""]
    resources: ["configmaps", "secrets", "services", "services/proxy", "pods", "pods/proxy", "pods/attach", "pods/portforward", "pods/exec", "pods/log", "events", "endpoints", "persistentvolumeclaims"]
    verbs: ["*"]
  - apiGroups: ["networking.k8s.io"]
    resources: ["ingresses"]
    verbs: ["*"]
  - apiGroups: [""]
    resources: ["namespaces"]
    verbs: ["get", "list", "watch"]
  - apiGroups: ["apps"]
    resources: ["statefulsets"]
    verbs: ["get", "list", "watch"]
---
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: vcluster-1
subjects:
  - kind: ServiceAccount
    name: vcluster-1
roleRef:
  kind: Role
  name: vcluster-1
  apiGroup: rbac.authorization.k8s.io
---
apiVersion: v1
kind: Service
metadata:
  name: vcluster-1
spec:
  type: ClusterIP
  ports:
    - name: https
      port: 443
      targetPort: 8443
      protocol: TCP
  selector:
    app: vcluster-1
---
apiVersion: v1
kind: Service
metadata:
  name: vcluster-1-headless
spec:
  ports:
    - name: https
      port: 443
      targetPort: 8443
      protocol: TCP
  clusterIP: None
  selector:
    app: vcluster-1
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: vcluster-1
  labels:
    app: vcluster-1
spec:
  serviceName: vcluster-1-headless
  replicas: 1
  selector:
    matchLabels:
      app: vcluster-1
  template:
    metadata:
      labels:
        app: vcluster-1
    spec:
      terminationGracePeriodSeconds: 10
      serviceAccountName: vcluster-1
      containers:
      - image: rancher/k3s:v1.19.5-k3s2
        name: virtual-cluster
        command:
          - "/bin/k3s"
        args:
          - "server"
          - "--write-kubeconfig=/k3s-config/kube-config.yaml"
          - "--data-dir=/data"
          - "--disable=traefik,servicelb,metrics-server,local-storage"
          - "--disable-network-policy"
          - "--disable-agent"
          - "--disable-scheduler"
          - "--disable-cloud-controller"
          - "--flannel-backend=none"
          - "--kube-controller-manager-arg=controllers=*,-nodeipam,-nodelifecycle,-persistentvolume-binder,-attachdetach,-persistentvolume-expander,-cloud-node-lifecycle"  
          - "--service-cidr=10.96.0.0/12"  
        volumeMounts:
          - mountPath: /data
            name: data
      - name: syncer
        image: "loftsh/virtual-cluster:0.0.27"
        args:
          - --service-name=vcluster-1
          - --suffix=vcluster-1
          - --owning-statefulset=vcluster-1
          - --out-kube-config-secret=vcluster-1
        volumeMounts:
          - mountPath: /data
            name: data
  volumeClaimTemplates:
    - metadata:
        name: data
      spec:
        accessModes: [ "ReadWriteOnce" ]
        resources:
          requests:
            storage: 5Gi

Create vcluster using kubectl:

kubectl apply -f vcluster.yaml

Alternative C: Other

Get the Helm chart or Kubernetes manifest and use any tool you like for the deployment of a vcluster, e.g. Argo, Flux etc.

3. Use the vcluster

# Start port-forwarding to the vcluster service + set kube-config file
vcluster connect vcluster-1 -n host-namespace-1
export KUBECONFIG=./kubeconfig.yaml

# OR: Start port-forwarding and add kube-context to current kube-config file
vcluster connect vcluster-1 -n host-namespace-1 --update-current

# Run any kubectl, helm, etc. command in your vcluster
kubectl get namespace
kubectl get pods -n kube-system
kubectl create namespace demo-nginx
kubectl create deployment nginx-deployment -n demo-nginx --image=nginx
kubectl get pods -n demo-nginx

4. Cleanup

vcluster delete vcluster-1 -n host-namespace-1

Alternatively, you could also delete the host-namespace using kubectl.

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This project is open-source and licensed under Apache 2.0, so you can use it in any private or commercial projects.