🚀 Installing Rancher on an Existing EKS Cluster (Without a Domain) — Step-by-Step Guide

Rancher is a powerful Kubernetes management platform that allows you to centrally manage multiple clusters. In this blog, we’ll walk through how to install Rancher on an existing Amazon EKS cluster, without needing a domain name. This setup is ideal for testing, development, or internal environments.

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🧠 What is Rancher?

Rancher is an open-source container management platform that:

• Provides a beautiful web UI and API for managing K8s clusters

• Supports importing, creating, and managing clusters across cloud providers

• Includes role-based access control (RBAC), monitoring, backup, and more

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🛠️ Prerequisites

• An existing Amazon EKS cluster

• kubectl configured to access the EKS cluster

• helm CLI installed (v3+ recommended)

• AWS CLI configured

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🧱 Step 1: Add the Rancher Helm Chart Repository

Add the latest Rancher Helm chart repo:

helm repo add rancher-latest https://releases.rancher.com/server-charts/latest

Update the local repo cache:

helm repo update

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📦 Step 2: Create the Rancher Namespace

Rancher installs all of its components inside the cattle-system namespace. Create it using:

kubectl create namespace cattle-system

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🔐 Step 3: Install Cert-Manager

Rancher requires cert-manager to issue and manage TLS certificates.

👉 Apply CRDs first (Custom Resource Definitions):

kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.17.0/cert-manager.crds.yaml

👉 Add the Jetstack Helm repo and install cert-manager:

helm repo add jetstack https://charts.jetstack.io
helm repo update

Install cert-manager into its own namespace:

helm install cert-manager jetstack/cert-manager \
  --namespace cert-manager \
  --create-namespace \
  --version v1.17.0

Confirm cert-manager pods are running:

kubectl get pods --namespace cert-manager

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🚀 Step 4: Install Rancher

Install Rancher using the helm install command:

helm install rancher rancher-latest/rancher \
  --namespace cattle-system \
  --set hostname=rancher.my.org \
  --set bootstrapPassword=admin

🔒 Note: Since we are not using a real domain, rancher.my.org is just a placeholder. We’ll access Rancher via LoadBalancer IP.

Wait for the Rancher deployment to roll out:

kubectl -n cattle-system rollout status deploy/rancher

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🌐 Step 5: Expose Rancher via LoadBalancer

Since you don’t have a domain, expose Rancher using a LoadBalancer service:

kubectl expose deployment rancher \
  --name=rancher-lb \
  --port=443 \
  --type=LoadBalancer \
  -n cattle-system

Check the service and get the external IP:

kubectl get svc -n cattle-system

Look for the EXTERNAL-IP of rancher-lb. Once it’s available, open your browser and go to:

https://<external-ip>

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⚠️ Step 6: Handling Self-Signed Certificates

Since no real domain and no public certificate is used, Rancher will generate a self-signed TLS certificate. When you visit https://<external-ip>, you’ll see a browser warning like:

“Your connection is not private” or “Untrusted Certificate”

✅ To Proceed:

• Click on Advanced

• Click Proceed to <external-ip> (unsafe)

This is expected and safe for testing or internal environments. In production, you should use a real domain with a valid SSL cert.

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🔐 Step 7: Login with Bootstrap Password

1. On the Rancher login page, enter username: admin, password: admin (from --set bootstrapPassword=admin)

2. You'll be asked to set a new admin password.

   • Check the box for “Use a randomly generated password”

   • Save it or copy it to a secure location

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🖥️ Step 8: Explore the Rancher UI

Once logged in:

• You’ll see the “local” cluster, which is the EKS cluster where Rancher is installed.

• You can now:

  • Add or import more Kubernetes clusters

  • Deploy workloads

  • Set up monitoring, alerts, backups, RBAC policies, and more

When to Use This Setup?

✅ Ideal for:

• Lab/demo environments

• Internal tooling

• CI/CD testing clusters

• Admin experimentation

🚫 Not recommended for:

• Production workloads

• Multi-user public access

• Long-term external services (without DNS/SSL setup)

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🧵 Conclusion

Installing Rancher on an EKS cluster without a domain is absolutely possible and easy. This guide helps you:

• Install Rancher using Helm

• Set up cert-manager

• Expose Rancher via a LoadBalancer

• Handle self-signed certs safely

• Get started with managing Kubernetes via Rancher UI