Kubernetes Dashboard Port: A Comprehensive Guide

Kubernetes Dashboard is a web-based user interface for managing and monitoring Kubernetes clusters. It provides a graphical way to interact with various Kubernetes resources such as pods, deployments, and services. One of the crucial aspects of setting up and accessing the Kubernetes Dashboard is understanding the concept of ports. The port determines how external users or systems can reach the dashboard, and proper configuration is essential for security and functionality. In this blog post, we will explore the core concepts, typical usage examples, common practices, and best practices related to the Kubernetes Dashboard port.

Table of Contents

  1. Core Concepts
    • What is a Port in Kubernetes?
    • Role of Ports in Kubernetes Dashboard
  2. Typical Usage Example
    • Deploying Kubernetes Dashboard
    • Exposing the Dashboard with a Specific Port
  3. Common Practices
    • Using NodePort
    • Using LoadBalancer
    • Using Ingress
  4. Best Practices
    • Security Considerations
    • Port Allocation Strategy
  5. Conclusion
  6. References

Core Concepts

What is a Port in Kubernetes?

In Kubernetes, a port is a communication endpoint within a network. It is used to distinguish different services running on the same IP address. Ports are numbered from 0 to 65535, and different ranges are reserved for specific purposes. For example, ports below 1024 are typically reserved for system services, while ports above 1024 are available for user applications.

Role of Ports in Kubernetes Dashboard

The Kubernetes Dashboard is a web application that needs to be accessible from outside the cluster. The port determines how clients can connect to the dashboard. By default, the Kubernetes Dashboard runs on a specific port inside the cluster, but to make it accessible externally, you need to expose it using a Kubernetes service and specify the appropriate port.

Typical Usage Example

Deploying Kubernetes Dashboard

First, you need to deploy the Kubernetes Dashboard to your cluster. You can use the official manifest provided by the Kubernetes Dashboard project.

kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.5.1/aio/deploy/recommended.yaml

Exposing the Dashboard with a Specific Port

To expose the dashboard, you can create a service. Here is an example of a NodePort service:

apiVersion: v1
kind: Service
metadata:
  name: kubernetes-dashboard-nodeport
  namespace: kubernetes-dashboard
spec:
  type: NodePort
  ports:
    - port: 443
      targetPort: 8443
      nodePort: 30443
  selector:
    k8s-app: kubernetes-dashboard

Apply the service using kubectl apply -f <filename>.yaml. Now, you can access the dashboard at https://<node-ip>:30443.

Common Practices

Using NodePort

NodePort is a simple way to expose the Kubernetes Dashboard. It opens a port on each node in the cluster, and traffic sent to this port is forwarded to the dashboard. The advantage of NodePort is its simplicity, but it has limitations in terms of security and scalability.

Using LoadBalancer

If you are running your Kubernetes cluster on a cloud provider that supports load balancers, you can use the LoadBalancer service type. The cloud provider will create an external load balancer and assign a public IP address to it. Traffic sent to this IP address is then forwarded to the dashboard.

apiVersion: v1
kind: Service
metadata:
  name: kubernetes-dashboard-loadbalancer
  namespace: kubernetes-dashboard
spec:
  type: LoadBalancer
  ports:
    - port: 443
      targetPort: 8443
  selector:
    k8s-app: kubernetes-dashboard

Using Ingress

Ingress is a more advanced way to expose the Kubernetes Dashboard. It allows you to manage external access to the dashboard using rules defined in an Ingress resource. You can configure features such as SSL termination, path-based routing, and rate limiting.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: kubernetes-dashboard-ingress
  namespace: kubernetes-dashboard
spec:
  rules:
    - host: dashboard.example.com
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: kubernetes-dashboard
                port:
                  number: 8443

Best Practices

Security Considerations

  • Use HTTPS: Always use HTTPS to encrypt the communication between the client and the dashboard. You can configure SSL/TLS certificates for the dashboard service.
  • RBAC: Implement Role-Based Access Control (RBAC) to restrict access to the dashboard. Only authorized users should be able to access it.
  • Limit External Access: Use firewalls and network policies to limit external access to the dashboard port.

Port Allocation Strategy

  • Avoid Well-Known Ports: Do not use well-known ports (e.g., 80, 443) for the dashboard if possible. This reduces the risk of conflicts with other services.
  • Document Port Usage: Keep a record of the ports used in your cluster to avoid conflicts and ensure proper maintenance.

Conclusion

Understanding the Kubernetes Dashboard port is crucial for deploying and accessing the dashboard securely and effectively. By following the common practices and best practices outlined in this blog post, you can ensure that your Kubernetes Dashboard is accessible to the right users while maintaining a high level of security. Whether you choose to use NodePort, LoadBalancer, or Ingress, each method has its own advantages and considerations.

References