Kubernetes – Cluster IP vs Node-Port

The ClusterIP provides a load-balanced IP address. One or more pods that match a label selector can forward traffic to the IP address. The ClusterIP service must define one or more ports to listen on with target ports to forward TCP/UDP traffic to containers.

Cluster IP:

• This is the default service type that exposes the service on a cluster-internal IP by making the service only reachable within the cluster.
• A Cluster service is the default Kubernetes service. It gives you a service inside your cluster that other apps inside your cluster can access.
• There is no external process.

When to use Cluster IP?

• There are a few scenarios where you would use the Kubernetes proxy to access your services.
• debugging your services, or connecting to them directly from your laptop for some reason
• Allowing internal traffic, displaying internal dashboards, etc.

Node port:

This exposes the service on each Node’s IP at a static port. Since a ClusterIP service, to which the NodePort service will route, is automatically created. We can contact the NodePort service outside the cluster.

• A Nodeport service is the most primitive way to get external traffic directly to your service.
• NodePort, as the same implies, opens a specific port on all the Nodes (the VMs), and any traffic that is sent to this port is forwarded to the service.

When to use Node Port?

• There are many downsides to this method
• You can only have one service per port
• You can only use ports 30,000-32,767
• If your Node/VM IP address change, you need to deal with that
• For these reasons, I don’t recommend using this method in production to directly expose your service. If you are running a service that doesn’t have to be always available, or you are very cost-sensitive, this method will work for you. A good example of such an application is a demo app or something temporary.

My Personal Notes arrow_drop_up

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