How can external access to internal services be achieved in Kubernetes?

In Kubernetes, internal services can be accessed in the following ways:

1. Kubernetes assigns a Cluster IP to each Service, which is only accessible within the cluster. This IP address can be used to access the Service, such as accessing it from a Pod within the cluster using the Cluster IP address.
2. NodePort is a method to expose a Service outside the cluster by opening a static port on each node, allowing access to the Service using the node’s IP address and NodePort. For example, if the NodePort is set to 30000, the Service can be accessed using http://:30000.
3. When using a LoadBalancer, setting the LoadBalancer type in the Service automatically creates an external load balancer to route requests to the Service. This requires support from the cloud service provider and typically involves providing additional configurations, such as a public cloud provider’s load balancer.
4. Utilizing Ingress: Ingress is a method of routing HTTP and HTTPS traffic to internal services within a cluster. By creating Ingress resources and configuring appropriate rules, external requests can be directed to internal services. This requires support from an Ingress controller and the configuration of DNS for resolving the domain of the Ingress.

Based on specific needs and the environment, you can choose an appropriate method to access internal services.