What methods can be used to ensure external connectivity to an application deployed in Kubernetes?

In Kubernetes, the following methods are commonly used to provide external access to an application:

1. Service of type LoadBalancer — automatically creates an external load balancer (if supported by the cloud provider), which directs traffic to the pods.

2. NodePort — opens a fixed port on all cluster nodes, through which the application can be accessed externally.

3. Ingress — an object that manages external access to services, usually via HTTP/HTTPS, with the ability to configure routing rules, SSL, etc.

4. External IP — assigning an external IP address to a service (if the infrastructure supports it).

Example of using Ingress:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
spec:
  rules:
  - host: example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: my-service
            port:
              number: 80

Thus, the choice of method depends on the infrastructure and access requirements.