Tell about traffic routing between services in Kubernetes.

In Kubernetes, traffic routing between services is handled using Service objects and DNS. Each Service gets a stable IP and DNS name within the cluster, allowing pods to communicate with each other by service name.

Main mechanisms:

• ClusterIP — an internal IP accessible only within the cluster. Pods access the service via this IP or DNS name.
• DNS — kube-dns or CoreDNS automatically create records for services, e.g., my-service.namespace.svc.cluster.local.
• Endpoints — Service connects traffic to a set of pods through Endpoints.
• Network Policies — allow restricting traffic between pods and services.

Example of communication from one pod to another:

curl http://my-service.namespace.svc.cluster.local:80

Thus, routing within the cluster occurs at the DNS and IP level, with kube-proxy and CNI plugins ensuring network packet delivery.