0008

and DNS are utilized for service discovery, whereas direct container references are used for seed nodes in the Docker Compose setup. Question) How does the Cassandra service know which Pods are part of the service? e A Service in Kubernetes selects the Pods that are part of the service using labels and selectors. Using a selector, the Cassandra Service in the specified YAML configuration selects Pods with specific labels. e Seclector of Services: o The selection field in the Cassandra Service definition: This selector instructs the Service to choose all Pods with the label app and the value cassandra. e Pod Labels: o Set the app label for the Pods in the Cassandra StatefulSet template to cassandra: This labeling ensures that the app: cassandra label appears on all Pods created by the StatefulSet. e (Cassandra Service finds all Pods in the cluster that contain the label app: cassandra when it is created. These Pods are then included in the Cassandra Service. e Routing Traffic: Once the Service determines which Pods are a part of it, it creates the network routing rules required to distribute traffic to these selected Pods based on the Service's type and port configuration. The Service in this is a "headless" Service (ClusterIP: None), which indicates that it does not load balance traffic and instead permits direct contact with individual Pods. It's commonly used for StatefulSets, such as the one in the configuration.