Ace Your C_KYMD_01 SAP Certified Development Associate Exam

• The API server is a component of the Kubernetes control plane that exposes the Kubernetes API. The API server is the front end for the Kubernetes control plane. The main implementation of a Kubernetes API server is kube-apiserver . kube-apiserver is designed to scale horizontally—that is, it scales by deploying more instances. You can run several instances of kube-apiserver and balance traffic between those instances. etcd Consistent and highly-available key value store used as Kubernetes’ backing store for all clusterdata. If your Kubernetes cluster uses etcd as its backing store, make sure you have a back up plan for the data2.
• You use etcd in Kubernetes as a backend for service delivery. It is one of the master components used for cluster management. You can run etcd in an external cluster or as a pod on your Kubernetes master. If you run it as an external cluster you can benefit from an extra layer of security and resiliency due to its isolation from the master3.

References:

• Operating etcd clusters for Kubernetes
• Kubernetes Components
• What Is etcd and How Is it Used in Kubernetes?

When you delete a pod managed by a Replica Set, the Replica Set will schedule a new pod to replace the deleted one. This is because the Replica Set’s purpose is to maintain a stable set of replica pods running at any given time. As such, it is often used to guarantee the availability of a specified number of identical pods1. The Replica Set controller monitors the number of pods it owns and creates or deletes pods as needed to reach the desired number. The Replica Set identifies its pods by using a selector that matches the pods’ labels2. Therefore, deleting a pod will reduce the number of pods that match the selector, and trigger the Replica Set to create a new pod with the same pod template3.

References:

• 1: ReplicaSet | Kubernetes
• 2: Labels and Selectors | Kubernetes
• 3: Pods, Deployments and Replica Sets: Kubernetes Resources Explained

When you create an API Rule for a service, the API Gateway Controller creates an Istio Virtual Service for you behind the kyma-gateway. The Istio Virtual Service defines the rules that control how requests for a service are routed within an Istio service mesh. By creating an API Rule, you have a higher-level abstraction of Istio VirtualServices and Oathkeeper Access Rules that allows you to provision services quickly and securely. References: Using the API Gateway to Expose Services, Exposing a Service in Kyma with API Rules

A pod in Kubernetes represents the smallest deployable units of computing that you can create and manage in Kubernetes. A pod is a group of one or more containers, with shared storage and network resources, and a specification for how to run the containers. A pod can run a single container or multiple containers that need to work together. Pods are the basic building blocks of Kubernetes applications, and they can be scaled, updated, and monitored by higher-level resources, such as deployments, services, or jobs. References: Pods | Kubernetes, What is a Kubernetes pod? - Red Hat, Kubernetes Pods - GeeksforGeeks