SAP Certified Development Associate C_KYMD_01 Reddit Questions

 A Persistent Volume Claim (PVC) is a request for storage by a user. It is similar to a Pod, which is a request for compute resources by a user. A PVC enables a Pod to consume a slice of the available storage in the cluster without knowing the details of the underlying storage infrastructure. A PVC is associated with a StorageClass, which defines the type and characteristics of the storage. A PVC is also bound to a Persistent Volume (PV), which is an abstraction of the physical or cloud-based storage resource. A PV is created by the cluster administrator and has a lifecycle independent of any Pod. A PVC can specify the size, access mode, and storage class of the PV it requires. Before deploying an application that needs persistent state, a user must create a PVC for the Pod that will run the application. The PVC will then be automatically bound to a suitable PV by the cluster, or dynamically provisioned if the storage class supports it. The Pod can then mount the PVC as a volumeand access the persistent storage12345. References: Persistent Volumes | Kubernetes, How Kubernetes Persistent Volume Claims Work - CBT Nuggets, Exploring Kubernetes Storage: Persistent Volumes and Persistent Volume Claims - Atatus, Configure a Pod to Use a PersistentVolume for Storage | Kubernetes, kubernetes - How to mount a persistent volume on a Deployment/Pod using PersistentVolumeClaim? - Stack Overflow.

 Some of the features of Kubernetes are:

• Immutability and self-healing: Kubernetes treats pods as immutable, meaning that they are not modified after they are created. Instead, pods are replaced with new ones when they need to be updated or repaired. This ensures that the pods are always in a consistent and predictable state. Kubernetes also monitors the health and availability of the pods and automatically restarts, reschedules, or replicates them if they fail or become unresponsive1.
• Extensibility and ecosystem: Kubernetes is designed to be extensible and modular, allowing users to customize and extend its functionality according to their needs. Kubernetes supports various extensions, such as custom resources, operators, admission controllers, schedulers, network plugins, storage plugins, and more. Kubernetes also has a large and vibrant ecosystem of tools, services, and applications that are built on top of or integrate with it2.
• Automated rollouts and rollbacks: Kubernetes enables users to deploy and update their applications with zero downtime, using declarative configuration and rolling updates. Kubernetes ensures that only a certain number of pods are changed at a time, and that the new pods are ready before terminating the old ones. Kubernetes also tracks the history of each update and allows users to roll back to a previous version if something goes wrong3.

References:

• 1: Pods | Kubernetes
• 2: Extending Kubernetes | Kubernetes
• 3: Deployments | Kubernetes

 The kubectl command to list pods with the exact label “env-dev” is kubectl get pods -l env=dev. The -l or --selector flag allows you to filter pods by label selectors, which are key-value pairs that are attached to pods. The = operator matches pods that have the exact label value specified. The -L or --label-columns flag adds a column with the value of the specified label(s) to the output, but does not filter the pods. The -I or --ignore-not-found flag returns an exit code of 0 when no resources are found, but does not affect the output. The -l env-dev flag is invalid, as it does not specify a label value. References: 6, 7, 9

 The API Gateway in Kyma is a custom-configured Istio Ingress Gateway that is installed in the kyma-system namespace called kyma-gateway. Istio is an open-source project that provides a service mesh for microservices. It enables traffic management, security, observability, and policy enforcement for the services in the cluster. The API Gateway uses Istio resources to expose and secure APIs for the workloads in Kyma. References: Using the API Gateway to Expose Services, SAP BTP, Kyma Runtime API Gateway future architecture based on Istio, GitHub - kyma-project/api-gateway.