Kubernetes - Interview Question Set-4

 

Question-31: What is a label in Kubernetes and how is it used?

Answer: A label in Kubernetes is a key-value pair attached to resources such as pods, services, and nodes. Labels are used to identify and group resources and to provide metadata about the resources. Labels can be used to select a group of resources and perform operations on them, such as scaling or rolling updates.

Question-32: How does Kubernetes perform load balancing for applications?

Answer: Kubernetes performs load balancing for applications using services. A service in Kubernetes is an abstraction over a set of pods that provides a stable IP address and DNS name. Services expose pods to the network and perform load balancing across the pods. When a client makes a request to a service, the service load balances the request to one of the pods.

Question-33: What is a PersistentVolume in Kubernetes and what is it used for?

Answer: A PersistentVolume in Kubernetes is a resource that represents a piece of storage in the cluster that can be dynamically provisioned or statically provisioned. PersistentVolumes are used to provide storage for pods that requires persistence across pod restarts and failures.

Question-34: A cluster administrator needs to provide a stable IP address for a database that is running in a pod. What type of Service should the administrator use to accomplish this?

Answer: A ClusterIP Service should be used to provide a stable IP address for the database pod. ClusterIP Services provide stable IP addresses for pods within the cluster, making it easy to provide stable IP addresses for databases and other critical applications running in the cluster.

Question-35: What is an ingress in Kubernetes and what is it used for?

Answer: An ingress in Kubernetes is a resource that allows external traffic to reach the services in a cluster. It defines rules for routing incoming HTTP and HTTPS traffic to services in the cluster. Ingress provides a way to expose multiple services under a single IP address and DNS name, and it provides features such as SSL termination and URL-based routing.

Question-36: What is an admission controller in Kubernetes and what is it used for?

Answer: An admission controller in Kubernetes is a pluggable component that intercepts requests to the API server and performs checks and validations on the incoming requests. Admission controllers are used to enforce policies and constraints on resources in the cluster, such as validating resource specifications and enforcing access control policies.

Question-37: How does Kubernetes perform rolling updates for applications?

Answer: Kubernetes performs rolling updates for applications using the concept of Deployments. A Deployment in Kubernetes is a higher-level resource that manages a set of replicas of a single application. When you update a Deployment, it creates new replicas with the updated version of the application and gradually replaces the old replicas with the new ones, one at a time. This rolling update process ensures that there is no downtime for the application during the update.

Question-38: What is a PersistentVolumeClaim in Kubernetes and what is it used for?

Answer: A PersistentVolumeClaim in Kubernetes is a resource that represents a request for storage by a pod. PersistentVolumeClaims are used to request a specific amount of storage from the PersistentVolumes in the cluster. When a PersistentVolumeClaim is created, Kubernetes matches the claim to an available PersistentVolume and binds the claim to the volume.

Question-39: What is a NodePort Service in Kubernetes and what is it used for?

Answer: A NodePort Service in Kubernetes is a type of Service that exposes pods to the network by opening a port on every node in the cluster. NodePort Services are used to expose pods to the network and to provide a stable endpoint for clients to access the pods from outside the cluster.

Question-40: What is a pod security policy in Kubernetes and what is it used for?

Answer: A pod security policy in Kubernetes is a resource that defines the security requirements for pods in the cluster. Pod security policies are used to control the security context of pods, and to define the security constraints for containers in the pods. Pod security policies provide a way to enforce security best practices for containers, and to ensure that pods meet specific security requirements.