Advanced Kubernetes Interview Questions

23. What is the role of the kube-scheduler in Kubernetes?

This Kubernetes scheduler, a control plane mechanism, is in charge of assigning Pods to Nodes; it evaluates constraints and readily accessible assets to identify acceptable candidate Nodes for each Pod in the scheduling queue. Kube-scheduler, the default scheduler for Kubernetes, works within the control plane and is intended to provide users with the option to develop and implement their custom scheduling components.

24. Describe how a Horizontal Pod Autoscaler (HPA) works.

With a dedicated instance for each workflow, each configured Horizontal Pod Autoscaler works as part of a control loop, automatically changing the workloads’ shape to maintain the desired state by periodically contrasting its metrics to the user-configured target thresholds.

apiVersion: autoscaling/v2

kind: HorizontalPodAutoscaler

metadata:

name: webserver-mem-hpa

spec:

maxReplicas: 5

minReplicas: 1

scaleTargetRef:

apiVersion: apps/v1

kind: Deployment

name: webserver

metrics:

– type: Resource

resource:

name: memory

target:

type: Utilization

averageValue: 2Mi

25. Explain the concept of Custom Resources in Kubernetes.

Following a custom resource is installed, users can create and access its objects using kubectl, just like they do for built-in resources like Pods. A custom resource is an extension of the Kubernetes API that is not always available in a default Kubernetes installation. However, many core Kubernetes functions are now built using custom resources, making Kubernetes more modular. Custom resources can come and go in a running the cluster through dynamic registration, and cluster admins can update custom resources independently of the cluster.

26. How does Kubernetes handle security and access control?

Using robust access restrictions and encryption techniques, like Kubernetes Secrets or external key management systems, can help safeguard sensitive data kept within your cluster. To prevent unwanted access, data must be encrypted as it is in transit and at rest.

27. What is a Network Policy in Kubernetes?

Kubernetes Network Policies are an application-centric build that let you specify how pod is allowed to communicate with various network “entities” (we use the term “entity” here to avoid over change the more common terms such as “endpoints” and “services”, which have specific K8s connotations) over the network. Network Policies apply to the connection with pod on one or both sides, and are not relevant to any other connections.

28. Describe the role of a kube-proxy in the cluster.

Kube-Proxy is an important Kubernetes agent that stays on every cluster node. Its main function is to keep track of adjustments made to Service objects and the endpoints that correspond to them. Based on the changes made, it switches them into concrete network rules on the node.

29. What is a Helm chart, and how is it used?

Helm utilizes a packaging format called charts, which are collection of files which describe the cohesive set of Kubernetes resources. Whether you are deploying a simple component, like a memcached pod, or a complex web app stack which involves HTTP servers, databases, caches, and more, all the files you need are contained in a single chart. Helm chart packages provide all the resources you need to deploy an application to a Kubernetes cluster, which involves YAML configuration files for secrets, services, deployments, and config maps that provide the app’s desired state.

30. Explain the concept of Taints and Tolerations in Kubernetes.

Tolerances, when applied to pods, enable the scheduler to schedule them in the presence of matching taints. However, tolerating a pod does not ensure scheduling, as the scheduler considers other factors when making its decision. Node affinity is a property of Pods that either expresses a preference or sets a hard requirement to attract them to a specific set of nodes. Taints, on the other hand, work as the opposite, allowing a node to repel a specific group of pods.

apiVersion: v1

kind: Pod

metadata:

name: nginx

labels:

env: test

spec:

containers:

– name: nginx

image: nginx

imagePullPolicy: IfNotPresent

tolerations:

– key: “example-key”

operator: “Exists”

effect: “NoSchedule”

31. How does Kubernetes manage storage orchestration?

The Container Storage Interface (CSI) is the standard to establish device-independent relationships across block and file storage systems and containerized workloads. In essence, CSI allows storage interfaces to be declared to be implemented by containers.

32. Describe the use of init containers in Kubernetes.

This page provides an overview of init containers, which are specialized containers that carry out in front of app containers in a Pod. You can specify init containers in the Pod specification as well as to the containers array (which describes app containers). Init containers can contain utilities or setup scripts that aren’t present in an app image. Resource limitations, volumes, and security settings are just a few of the characteristics and functions that app containers support in it containers.

33. In Kubernetes, what are the various services available?

Kubernetes supports a number of services, include the following: 1) Cluster IP, 2) Node Port, 3) Load Balancer, & 4) External Name Creation.

1. Cluster IP Service

A ClusterIP service in Kubernetes provides a stable virtual IP address (Cluster IP) to the service, allowing internal communication between various parts in the Kubernetes cluster, it exposes a set of Pods within the cluster to other objects in the cluster.

2. Node Port Service

A NodePort service in Kubernetes is a type of service that allows a group of Pods accessible to external customers on an allocated port on all cluster nodes.

3. Load Balancer service

An external load balancer is automatically provided by a LoadBalancer service in Kubernetes to distribute incoming traffic between the Pods when a group of Pods are accessible to the outside world.

4. External Name Creation Service

An ExternalName service in Kubernetes works as an alias which allows pods inside the cluster to contact services outside cluster using a user-defined DNS name. External name provides DNS-based service discovery to map a service to an external DNS name.

Also Read: Kubernetes – Images

Kubernetes is a powerful open-source platform for automating deployment, scaling, and operations of application containers across clusters of hosts. It provides a container-centric infrastructure that is efficient, making it a leading choice for managing complex applications. Derived from the Greek word meaning “captain,” “helmsman,” or “governor,” Kubernetes has become indispensable in the world of cloud-native applications. With its automation, scalability, and ease of deployment, Kubernetes offers unparalleled efficiency for developers and operations teams alike. Kubernetes is extensively used by top companies like Google, Red Hat, VMware, IBM, and many others due to its robust features and exceptional performance.

In this article, we will provide the Top 40 Kubernetes Interview Questions and Answers tailored for both freshers and experienced professionals. Here, we cover everything, including fundamental Kubernetes concepts, Kubernetes architecture, pods, StatefulSets, Monitoring and Logging, deployment strategies, and more, that will surely help you crack DevOps interviews.