Day 37 Task: Kubernetes Important interview Questions.

This is #90DaysofDevopschallenge under the guidance of Shubham Londhe sir.

Introduction

Welcome to Day 37 of your 90DaysOfDevOps challenge!

Today, we're delving into Kubernetes, exploring key interview questions to boost your expertise and confidence in managing Kubernetes environments. Let's dive right in!

Let's tackle each question with precision and clarity:

1.What is Kubernetes and why it is important?

• Kubernetes is an open-source container orchestration platform designed to automate the deployment, scaling, and management of containerized applications. Its importance lies in its ability to simplify complex containerized environments, enhance resource utilization, and streamline application deployment processes, fostering agility and scalability in modern infrastructure.

2.What is difference between docker swarm and kubernetes?

• Docker Swarm and Kubernetes are both container orchestration tools, but they differ in various aspects. While Docker Swarm is native to Docker, offering simplicity and ease of use for smaller-scale deployments, Kubernetes provides advanced features for large-scale container orchestration, including robust management capabilities, automated scaling, and extensive ecosystem support.

3.How does Kubernetes handle network communication between containers?

• Kubernetes employs a network overlay model to facilitate communication between containers within a cluster. It creates a virtual network that spans across all nodes, allowing containers to communicate seamlessly through network policies and service discovery mechanisms.

4.How does Kubernetes handle scaling of applications?

• Kubernetes enables horizontal scaling of applications through the concept of replica sets and deployment configurations. By dynamically adjusting the number of replica pods based on resource demands and defined scaling policies, Kubernetes ensures optimal performance and resource utilization for applications.

5.What is a Kubernetes Deployment and how does it differ from a ReplicaSet?

• A Kubernetes Deployment manages the lifecycle of application pods, facilitating updates, rollbacks, and scaling operations. It abstracts away the underlying complexities of managing replica sets, providing declarative configuration and version control capabilities for application deployments.

6.Can you explain the concept of rolling updates in Kubernetes?

• Rolling updates in Kubernetes involve gradually transitioning from one version of an application to another without incurring downtime. Kubernetes achieves this by incrementally updating pods while ensuring that a sufficient number of healthy instances are available to maintain application availability and stability.

7.How does Kubernetes handle network security and access control?

• Kubernetes offers robust network security features, including network policies, pod security policies, and role-based access control (RBAC). These mechanisms enable administrators to define and enforce granular access controls, secure communication channels, and restrict unauthorized access within the Kubernetes cluster.

8.Can you give an example of how Kubernetes can be used to deploy a highly available application?

• Kubernetes can deploy a highly available application by leveraging features such as pod replicas, load balancing, and auto-scaling. For instance, deploying a stateful application with multiple replicas across multiple nodes, coupled with health checks and service discovery, ensures continuous availability and resilience against failures.

9.What is namespace is kubernetes? Which namespace any pod takes if we don't specify any namespace?

• A namespace in Kubernetes provides a logical boundary for organizing and isolating resources within a cluster. If a pod is not specified with a namespace, it defaults to the 'default' namespace, which is the primary namespace for most Kubernetes resources.

10.How ingress helps in kubernetes?

• Ingress in Kubernetes serves as an API object that manages external access to services within the cluster. It enables the definition of routing rules, load balancing, and SSL termination for incoming traffic, simplifying the configuration of external access to applications deployed in the cluster.

11.Explain different types of services in kubernetes?

• Kubernetes offers various types of services, including ClusterIP, NodePort, LoadBalancer, and ExternalName. Each service type caters to specific use cases, such as internal service discovery, exposing services externally, and integrating with external load balancers.

12.Can you explain the concept of self-healing in Kubernetes and give examples of how it works?

• Self-healing in Kubernetes refers to the platform's ability to detect and recover from pod failures automatically. By continuously monitoring the health and status of pods, Kubernetes orchestrates self-healing mechanisms such as pod rescheduling, container restarts, and node evacuation to maintain application reliability and availability.

13.How does Kubernetes handle storage management for containers?

• Kubernetes offers persistent volume (PV) and persistent volume claim (PVC) abstractions for managing storage resources within the cluster. PVs represent storage volumes provisioned by administrators, while PVCs enable applications to request and consume storage dynamically based on defined storage classes and access modes.

14.How does the NodePort service work?

• The NodePort service type in Kubernetes exposes a service on a static port across all nodes in the cluster. It maps the specified NodePort to the port exposed by the service, allowing external traffic to reach the service through any node's IP address and the designated NodePort.

15.What is a multinode cluster and single-node cluster in Kubernetes?

• A multinode cluster in Kubernetes consists of multiple worker nodes interconnected to form a distributed infrastructure for deploying and managing containerized applications. In contrast, a single-node cluster comprises only a single worker node, suitable for development, testing, or lightweight production environments.

16.Difference between create and apply in kubernetes?

• The 'kubectl create' command in Kubernetes creates a new resource based on the provided configuration file, while the kubectl apply command applies changes to existing resources or creates new resources if they do not exist, ensuring idempotent resource management and configuration synchronization.