Saturday 25 August 2018

Kubernetes Interview Questions And Answers

Kubernetes Interview Questions
Kubernetes is anOpen source software
Kubernetes is aSystem for automating deployment, scaling and management of containerized applications
Kubernetes wasOriginally designed by Google and now maintained by the Cloud Native Computing Foundation.
Kubernetes canIt aims to provide a platform for automating deployment, scaling, and operations of application containers.
Kubernetes developed byGoogle
Kubernetes LicenseApache License 2.0
Kubernetes has written inGo Programming
Kubernetes Interview Question # 1) What is the Kubernetes?
A) Kubernetes is an open-source system for automating deployment, scaling, and management of containerized applications. It groups containers that make up an application into logical units for easy management and discovery. 

Kubernetes Interview Question # 2) What is Kubernetes and how to use it?
A) Kubernetes is an open-source platform designed to automate deploying, scaling, and operating application containers. With Kubernetes, you are able to quickly and efficiently respond to customer demand: Deploy your applications quickly and predictably.

Kubernetes Interview Question # 3) What is the meaning of Kubernetes?
A) Kubernetes (commonly referred to as “K8s”) is an open-source system for automating deployment, scaling and management of containerized applications that was originally designed by Google and donated to the Cloud Native Computing Foundation.

Docker Kubernetes Interview Questions For Experienced

Kubernetes Interview Question # 4) What is a docker?
A) Docker container is an open source software development platform. Its main benefit is to package applications in “containers,” allowing them to be portable among any system running the Linux operating system (OS).

Kubernetes Interview Question # 5) What is orchestration in software?
A) Application Orchestration. Application or service orchestration is the process of integrating two or more applications and/or services together to automate a process, or synchronize data in real-time. Often, point-to-point integration may be used as the path of least resistance.

Kubernetes Questions # 6) What is a cluster in Kubernetes?
A) These master and node machines run the Kubernetes cluster orchestration system. A container cluster is the foundation of Container Engine: the Kubernetesobjects that represent your containerized applications all run on top of a cluster.

Interview Questions on Kubernetes # 7) What is a swarm in Docker?
A) Docker Swarm is a clustering and scheduling tool for Docker containers. With Swarm, IT administrators and developers can establish and manage a cluster ofDocker nodes as a single virtual system.

Kubernetes Openshift Interview Question # 8) What is Openshift?
A) OpenShift Online is Red Hat’s public cloud application development and hosting platform that automates the provisioning, management and scaling of applications so that you can focus on writing the code for your business, startup, or big idea.

Advanced Kubernetes Interview Questions

Docker and Kubernetes Interview Question # 9) What is a namespace in Kubernetes?
A) Namespaces are intended for use in environments with many users spread across multiple teams, or projects. Namespaces are a way to divide cluster resources between multiple uses (via resource quota). In future versions of Kubernetes, objects in the same namespace will have the same access control policies by default.

Kubernetes Interview Question # 10) What is a node in Kubernetes?
A) A node is a worker machine in Kubernetes, previously known as a minion. A nodemay be a VM or physical machine, depending on the cluster. Each node has the services necessary to run pods and is managed by the master components. The services on a node include Docker, kubelet and kube-proxy.

Kubernetes Interview Question # 11) What is Docker and what does it do?
A) Docker is a tool designed to make it easier to create, deploy, and run applications by using containers. Containers allow a developer to package up an application with all of the parts it needs, such as libraries and other dependencies, and ship it all out as one package.

Kubernetes Interview Question # 12) What is a Heapster?
A) Heapster is a cluster-wide aggregator of monitoring and event data. It supports Kubernetes natively and works on all Kubernetes setups, including our Deis Workflow setup.

Kubernetes Interview Question # 13) Why do we use Docker?
A) Docker provides this same capability without the overhead of a virtual machine. It lets you put your environment and configuration into code and deploy it. The same Docker configuration can also be used in a variety of environments. This decouples infrastructure requirements from the application environment.

Kubernetes Interview Question # 14) What is a docker in cloud?
A) A node is an individual Linux host used to deploy and run your applications. Docker Cloud does not provide hosting services, so all of your applications, services, and containers run on your own hosts. Your hosts can come from several different sources, including physical servers, virtual machines or cloud providers.

Kubernetes Interview Question # 15) What is a cluster of containers?
A) A container cluster is a set of Compute Engine instances called nodes. It also creates routes for the nodes, so that containers running on the nodes can communicate with each other. The Kubernetes API server does not run on your cluster nodes. Instead, Container Engine hosts the API server.

Real-Time Kubernetes Scenario Based Interview Questions

Kubernetes Interview Questions # 16) What is the Kubelet?
A) Kubelets run pods. The unit of execution that Kubernetes works with is the pod. A pod is a collection of containers that share some resources: they have a single IP, and can share volumes.

Kubernetes Interview Questions # 17) What is Minikube?
A) Minikube is a tool that makes it easy to run Kubernetes locally. Minikube runs a single-node Kubernetes cluster inside a VM on your laptop for users looking to try out Kubernetes or develop with it day-to-day.

Kubernetes Interview Questions # 18) What is Kubectl?
A) kubectl is a command line interface for running commands against Kubernetes clusters. This overview covers kubectl syntax, describes the command operations, and provides common examples. For details about each command, including all the supported flags and subcommands, see the kubectl reference documentation.

Kubernetes Interview Questions # 19) What is the Gke?
A) Google Container Engine (GKE) is a management and orchestration system for Docker container and container clusters that run within Google’s public cloud services. Google Container Engine is based on Kubernetes, Google’s open source container management system.

Kubernetes Interview Questions # 20) What is k8s?
A) Kubernetes, also sometimes called K8S (K – eight characters – S), is an open source orchestration framework for containerized applications that was born from the Google data centers.

Kubernetes Interview Questions # 21) What is KUBE proxy?
A) Synopsis. The Kubernetes network proxy runs on each node. Service cluster ips and ports are currently found through Docker-links-compatible environment variables specifying ports opened by the service proxy. There is an optional addon that provides cluster DNS for these cluster IPs.

Kubernetes Interview Questions # 22) Which process runs on Kubernetes master node?
A) Kube-apiserver process runs on Kubernetes master node.

Kubernetes Interview Questions # 23) Which process runs on Kubernetes non-master node?
A) Kube-proxy process runs on Kubernetes non-master node.

Kubernetes Interview Questions # 24) Which process validates and configures data for the api objects like pods, services?
A) kube-apiserver process validates and configures data for the api objects.

Kubernetes Interview Questions # 25) What is the use of kube-controller-manager?
A) kube-controller-manager embeds the core control loop which is a non-terminating loop that regulates the state of the system.

Kubernetes Interview Questions # 26) Kubernetes objects made up of what?
A) Kubernetes objects are made up of Pod, Service and Volume.

Kubernetes Interview Questions # 27) What are Kubernetes controllers?
A) Kubernetes controllers are Replicaset, Deployment controller.

Kubernetes Interview Questions # 28) Where Kubernetes cluster data is stored?
A) etcd is responsible for storing Kubernetes cluster data.

Kubernetes Interview Questions # 29) What is the role of kube-scheduler?
A) kube-scheduler is responsible for assigning a node to newly created pods.

Kubernetes Interview Questions # 30) Which container runtimes supported by Kubernetes?
A) Kubernetes supports docker and rkt container runtimes.

Kubernetes Interview Questions # 31) What are the components interact with Kubernetes node interface?
A) Kubectl, Kubelet, and Node Controller components interacts with Kubernetes node interface.

Q: What is Kubernetes?
A:
 Kubernetes is Google's open source system for managing Linux containers across private, public and hybrid cloud environments.
It is a portable, extensible open-source platform for managing containerized workloads and services, that facilitates both declarative configuration and automation. 
It has a large, rapidly growing ecosystem. Kubernetes services, support, and tools are widely available. It contains tools for orchestration, service discovery and load balancing that can be used with Docker and Rocket containers. As needs change, a developer can move container workloads in Kubernetes to another cloud provider without changing the code. 
It helps automates the deployment, scaling, maintenance, scheduling and operation of multiple application containers across clusters of nodes. 

Q: What are the advantages of Kubernetes?
A:
 The advantages of using Kubernetes are as follows-
  • Automated Scheduling- Kubernetes provides advanced scheduler to launch container on cluster nodes. Kubernetes role is to automate the distribution (scheduling) of application containers across a cluster in an efficient way.
  • Auto Healing Capabilities - Kubernetes auto-healing mechanisms, such as auto-restarting, re-scheduling, and replicating containers
  • Automated Rollback - Sometimes you may want to rollback a Deployment; for example, when the Deployment is not stable, such as crash looping. By default, all of the Deployments rollout history is kept in the system so that you can rollback anytime you want.
  • Horizontal Scaling - Autoscaling is one of the key features in Kubernetes cluster. It is a feature in which the cluster is capable of increasing the number of nodes as the demand for service response increases and decrease the number of nodes as the requirement decreases.

Q: What is Docker?
A:
 Consider a scenario - You have just joined a new organization as a developer. You will now have to setup the project with the assistance of a fellow developer. He suggests you follow certain steps for setting up the required environment and then start the project deployable like a WAR. You do the same, but keep getting some or other issues regarding environment configuration. May be even your fellow developer has forgot some configuration property he might have set. Well you are stuck in such a situation. This is known as Dependency Hell. Other similar scenario of this dependency hell are - The application is running on my dev machine but not in production. Dont know what issue is. There is also other scenarios like Matrix of Hell. But this is mostly related to DEVOPS people. Docker to the rescue.
Docker is a tool designed to make it easier to create, deploy, and run applications by using containers. Docker Tutorials 

Q: How to deploy Spring Boot WAR to Docker?
A:
 Deploying Spring Based WAR Application to Docker 

Q: How to deploy Spring Boot JAR to Docker?
A:
 Deploying Spring Based JAR Application to Docker 

Q: How to deploy multiple microservices to Docker?
A:
 Deploying Multiple Spring Boot Microservices using Docker Networking

Q: What are the scenarios in which a Java Developer will use Docker?
A:
Following scenarios a java developer can use docker-
  • Sharing development workspace, with preconfigured development environment.
  • Continuous integration is one of the most popular use cases for Docker. Teams looking build and deploy their applications quickly use Docker, combined with ecosystem tools like Jenkins, to drive apps from dev, testing staging and into production without having to change any code.
  • Running UAT's using Docker

Q: What are namespaces in Kubernetes?
A:
 Kubernetes supports multiple virtual clusters backed by the same physical cluster. These virtual clusters are called namespaces. Kubernetes allows use of multiple namespaces.

Q: What is a node in Kubernetes?
A:
 A node is a worker machine in Kubernetes, previously known as a minion. A node may be a VM or physical machine, depending on the cluster. Each node has the services necessary to run pods and is managed by the master components. The services on a node include the container runtime, kubelet and kube-proxy. 

Q: What is a pod in Kubernetes?
A:
 A Kubernetes pod is a group of containers that are deployed together on the same host. If you frequently deploy single containers, you can generally replace the word "pod" with "container" and accurately understand the concept. 

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