Question 1

What is Kubernetes?

Accepted Answer

Kubernetes (K8s) is an open-source container orchestration platform that automates the deployment, scaling, and management of containerized applications.

Question 2

Why do we need Kubernetes?

Accepted Answer

As applications grew from single monoliths to microservices, managing thousands of containers manually became impossible. Kubernetes provides a framework to run distributed systems resiliently, handling failovers, scaling, and load balancing automatically.

Question 3

What are the main components of Kubernetes Architecture?

Accepted Answer

Kubernetes follows a client-server architecture. It has a control plane (Master Node) consisting of kube-apiserver, etcd, kube-scheduler, and kube-controller-manager. It also has Worker Nodes consisting of kubelet, kube-proxy, and a container runtime.

Question 4

What is a Pod?

Accepted Answer

A Pod is the smallest and simplest execution unit in Kubernetes. It encapsulates one or more containers, storage resources, a unique network IP, and options that govern how the container(s) should run.

Question 5

What is a Node in Kubernetes?

Accepted Answer

A Node is a worker machine in Kubernetes (previously known as a minion). It may be a VM or a physical machine, depending on the cluster. Each node contains the services necessary to run Pods, managed by the control plane.

Question 6

What is kubelet?

Accepted Answer

The kubelet is the primary 'node agent' that runs on each worker node. It registers the node with the apiserver and ensures that containers described in PodSpecs are running and healthy.

Question 7

What is kube-proxy?

Accepted Answer

kube-proxy is a network proxy that runs on each node in your cluster, implementing part of the Kubernetes Service concept. It maintains network rules on nodes, allowing network communication to your Pods.

Question 8

What is the role of kube-apiserver?

Accepted Answer

The API server is the front end for the Kubernetes control plane. It exposes the Kubernetes API, handles REST operations, and provides the frontend to the cluster's shared state through which all other components interact.

Question 9

What is etcd?

Accepted Answer

etcd is a consistent, highly-available key-value store used as Kubernetes' backing store for all cluster data. It holds the desired state and current state of the entire cluster.

Question 10

What is kube-scheduler?

Accepted Answer

The scheduler watches for newly created Pods that have no Node assigned. For every unassigned Pod, the scheduler finds the best Node for that Pod to run on based on resource requirements, constraints, and policies.

Question 11

What is a ReplicaSet?

Accepted Answer

A ReplicaSet's purpose is to maintain a stable set of replica Pods running at any given time. It guarantees the availability of a specified number of identical Pods.

Question 12

What is a Deployment in Kubernetes?

Accepted Answer

A Deployment provides declarative updates for Pods and ReplicaSets. You describe a desired state in a Deployment, and the Deployment Controller changes the actual state to the desired state at a controlled rate (e.g., for rolling updates).

Question 13

What is a Kubernetes Service?

Accepted Answer

A Service is an abstract way to expose an application running on a set of Pods as a network service. It provides a stable IP address and DNS name to access the dynamically changing Pod IPs.

Question 14

What are the different types of Kubernetes Services?

Accepted Answer

The main types are: ClusterIP (default, internal only), NodePort (exposes on each Node's IP at a static port), LoadBalancer (provisions a cloud provider's load balancer), and ExternalName (maps the Service to a DNS name).

Question 15

What are Namespaces?

Accepted Answer

Namespaces provide a mechanism for isolating groups of resources within a single cluster. They are intended for use in environments with many users spread across multiple teams or projects (like resource quotas).

Question 16

What is kubectl?

Accepted Answer

kubectl is the command-line tool for interacting with the Kubernetes API server. It allows you to run commands against Kubernetes clusters to deploy apps, inspect and manage cluster resources, and view logs.

Question 17

How do you view all pods in the default namespace?

Accepted Answer

You use the `kubectl get pods` command.
Code Example:
kubectl get pods

Question 18

How do you view pods across all namespaces?

Accepted Answer

You use the `--all-namespaces` or `-A` flag.
Code Example:
kubectl get pods -A

Question 19

What is a Container Runtime?

Accepted Answer

The container runtime is the software that is responsible for running containers. Kubernetes supports several runtimes: containerd, CRI-O, and any implementation of the Kubernetes CRI (Container Runtime Interface).

Question 20

What is Minikube?

Accepted Answer

Minikube is a tool that allows you to run a single-node Kubernetes cluster locally on your personal computer (including Windows, macOS, and Linux PCs) so that you can try out Kubernetes or develop with it daily.

Question 21

What is a DaemonSet?

Accepted Answer

A DaemonSet ensures that a copy of a Pod runs on all (or some) Nodes in the cluster. As nodes are added to the cluster, Pods are added to them. It is typically used for cluster storage daemons or log collection daemons.

Question 22

What is a StatefulSet?

Accepted Answer

StatefulSet is the workload API object used to manage stateful applications. It manages the deployment and scaling of a set of Pods, and provides guarantees about the ordering and uniqueness of these Pods (sticky identity).

Question 23

What are Labels and Selectors?

Accepted Answer

Labels are key/value pairs attached to objects, such as pods, used to specify identifying attributes. Label Selectors are the core grouping primitive in Kubernetes, allowing the user/system to identify a set of objects.

Question 24

What is a ConfigMap?

Accepted Answer

A ConfigMap is an API object used to store non-confidential data in key-value pairs. Pods can consume ConfigMaps as environment variables, command-line arguments, or as configuration files in a volume.

Question 25

What is a Secret in Kubernetes?

Accepted Answer

A Secret is an object that contains a small amount of sensitive data such as a password, a token, or a key. This allows you to manage sensitive information separately from pod specifications or container images.

Question 26

How does a Rolling Update work in deployments?

Accepted Answer

A Rolling Update allows Deployments' update to take place with zero downtime by incrementally replacing Pods instances with new ones. The new Pods are scheduled on Nodes with available resources.

Question 27

What is an Ingress in Kubernetes?

Accepted Answer

Ingress is an API object that manages external access to the services in a cluster, typically HTTP/HTTPS. It provides load balancing, SSL termination, and name-based virtual hosting.

Question 28

What is an Ingress Controller?

Accepted Answer

An Ingress controller is responsible for fulfilling the Ingress, usually with a load balancer (like NGINX or HAProxy). Unlike other controllers that run as part of the kube-controller-manager, Ingress controllers are not started automatically with a cluster.

Question 29

Explain Liveness and Readiness Probes.

Accepted Answer

A Liveness probe checks if a container is running. If it fails, kubelet kills the container and it is subject to its restart policy. A Readiness probe checks if a container is ready to respond to requests. If it fails, the endpoints controller removes the Pod's IP from the endpoints of all Services.

Question 30

What is a Job in Kubernetes?

Accepted Answer

A Job creates one or more Pods and ensures that a specified number of them successfully terminate. It tracks successful completions. When a specified number of successful completions is reached, the task (ie, Job) is complete.

Kubernetes (K8s) Orchestration Master

Difficulty Filters

Tools & Options

What is Kubernetes?

Why do we need Kubernetes?

What are the main components of Kubernetes Architecture?

What is a Pod?

What is a Node in Kubernetes?

What is kubelet?

What is kube-proxy?

What is the role of kube-apiserver?

What is etcd?

What is kube-scheduler?

What is a ReplicaSet?

What is a Deployment in Kubernetes?

What is a Kubernetes Service?

What are the different types of Kubernetes Services?

What are Namespaces?

What is kubectl?

How do you view all pods in the default namespace?

How do you view pods across all namespaces?

What is a Container Runtime?

What is Minikube?

What is a DaemonSet?

What is a StatefulSet?

What are Labels and Selectors?

What is a ConfigMap?

What is a Secret in Kubernetes?

How does a Rolling Update work in deployments?

What is an Ingress in Kubernetes?

What is an Ingress Controller?

Explain Liveness and Readiness Probes.

What is a Job in Kubernetes?

What is a CronJob?

What is Role-Based Access Control (RBAC)?

What is the difference between a Role and a ClusterRole?

What is a Persistent Volume (PV)?

What is a Persistent Volume Claim (PVC)?

What are Storage Classes?

What is Helm in the context of Kubernetes?

Explain Horizontal Pod Autoscaler (HPA).

What is the Cluster Autoscaler?

What is a Headless Service?

What are Taints and Tolerations?

What is Node Affinity?

What is Pod Affinity/Anti-Affinity?

What is an Init Container?

What is a Service Account?

How does resource limits and requests work?

What is a Multi-container Pod?

What is the pause container in a Pod?

How do you rollback a Deployment?

What is Kubeadm?

What is the Control Plane failure impact?

Explain the role of Mutating and Validating Admission Controllers.

How does Kubernetes implement Service Discovery internally?

What are Custom Resource Definitions (CRDs)?

What is the Kubernetes Operator Pattern?

Explain Network Policies.

What is priority and preemption in Kubernetes?

What happens during a graceful pod termination?

What is a PodDisruptionBudget (PDB)?

How do you achieve zero downtime during Node upgrades?

What is the Container Network Interface (CNI)?

What is the Container Storage Interface (CSI)?

What is etcd backup and why is it critical?

Explain how Service Mesh integrates with Kubernetes.

What is a StatefulSet's VolumeClaimTemplate?

What is OOMKilled and why does it happen?

What is a LimitRange?

What is a ResourceQuota?

How does iptables relate to kube-proxy?

What are Ephemeral Containers?

Explain the `ImagePullPolicy`.

What are EndpointSlices?

How does Kubernetes handle certificates?

What is Server-Side Apply?

What is the Downward API?

How do you forcefully delete a Pod that is stuck in Terminating status?

How do you check the resource usage (CPU/Memory) of Pods?