Interview Questions and Answers

Kubernetes is an open-source container orchestration platform that automates the deployment, scaling, and management of containerized applications. It helps in managing containerized applications in a clustered environment efficiently.

A Pod is the smallest and simplest unit in the Kubernetes object model. It represents a single instance of a running process in a cluster and can contain one or more containers.

A Deployment is a resource object in Kubernetes that provides declarative updates to applications. It allows you to describe a desired state for your application and automatically manages the deployment and scaling.

A Namespace is a way to divide cluster resources between multiple users or projects. It helps in organizing and isolating resources within a cluster.

Helm is a package manager for Kubernetes that simplifies the deployment and management of applications. A Helm Chart is a collection of pre-configured Kubernetes resources packaged for easy deployment.

Labels are key-value pairs attached to objects (e.g., Pods). Selectors are used to filter and find objects based on labels, facilitating grouping and categorization of resources.

A liveness probe is a mechanism to detect whether a container is still running. If the liveness probe fails, Kubernetes can restart the container to maintain application availability.

The HPA automatically adjusts the number of Pods in a deployment or replica set based on observed resource utilization, such as CPU usage or custom metrics.

The kubelet is the primary node agent that runs on each node in the cluster. It ensures that containers are running in a Pod and communicates with the Kubernetes master to manage the Pod lifecycle.

Key components include Master Node (API server, Controller manager, Scheduler), Worker Node (Kubelet, Kube Proxy), and etcd (distributed key-value store).

Pods share the same network namespace, allowing them to communicate via localhost. They can also use Services for communication, which provides a stable IP and DNS name for a set of Pods.

Services provide a stable endpoint for accessing a set of Pods. Types include ClusterIP (internal to the cluster), NodePort (exposes service on each node's IP), and LoadBalancer (provides an external IP and routes traffic to the service).

Ingress is an API object that manages external access to services within a cluster. It provides HTTP and HTTPS routing to services based on rules specified by the user.

A ConfigMap is a Kubernetes resource that allows you to decouple configuration artifacts from the container image, making it easier to manage configurations for different environments.

A Secret is used to store sensitive information such as passwords, API keys, and tokens. It ensures that confidential data is not exposed in the configuration or environment variables.

Controllers in Kubernetes are control loops that regulate the state of the system. Examples include ReplicaSet (ensures a specified number of replicas), and StatefulSet (maintains stateful applications).

RBAC is a Kubernetes feature that provides a flexible system for defining roles and permissions within a cluster. It allows administrators to control access to resources based on roles and role bindings.

HPA automatically adjusts the number of replica Pods in a deployment based on observed CPU utilization or custom metrics. It ensures optimal resource utilization and application performance.

An Init Container is a specialized container that runs before the main application container starts. It is often used for setup tasks, such as database migrations or configuration fetching.

Pod Affinity is a way to influence the scheduling of Pods based on the presence of other Pods. It allows you to ensure that Pods are co-located or spread across nodes.

A Helm Release is an instance of a Helm Chart deployed in a Kubernetes cluster. It represents a specific configuration of the application and can be upgraded, rolled back, or deleted independently.

Taints are used to repel Pods from nodes, while tolerations allow Pods to schedule on nodes with specific taints. This helps in dedicating nodes to specific workloads.

A Helm Release Chart is a package of pre-configured Kubernetes resources for deploying and managing an application using Helm. It includes templates for various resources like Pods, Services, and ConfigMaps.

Persistent Volumes are used to store data in a cluster independently of Pods. They are provisioned by administrators and can be dynamically or statically provisioned.

In a Rolling Deployment, new versions of the application are gradually rolled out to the instances, minimizing downtime. It ensures that the application is available throughout the deployment.

StatefulSets are used for stateful applications requiring stable network identities and persistent storage. Deployments are suitable for stateless applications that can scale horizontally.

A DaemonSet ensures that all or some nodes run a copy of a Pod, while a Deployment is used for stateless applications. DaemonSets are typically used for background tasks or system-level services.

Network Policies are used to control the communication between Pods. They define rules for incoming and outgoing traffic, allowing administrators to enforce network segmentation and security.

An Operator is a method of packaging, deploying, and managing a Kubernetes application. It extends the Kubernetes API to automate complex, stateful applications and services.

Resource Quotas allow cluster administrators to limit resource consumption in a namespace. It helps prevent individual projects or users from consuming excessive resources.