Q. What is Kubernetes, and why is it used?
Kubernetes is a popular open-source orchestration tool for managing and deploying containerized applications. It provides a way to automate the deployment, scaling, and management of applications across multiple hosts, making it easier to manage large, complex distributed systems.
Q. What are the core components of Kubernetes, and what are their roles?
The core components of Kubernetes include the API server, etcd, kubelet, kube-proxy, and the controller manager. The API server is the central management hub for Kubernetes, while etcd is a distributed key-value store that stores configuration data. The kubelet runs on each node in the cluster and is responsible for managing containers. Kube-proxy is a network proxy that runs on each node in the cluster, while the controller manager manages various controllers that automate the cluster's behavior.
Q. What is a Pod in Kubernetes?
A Pod is the smallest 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. Pods provide a way to encapsulate and manage application processes in a single, cohesive unit.
Q. Wat is a Kubernetes ReplicaSet?
A ReplicaSet is a Kubernetes object that ensures a specified number of identical replicas of a Pod are running at any given time. It provides fault tolerance and scalability by automatically scaling the number of replicas up or down as needed.
Q. What is a Kubernetes Deployment, and how is it different from a ReplicaSet?
A Kubernetes Deployment is an object that manages a ReplicaSet and provides declarative updates to Pods and ReplicaSets. Deployments allow for rolling updates and rollbacks of a Pod's container image or configuration. A Deployment is higher-level abstraction than a ReplicaSet and provides more functionality, such as automated rollouts and rollbacks.
While ReplicaSets in Kubernetes provide automatic scaling and self-healing capabilities, they do not provide declarative updates like Deployments.
Q. What is Rolling Update?
A rolling update is a technique used to update a Kubernetes Deployment or ReplicaSet in a way that ensures that the update is applied gradually, one replica at a time while minimizing downtime and maintaining the availability of the application.
Q. What is a Kubernetes Service, and what is its purpose?
A Kubernetes Service is an object that provides a stable IP address and DNS name for a set of Pods in a cluster. It allows clients to connect to the Pods using a single IP address or DNS name, even as Pods are added or removed. Services provide load balancing and service discovery functionality for applications running in a Kubernetes cluster.
Q. What are Kubernetes Namespaces, and how are they used?
Kubernetes Namespaces provide a way to divide a Kubernetes cluster into multiple virtual clusters. They allow different teams or projects to use the same physical cluster while keeping their resources separate and isolated. Namespaces provide a way to organize resources, apply resource quotas, and set access control policies.
Q. What is a Kubernetes ConfigMap, and how is it used?
A Kubernetes ConfigMap is an object that provides a way to store configuration data in key-value pairs that can be consumed by Kubernetes Pods. It allows you to decouple configuration data from the container images, making it easier to manage and update configurations separately from the application code. ConfigMaps can be used to configure environment variables, command-line arguments, or configuration files for Pods.
Q. What is a Kubernetes Secret, and how is it used?
A Kubernetes Secret is an object that provides a way to store sensitive data, such as passwords or API keys, in a Kubernetes cluster. It allows you to separate sensitive data from the container images and provides a way to manage and distribute secrets separately from application code. Secrets can be used to configure environment variables, command-line arguments, or configuration files for Pods.
Q. What is a Kubernetes Persistent Volume, and what is its purpose?
A Kubernetes Persistent Volume is a storage resource that provides a way to store data beyond the lifetime of a Pod. It allows data to be stored independently of a Pod, making it easier to manage and preserve data between Pod restarts. Persistent Volumes can be dynamically provisioned or statically defined, and can be attached to one or more Pods. They provide a way to scale storage independently of compute resources.
Q. What is a Kubernetes StatefulSet, and how is it used?
A Kubernetes StatefulSet is an object that provides a way to manage stateful applications, such as databases, in a Kubernetes cluster. It ensures that each instance of the application is assigned a unique hostname and stable network identity, making it easier to manage stateful applications that require persistent storage and ordered deployment.
Q. What is a Kubernetes DaemonSet, and how is it used?
A Kubernetes DaemonSet is an object that ensures that a specific Pod is running on each node in a Kubernetes cluster. It is typically used to run daemon processes, such as log collectors or monitoring agents, on each node in the cluster. DaemonSets provide a way to manage node-level services across a cluster.
Q. What is a Kubernetes Operator, and how is it used?
A Kubernetes Operator is a way to extend Kubernetes by defining custom resources and controllers that automate application-specific tasks. Operators can automate complex application deployment and management tasks, such as scaling, backup and recovery, and failover. Operators provide a way to manage applications as code and enable developers to focus on building and iterating on applications rather than infrastructure.
Q. What is a Kubernetes Helm Chart, and how is it used?
A Kubernetes Helm Chart is a package of Kubernetes resources that can be deployed as a single unit. It provides a way to define, package, and deploy Kubernetes applications, making it easier to share and reuse application configurations. Helm Charts can be customized with values files, allowing you to deploy the same application with different configurations in different environments.
Q. What is Kubernetes' horizontal scaling, and how does it work?
Kubernetes' horizontal scaling is a way to increase the number of Pods running in a Kubernetes cluster to handle increased traffic or workload. Horizontal scaling is achieved through Kubernetes' built-in support for ReplicaSets, Deployments, and StatefulSets. Kubernetes automatically monitors resource usage and can scale up or down the number of Pods running based on specified criteria, such as CPU or memory usage. Horizontal scaling provides a way to handle increased traffic or workload without manual intervention, ensuring that applications are highly available and responsive.
Q. What is Kubernetes' vertical scaling, and how does it work?
Kubernetes' vertical scaling is a way to increase the resources allocated to a running Pod, such as CPU or memory. Vertical scaling is achieved through Kubernetes' support for resource limits and requests. Kubernetes can dynamically allocate more resources to a Pod if it exceeds its resource requests, ensuring that applications can handle increased workload without downtime.
Q. What is a Kubernetes Ingress, and how is it used?
A Kubernetes Ingress is an object that provides a way to expose HTTP and HTTPS routes from outside a Kubernetes cluster to services inside the cluster. Ingresses allow you to configure load balancing, SSL termination, and URL-based routing for services running in a Kubernetes cluster. Ingresses provide a way to manage external access to Kubernetes applications, allowing you to expose applications to the public or to specific groups of users.
Q. What is a Kubernetes Pod, and how is it used?
A Kubernetes Pod is the smallest unit of deployment in a Kubernetes cluster. It represents a single instance of a running process in a container. Pods can be managed by ReplicaSets, Deployments, or StatefulSets, and can share network and storage resources. Pods provide a way to encapsulate an application's runtime environment, making it easier to deploy and manage containerized applications.
Q. What is Kubernetes' Container Runtime Interface (CRI), and how is it used?
Kubernetes' Container Runtime Interface (CRI) is a plugin interface that provides a standard way to interact with container runtimes, such as Docker or CRI-O, in a Kubernetes cluster. CRI allows Kubernetes to support multiple container runtimes and provides a way to isolate and manage containers within Pods. CRI provides a way to abstract container runtimes, making it easier to manage and deploy containerized applications in a Kubernetes cluster.
Q. What is Kubernetes' API server, and how is it used?
Kubernetes' API server is the central component of a Kubernetes cluster. It provides a way to interact with and manage Kubernetes objects, such as Pods, Services, and Deployments, through a RESTful API. The API server provides a way to configure, deploy, and manage applications in a Kubernetes cluster, making it a critical component of the Kubernetes architecture.