Containerization (Docker, Kubernetes) Questions and Answers for Viva

Answer-1: Containerization is a lightweight virtualization method that packages an application and its dependencies into a container, ensuring it runs consistently across different environments.

Answer-2: Docker is an open-source platform that automates the deployment, scaling, and management of containerized applications.

Answer-3: Containers share the host OS kernel and isolate applications, making them more lightweight and faster to start than virtual machines which include a full OS.

Answer-4: A Docker image is a read-only template with instructions for creating a Docker container.

Answer-5: A Docker container is a runtime instance of a Docker image, including the application and its dependencies.

Answer-6: By running the command `docker run` with a specified Docker image.

Answer-7: A Dockerfile is a text file that contains instructions to build a Docker image.

Answer-8: Docker Hub is a cloud-based repository where Docker images can be stored and shared.

Answer-9: By using Docker volumes or bind mounts to store data outside the container filesystem.

Answer-10: Kubernetes is an open-source container orchestration platform for automating deployment, scaling, and management of containerized applications.

Answer-11: A pod is the smallest deployable unit in Kubernetes, which can contain one or more containers sharing storage, network, and specification.

Answer-12: Docker focuses on containerization, while Kubernetes orchestrates and manages multiple containers across clusters.

Answer-13: Main components include the Master Node (API Server, Scheduler, Controller Manager), Worker Nodes, kubelet, and etcd.

Answer-14: A Kubernetes cluster is a set of nodes that run containerized applications managed by Kubernetes.

Answer-15: It acts as the front end for the Kubernetes control plane, handling REST requests and updates.

Answer-16: A Deployment manages stateless applications, ensuring the desired number of pod replicas are running.

Answer-17: A StatefulSet manages stateful applications, providing stable network IDs and persistent storage.

Answer-18: A Service defines a logical set of pods and a policy to access them, often via load balancing.

Answer-19: ReplicaSet ensures a specified number of pod replicas, while Deployment provides declarative updates and rollback capabilities.

Answer-20: By adjusting the number of replicas in a Deployment using commands like `kubectl scale` or autoscaling.

Answer-21: Namespaces provide a way to divide cluster resources between multiple users or teams.

Answer-22: Helm is a package manager for Kubernetes that simplifies deployment and management of applications.

Answer-23: A container registry is a storage and distribution system for container images, such as Docker Hub or Google Container Registry.

Answer-24: Docker networking allows containers to communicate via network drivers like bridge, host, or overlay networks.

Answer-25: Docker volumes provide persistent storage that is independent of the container lifecycle.

Answer-26: Kubernetes automatically restarts failed containers and reschedules pods on healthy nodes.

Answer-27: kubelet runs on each worker node and manages pod lifecycle according to the Kubernetes API.

Answer-28: Ingress manages external access to services in a cluster, typically HTTP, providing load balancing and SSL termination.

Answer-29: Docker Compose is used for defining and running multi-container Docker applications on a single host, Kubernetes manages containerized applications at scale across clusters.

Answer-30: A sidecar container runs alongside the main container in a pod to extend functionality, such as logging or monitoring.

Answer-31: Using `kubectl apply` to update Deployment manifests, which triggers rolling updates.

Answer-32: etcd is a distributed key-value store used to store cluster state and configuration data.

Answer-33: Container orchestration automates deployment, management, scaling, and networking of containers.

Answer-34: Docker Swarm is Docker?s native clustering tool with simpler setup, Kubernetes is more feature-rich and widely adopted for production environments.

Answer-35: By replicating pods, automatic rescheduling on healthy nodes, and multi-master configurations.

Answer-36: A DaemonSet ensures that a copy of a pod runs on all or selected nodes.

Answer-37: Using tools like Prometheus, Grafana, ELK stack, or Kubernetes-native monitoring solutions.

Answer-38: Labels are key-value pairs attached to objects, and selectors are queries to filter objects based on labels.

Answer-39: Kubernetes Secrets store sensitive information like passwords and tokens securely.

Answer-40: ConfigMap stores non-confidential configuration data in key-value pairs for pods.

Answer-41: Using NodePort, LoadBalancer, or Ingress resources.

Answer-42: Rolling update updates pods gradually without downtime; recreate stops old pods before starting new ones.

Answer-43: Container images are built in layers, each representing a filesystem change, enabling reuse and efficient storage.

Answer-44: By implementing container isolation, role-based access control (RBAC), network policies, and secrets management.

Answer-45: The Docker daemon runs in the background to build, run, and manage containers.

Answer-46: Using Persistent Volumes (PV) and Persistent Volume Claims (PVC) to manage storage independent of pod lifecycle.

Answer-47: An Operator extends Kubernetes functionality to manage custom resources and automate application lifecycle management.

Answer-48: Namespaces isolate resources and access for multi-tenant clusters.

Answer-49: Using `kubectl logs`, `kubectl describe pod`, and events inspection to identify issues.

Answer-50: Containers are immutable once built, meaning changes require building and deploying a new image to ensure consistency.