1. What is Kubernetes and Why is it Important?
Kubernetes is an open-source platform designed to automate the deployment, scaling, and operation of application containers.
It’s important because it simplifies the management of containerized applications, ensuring high availability, scalability, and operational efficiency.
2. Difference Between Docker Swarm and Kubernetes
Docker Swarm is a native clustering and scheduling tool for Docker containers, emphasizing simplicity and ease of use.
Kubernetes offers a robust ecosystem with extensive features for managing containerized applications, including advanced scheduling, self-healing, and scaling.
3. How Kubernetes Handles Network Communication Between Containers
Kubernetes uses a flat networking model where each Pod is assigned a unique IP address. This allows containers within a Pod to communicate freely, while services manage communication between different Pods using cluster IPs and DNS.
4. How Kubernetes Handles Scaling of Applications
Kubernetes scales applications by adjusting the number of Pod replicas. This can be done manually or automatically based on CPU usage, memory usage, or custom metrics through the Horizontal Pod Autoscaler.
5. What is a Kubernetes Deployment and How Does it Differ from a ReplicaSet?
A Deployment in Kubernetes manages ReplicaSets and provides declarative updates to applications.
A ReplicaSet ensures a specified number of pod replicas are running at any given time. Deployments offer additional features like rolling updates and rollbacks.
6. Rolling Updates in Kubernetes
Rolling updates allow you to update applications without downtime. Kubernetes gradually replaces old versions of pods with new ones, ensuring at least a portion of the application remains available during the update process.
7. Network Security and Access Control in Kubernetes
Kubernetes handles network security through Network Policies, which define how pods can communicate with each other and with external services. Access control is managed using Role-Based Access Control (RBAC), limiting user and application permissions within the cluster.
8. Deploying a Highly Available Application in Kubernetes
To deploy a highly available application, you can use Deployments with multiple replicas spread across different nodes. Services ensure traffic is distributed evenly among the pods, while persistent storage options like StatefulSets manage data consistency.
9. Namespace in Kubernetes
A namespace in Kubernetes is a way to divide cluster resources between multiple users. If no namespace is specified, the default namespace is used. Namespaces provide a mechanism to isolate groups of resources within the same cluster.
10. How Ingress Helps in Kubernetes
Ingress manages external access to services within a Kubernetes cluster, typically HTTP and HTTPS. It allows you to define rules for routing traffic to different services, enabling load balancing, SSL termination, and name-based virtual hosting.
11. Different Types of Services in Kubernetes
ClusterIP: Exposes the service on an internal IP within the cluster.
NodePort: Exposes the service on each node's IP at a static port.
LoadBalancer: Exposes the service externally using a cloud provider’s load balancer.
ExternalName: Maps a service to a DNS name.
12. Self-Healing in Kubernetes
Kubernetes ensures self-healing by automatically restarting failed containers, rescheduling pods on healthy nodes, and replacing or killing containers that don’t respond to user-defined health checks.
13. Storage Management in Kubernetes
Kubernetes uses Persistent Volumes (PVs) and Persistent Volume Claims (PVCs) for storage management. PVs are storage resources in the cluster, while PVCs are requests for those resources. Storage Classes allow dynamic provisioning of storage.
14. NodePort Service in Kubernetes
A NodePort service exposes a service on a static port on each node’s IP address. This makes the service accessible externally by requesting <NodeIP>:<NodePort>
.
15. Multinode Cluster vs. Single-Node Cluster in Kubernetes
Single-Node Cluster: All control plane and worker node components run on one machine, ideal for development or testing.
Multinode Cluster: Separates control plane components and runs them on multiple machines for high availability and fault tolerance, used in production environments.
16. Difference Between create
and apply
in Kubernetes
create: Creates a resource from a file or standard input, but does not update existing resources.
apply: Creates and updates resources in a declarative way by managing the entire configuration of the resource.
Kubernetes provides a powerful framework for managing containerized applications, ensuring they run efficiently and reliably in diverse environments. Its extensive feature set and robust ecosystem make it a critical tool in modern DevOps and cloud-native application management.