Basic Architecture of Kubernetes

Introduction

• Kubernetes is a powerful but complex framework.
• Many users feel overwhelmed by its documentation.
• Kubernetes allows for management and orchestration of containers in a cluster.

Types of Nodes in Kubernetes

• Master Nodes
  • Control cluster state and manage worker nodes.
• Worker Nodes (Slave Nodes)
  • Run application pods with containers.

Components of Kubernetes Architecture

Worker Nodes

• Node Servers: Perform actual work.
• Application Pods: Contain containers running on nodes.
• Processes on Worker Nodes:
  1. Container Runtime
     • E.g., Docker, necessary for running containers.
  2. Kubelet
     • Schedules and starts pods with containers.
     • Ensures resources (CPU, RAM, Storage) are allocated.
  3. Kube Proxy
     • Acts as a load balancer, forwards requests to the correct pod.
     • Uses intelligent forwarding to minimize network overhead.

Master Nodes

• API Server
  • Gateway for user requests (via UI or command-line tools).
  • Handles authentication and authorization.
• Scheduler
  • Decides which worker node will run new pods based on resource availability.
• Controller Manager
  • Detects state changes (e.g., pod failures).
  • Reschedules or restarts pods using the scheduler and kubelet.
• etcd
  • Key-value store for cluster state information.
  • Central to all operations among master processes.

Cluster Setup and Management

• Multiple Nodes: Clusters can have numerous worker nodes.
• Adding Nodes:
  • New master or worker nodes can be easily added.
  • Install necessary processes and add to cluster.
• Resource Management:
  • Master nodes require fewer resources compared to worker nodes.
  • Worker nodes need more CPU, RAM, and storage.

Summary

• Master processes are critical for operations.
• Clusters usually have multiple master nodes for reliability.
• Kubernetes allows scalable cluster expansion.

Conclusion

• The video is part of a series, with new videos released weekly.
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