ROAD TO CKA [Certified Kubernetes Administrator ]-Core Concept- Control Plane/Master Node (Day-5)
Tags: devops, kubernetes, cka, roadtocka
Published: 2023-07-12 13:15:40

Welcome to my Blog "Road To CKA" Day-5 . I am prepraing myself for the Certified Kubernetes Administrator and i wolud like to share my journey with you all. To preprar myself for the CKA Exam i am following:

- Roadmap from [Roadmap.sh](https://roadmap.sh/kubernetes)

- [Kubernetes Documentation](https://kubernetes.io/docs/home/)

- Udemy course - [Certified Kubernetes Administrator (CKA) with Practice Tests](https://www.udemy.com/course/certified-kubernetes-administrator-with-practice-tests/) created By Mumshad Mannambeth

-Coursera - [IBM DevOps and Software Engineering Professional Certificate ](https://www.coursera.org/professional-certificates/devops-and-software-engineering) created By IBM . 

I will try my best to share with you my daily learing topics and describe the theam in my own way.

[ROAD TO CKA [Certified Kubernetes Administrator ]-Prepration Resources (Day-1)](https://dev.to/capriciousbased/road-to-cka-day-1-5b0p)

[ROAD TO CKA [Certified Kubernetes Administrator ]-Exam Prerequisites,Syllabus , Exam details(Day-2)](https://dev.to/capriciousbased/road-to-cka-certified-kubernetes-administrator-exam-prerequisitessyllabus-exam-detailsday-2-46e4)

[ROAD TO CKA [Certified Kubernetes Administrator ]-What Kubernetes is & is not?(Day-3)](https://dev.to/capriciousbased/road-to-cka-certified-kubernetes-administrator-what-kubernetes-is-is-notday-3-1bo2)

[ROAD TO CKA [Certified Kubernetes Administrator ]-Kubernetes Architecture(Day-4)](https://dev.to/capriciousbased/road-to-cka-certified-kubernetes-administrator-kubernetes-architectureday-4-2n01)


Today i would like to share information about Kubernetes Core Concept specially Control Plane or Master Node . 

A Kubernetes cluster generally consists of two classes of nodes:

- Control plane Node(Master Node)

- Worker Node

Control plane node(Master Node): The master node is the first and most vital component which is responsible for the management of Kubernetes cluster. It is the entry point for all kinds of administrative tasks. There may be more than one master node in the cluster to check for fault tolerance.

![kubentes cluster image](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/3elsjbp078i7jj6wj733.png)
Kubernetes cluster image from kubernetes documentation page

The master node has various components, each having its process. They are:

- ETCD
- Controller Manager
- Scheduler
- API Server

The master node typically consists of several components that perform specific functions:

**API Server:** The API server serves as the front-end for the Kubernetes control plane. It exposes the Kubernetes API, which allows users and other components to interact with the cluster. It processes and validates API requests, then updates the cluster state accordingly.

**Scheduler:** The scheduler is responsible for assigning pods (the smallest deployable units in Kubernetes) to worker nodes based on resource availability, placement constraints, and other policies. It ensures efficient utilization of resources and optimal distribution of workloads across the cluster.
**Controller Manager:** The controller manager runs various controllers that are responsible for managing different aspects of the cluster's behavior. For example, there are controllers for handling replication, managing endpoints, monitoring node health, and performing other crucial tasks.

**etcd:** etcd is a distributed key-value store that serves as the cluster's reliable data store. It stores the configuration data and the current state of the cluster, allowing the control plane components to read and update this information as needed.

Why do we need a master node? Here are some reasons:

**Cluster Management:** The master node provides centralized management and control of the entire cluster. It ensures that the cluster is in the desired state and handles tasks such as scaling, deploying applications, and maintaining high availability.

**Resource Allocation:** The master node makes intelligent decisions about resource allocation based on the cluster's policies and constraints. It decides which worker node should run which pods, taking into account factors like resource availability, workload affinity, and anti-affinity.

**Fault Tolerance:** The master node is designed to be highly available and resilient. It can handle failures and recover from them by automatically rescheduling tasks and maintaining the desired state of the cluster. It employs techniques like leader election and replication to ensure fault tolerance.

**Security and Authentication:** The master node enforces security measures and authentication mechanisms to control access to the cluster. It authenticates users, validates their requests, and applies the necessary authorization policies.

Overall, the master node plays a critical role in managing and orchestrating a Kubernetes cluster, providing the necessary control and coordination for efficient and reliable operation.

If you would like to read more please habe a look here in Kubernetes [Documentation](https://kubernetes.io/docs/concepts/overview/components/) . 

Tomorrow i will try to give some information about Worker Node.                   

                               [To Be Continued....]