Architecture of Kubernetes(Master Node)

Components of Master Node

1. API Server :
   API server is supposed to be the front face that communicates with nodes and the other components of the control plane. Every node provides its requirements to the API server (i.e. Manifest file) which are then forwarded by API server to Controller Manager.

2. Controller Manager :
   Controller Manager checks if all the requirements that are asked by the slave node are getting fulfilled or not i.e. if the actual state is equivalent to desired state or not. It's responsible to maintain balance b/w the two states.
   Here comes the role of the etcd cluster.

3. etcd Cluster :
   If K8s is on cloud, then Cloud-Control Manager will be in role and if K8s is on premises, then Kube-Control Manager is found in action.
   Etcd is responsible for storing metadata and status of a cluster in key-value pair format.
   It's consistent and is highly available.
   Source of truth for cluster i.e. you can find all the information of cluster with etcd.

4. Scheduler :
   Kube scheduler responds to those requests which are generated by the user for creation and management of POD.
   If the manifest user has not mentioned the node on which it wants POD to be created, in that case, Kube Scheduler finds the best Salve node on which POD can be created and then creates the POD on that node.
   It gets information for hardware configuration from configuration files and schedules the POD’s on the slave nodes accordingly.

Architecture Diagram of Kubernetes
(https://dev-to-uploads.s3.amazonaws.com/uploads/articles/frqk1mrp4d81dyn41v2h.png)