Day 5 Guide: Exploring Kubernetes Architecture in the 40-Day Kubernetes Challenge
Kubernetes is a powerful open-source platform for managing containerized applications. It provides a way to deploy, scale, and manage applications across multiple clusters of computers.
In this blog post, we will explain the architecture of Kubernetes. We will also discuss the different components of Kubernetes and how they work together.
Kubernetes Architecture
The Kubernetes architecture consists of two main components: the control plane and the worker nodes.
The control plane is a set of processes that run on one or more machines. It is responsible for managing the Kubernetes cluster. The control plane includes components such as the API server, the scheduler, the controller manager, and etcd.
The worker nodes are machines that run your applications. They are also known as minions or agents. Worker nodes run a set of processes that communicate with the control plane. These processes include the kubelet, the kube-proxy, and the container runtime.
The flow of the diagram is as follows:
The user types a Kubectl command in the terminal.
The Kubectl client sends the command to the Kubernetes API server.
The Kubernetes API server processes the command and sends it to the appropriate component.
The component completes the task and sends the results back to the Kubernetes API server.
The Kubernetes API server sends the results back to the Kubectl client.
The Kubectl client displays the results to the user.
Kubernetes Components
API Server: The API server is the front door to the Kubernetes cluster. It is responsible for receiving and processing requests from clients.
Scheduler: The scheduler is responsible for assigning pods to worker nodes. It considers factors such as resource availability and affinity rules when making its decisions.
Controller Manager: The controller manager is a set of controllers that are responsible for managing different Kubernetes resources. For example, the replication controller is responsible for ensuring that a desired number of pods are running for a given application.
etcd: etcd is a distributed key-value store that is used to store the state of the Kubernetes cluster.
Kubelet: The kubelet is a process that runs on each worker node. It is responsible for communicating with the control plane and managing pods on the node.
Kube-proxy: The kube-proxy is a process that runs on each worker node. It is responsible for managing the network for the pods on the node.
Container Runtime: The container runtime is a process that is responsible for running containers on the worker nodes. There are several different container runtimes that can be used with Kubernetes, such as Docker and containerd.
How Kubernetes Works
When you create a Kubernetes resource, such as a deployment, the API server receives the request and stores it in etcd. The scheduler then assigns the deployment to a worker node. The kubelet on the worker node creates the pods specified in the deployment. The kube-proxy configures the network for the pods. The container runtime starts the containers in the pods.
Conclusion
Kubernetes is a powerful platform for managing containerized applications. By understanding the architecture of Kubernetes, you can better understand how it works and how to use it effectively.
References
Video:
https://www.youtube.com/watch?v=SGGkUCctL4I&list=PLl4APkPHzsUUOkOv3i62UidrLmSB8DcGC&index=6
Documentation: