Thread by @SignozHQ

A Kubernetes cluster is made of control plane nodes and worker nodes. And the nodes are made up of a number of components with specific functionalities 🌊

Thread 🧵👇🏻

#kubernetes #devops #docker

🧠 Control plane or the master node
These nodes handle and manage the Kubernetes cluster. They don’t run any containers. The main components of a control plane node 👇
👉 API Server
👉 Scheduler
👉 Controller-manager
👉 Storage or etcd

Let’s explain these components one by one.

💠 API Server

It is the only entry point to a Kubernetes cluster that you directly interact with. User commands are sent to the API server, and we receive responses from the API server.

💠 Scheduler

The scheduler chooses which nodes(can be physical servers, VMs, cloud instances, anything) to run the user application on.

💠 Controller-manager

Allows Kubernetes to integrate with cloud services, such as storage and load-balancers.

💠 Storage or etcd
It’s where the state of the cluster and all the applications are stored. Kubernetes uses etcd as its database. Because Kubernetes is a distributed system, it needs a distributed database like etcd.

You can learn more about etcd here 👇

etcd.io

🧑‍💻 Worker nodes

Worker nodes or just nodes are where user applications run. The main components of worker nodes 👇

👉 Kubelet

👉 Kube-proxy

👉 Container Runtime

Let’s explain these components one by one.

💠 Kubelet

An agent that runs on each worker node of the cluster. It communicates with the control plane reporting on the status of containers and tasks.

💠 Kube-proxy

Responsible for local cluster networking. It ensures each node gets its own unique IP address and implements rules to handle routing and load-balancing of traffic.

💠 Container Runtime

Container runtime is the software for running containers.

That’s all for this thread on components of Kubernetes nodes 🧡

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