Do you have any pods that are waiting to go somewhere?” It will read that out and it’ll say, “Hey, yeah, like I’ve got three pods, maybe that need to be scheduled.” It’ll take things into account like taints and tolerations where the pods should be scheduled, availability zones maybe, and then it’ll write the name of a node into that pod and it will again write it back to etc. Here are the key components and how they fit into the picture. And all it’s really responsible for doing is programming iptables, in most cases. So, let’s see its components: Kubernetes architecture So it’s not actually telling a node to do anything at this point. Kubernetes is made up of a number of components across control and workload planes. But kube-proxy is the component that’s responsible for programming, and that’s why it has to run on every single node. You send the description of your application and its configuration to the API on the master node through the `kubectl` command line utility. Nodes. Send your thoughts to KubeAcademy@VMware.com. Kubernetes is a robust yet complex infrastructure system for container orchestration, with multiple components that must be adequately protected. Post your questions in the Kubernetes community Slack. Kubernetes (also known as k8s) is a platform for automating deployment, scaling, and management of containerized applications. Not yet a part of the Kubernetes Slack community? The Kube-api-server is an API use by every components of the master components. ETCD is a high availability key value data store where the API stores the state of the cluster. And you can have any number of those connected to your cluster within reason. How to share a filesystem on AWS EKS with EBS volumes? It oversees nodes leaving and joining the cluster and ensures the current state of the cluster is always in check with the desired state stored in ETCD. It does reads from etcd and does writes from etcd. Questions about this lesson are best suited for the #kubernetes-users channel. So you can kind of think of the kubelet a little bit as a control loop as well. Kubernetes has a flexible architecture which provides for a loosely-coupled mechanism for service discovery. It’ll then do authorization. Cloud Controller Manager. We want to hear it! Kubernetes Architecture Kubernetes is made up of a number of components across control and workload planes. It’ll then do serialization of that request, so our deployments, going to serialize it into a particular format and then it’s going to write that to etcd. And that’s really just a fancy way of saying it keeps all the data in sync between the three nodes. In order to get a deeper understanding, you are highly encouraged to deploy each of the components separately and setup their communication from scratch. It also does a little bit of validation on your resources that you deploy to it, so kubectl or client-side libraries also do client-side validation to make sure they’re not just sending garbage to the API server, but the server does a little bit of validation, too. A Kubernetes cluster has one or more control planes, and one or more compute nodes. The master server consists of various… Thanks for joining us and we hope to see you in another video. They could run collocated with a control plane in what we call a stacked configuration, but we like to run them separately because they have a slightly different backup, restore, and performance profile. Kubelet acts as a component within the worker architecture accountable for the node level management of pods. But then there’s authentication to make sure we are who we say we are using one of the various authentication methods. It functions based on a declarative model and implements the concept of a ‘ desired state.’ These steps illustrate the basic Kubernetes process: Kubernetes Control Plane is responsible for managing the life-cycle of the pods and handle all of the details. So this is where the scheduler comes in. So the API server is stateless. Okay, so now we’ve written our replica set, we’ve written our pod information back into etcd. It also ensures that every container is working healthily. However, it wouldn’t be possible to manage all these pods manually; that is where the Kubernetes Control Plane has a role to play. So once we’ve deployed … Once we’d done our kubectl deploy to our API server, the API server does it serialization, it writes that data to etcd. Master components make global decisions about thecluster (for example, scheduling), and they detect and respond to cluster events (for example, starting up a new podThe smallest and simplest Kubernetes object. Advancing to the next lesson in 5 seconds…. So it’s important to note that the API server is the only thing that talks to etcd. Like I said, these usually run on three separate nodes to the control plane. What are Kubernetes Clusters vs. We deployed a mini-kubernetes setup inside a docker container, and deployed our fist pod. It’s just changing information then writing things back into etc. The applications can vary in sizes: from hundreds to thousands of nodes. It yields pods virtual network interfaces and local IP addresses. And this is the main entry point to the cluster. My name is John and I'm a Senior Cloud Native Architect @ VMware where I work with customers to help design and implement Kubernetes solutions, in addition to contributing back to upstream open source projects. The Kubernetes DNS Service allow pods to communicate with each other using their name or FQDN (Fully Qualified Domain Name) instead of their local IP. 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