I have made a humble and simple effort to explain virtual machines, container concepts, and the basic cluster architecture of Kubernetes. StorageClasses are not unlike labels; operators use them to describe different types of storage, so that storage can be dynamically be provisioned based on incoming claims from pods. With many services, it can also become very complex. So, that’s the Kubernetes architecture in a simple fashion. A Kubernetes cluster sizing strategy that aims to maximize node count will not always deliver the best results – certainly not from a cost perspective, and perhaps not from an overall availability or performance perspective, either. Keep reading for an overview – if not a precise recommendation on how large your cluster should be, because only you can decide that for yourself. If the node is valid – that is, if all necessary services are running – it is eligible to run a pod. This logical construct packages up a single application, which can consist of multiple containers and storage volumes. Kubernetes Security: Architecture & Best Practices, Kubernetes in the Enterprise – Chapter 7: What You Need to Know About Platform9 Managed Kubernetes, Kubernetes in the Enterprise: Top Use Cases, Kubernetes in the Enterprise – Chapter 5: Managed Kubernetes Solutions, Detailed overview of the chief architectural concepts. In this module you’ll learn the components of a Kubernetes cluster and how they work together. ... [Low 00:04:18] in his video on Kubernetes concepts and control loops. Kubernetes (also known as k8s) is a platform for automating deployment, scaling, and management of containerized applications. When it comes to Kubernetes clusters, size matters. Kubernetes is notoriously difficult to deploy and operate at scale — particularly for enterprises managing both on-premises and public cloud infrastructure. The space has become crowded, and difficult for organizations to navigate and compare the various offerings. Moving on, lets see ETCD. Twitter: @edXOnline. These dynamic assignments make releasing new versions or adding pods to a service really easy. At its core, a volume is just a directory, possibly with some data in it, which is accessible to a pod. Pods are one of the crucial concepts in Kubernetes, as they are the key construct that developers interact with. Instead, calculating the number of nodes to include in a cluster requires careful consideration of a variety of factors. Marcus covers: - Key Kubernetes architectures - … Lower-level detail relevant to creating or administering a Kubernetes cluster. Jenkins X builds upon the following core components: Kubernetes & Docker True, if the commit passes the various tests in the Integration phase; false, if it does not. When you create an AKS cluster, a control plane is automatically created and configured. Architecture & Concepts Pulumi is a modern infrastructure as code platform. It provides a container runtime, container orchestration, container-centric infrastructure orchestration, self-healing mechanisms, service discovery and load balancing. Thanks for the feedback. Architecture. The cloud controller manager (CCM) concept (not to be confused with the binary) was originally created to allow cloud specific vendor code and the Kubernetes core to evolve independent of one another. A Kubernetes cluster is divided into two components: Control plane nodes provide the core Kubernetes services and orchestration of application workloads. Kubernetes cluster architecture. Selectors use labels to filter or select objects, and are used throughout Kubernetes. There is also a lot that it doesn’t do. If you are running more containers or want automated management of your containers, you need Kubernetes at your disposal. Policies you can configure that apply to groups of resources. From a high level, a Kubernetes environment consists of a control plane (master), a distributed storage system for keeping the cluster state consistent (etcd), and a number of cluster nodes (Kubelets). Kubernetes is a very flexible and extensible platform. K8s Architecture. You'll deploy a Kubernetes cluster using Google Kubernetes Engine and deploy Pods to a GKE cluster. It could be thought of as the operating system for cloud-native applications in the sense that it’s the platform that applications run on, just as desktop applications run on MacOS, Windows, or Linux. There are many different Ingress controllers (Nginx, Ambassador), and there’s support for cloud-native load balancers (from Google, Amazon, and Microsoft). report a problem If you have a specific, answerable question about how to use Kubernetes, ask it on Try the Course for Free. Contino Consultant Marcus Maxwell takes you through a high-level overview of Kubernetes - a leading open-source container orchestration tool. This type of dynamic storage allocation is commonly used where storage is a service, as in public cloud providers or storage systems like CEPH. Kubernetes Architecture Core Concepts – Now, somebody needs to load, control and manage the containers therefore there are control or master nodes in the cluster. Stack Overflow. Pods are one of the crucial concepts in Kubernetes, as they are the key construct that developers interact with. The need for proper resource planning is amplified within a Kubernetes cluster, as it does hard checks and will kill and move workloads around without hesitation and based on nothing but current resource usage. Here are the basic tools you should know: There’s also a graphical dashboard, Kube Dashboard, which runs as a pod on the cluster itself. Labels distinguish resources within a single namespace. If you’re ready to get started, you can deploy a free Kubernetes cluster on AWS or on-premises under five minutes: https://platform9.com/signup/. Custom Resources. Read more: Kubernetes Cluster Sizing – How Large Should a Kubernetes Cluster Be? suggest an improvement. The Scheduler is responsible for the scheduling of containers across the nodes in the cluster; it takes various constraints into account, such as resource limitations or guarantees, and affinity and anti-affinity specifications. As the above illustration shows, the control plane is made up of three major components: kube-apiserver, kube-controller-manager and kube-scheduler. The control plane is the system that maintains a record of all Kubernetes objects. The number of nodes in your cluster plays an important role in determining the overall availability and performance of your workloads. To secure Kubernetes effectively for real-world deployment, you must understand which built-in security features Kubernetes offers and which it doesn’t, and how to leverage Kubernetes’s security capabilities at scale. It also acts as the gateway to the cluster, so the API server must be accessible by clients from outside the cluster. This means containers can communicate over localhost. To learn more about Kubernetes in the Enterprise, download the complete guide now. They’re cluster-wide objects linked to the backing storage provider that make these resources available for consumption. Kubernetes provides no native storage solution for log data, but you can integrate many existing logging solutions into your Kubernetes cluster. or When it comes to security, there is a lot that Kubernetes does. A pod represents a running process on a cluster. In most cases, the Container Network Interface (CNI) uses a simple overlay network (like Flannel) to obscure the underlying network from the pod by using traffic encapsulation (like VXLAN); it can also use a fully-routed solution like Calico. That is, we deploy a unique instance of a CI/CD container that will monitor a code version control system, so whenever we push to that repository, the container will run pipeline steps. Discovering services is a crucial part of a healthy Kubernetes environment, and Kubernetes heavily relies on its integrated DNS service (either Kube-DNS or CoreDNS, depending on the cluster version) to do this. Kubernetes uses the concept of volumes. Kubernetes Concepts. References: Kubernetes Components By default, services are only reachable inside the cluster using the clusterIP service type. Kubern e tes defines a set of building blocks (“primitives”), which collectively provide mechanisms that deploy, maintain, and scale applications based on CPU, memory or custom metrics. Finally, StorageClasses are an abstraction layer to differentiate the quality of underlying storage. There are many options for mounting both file and block storage to a pod. Kubernetes Cluster Sizing – How Large Should a Kubernetes Cluster Be? It allows developers to build customized workflows and higher-level automation to deploy and manage applications composed of multiple containers. It includes a CLI, runtime, libraries, and a hosted service that, working together, deliver a robust way of provisioning, updating, and managing cloud infrastructure. The design document explains how the Kubernetes Ingress Controller works inside a Kubernetes cluster and configures Kong to proxy traffic as per rules defined in the Ingress resources.. It continuously manages object states, responding to changes in the cluster; it also works to make the actual state of system objects match the desired state. Kubernetes follows a client-server architecture, it’s possible to have a multi-master setup, by default there is a single master server which acts as a controlling all nodes. one of the main use cases of Kubernetes is to run Continuous Integration or Continuous Delivery (CI/CD) pipelines. ... Kubernetes Concepts 4:48. It will spin up a load balancer per service on the cloud environment, which can be expensive. Pods can do horizontal autoscaling (i.e., grow or shrink the number of instances), and perform rolling updates and canary deployments. Chief Strategist at Platform9 Systems. Networking Kubernetes has a distinctive networking model for cluster-wide, podto-pod networking. Storage in a pod can be consumed by any containers in the pod. Within a pod, containers can communicate without any restrictions. Cluster nodes are machines that run containers and are managed by the master nodes. In Kubernetes, scheduling refers to making sure that Pods are matched to Nodes so that the kubelet can run them. They are key/value pairs that describe attributes, and can be used to organize and select subsets of objects. An example of a DNS record for a Kubernetes service: Namespaces are virtual clusters within a physical cluster. This prevents objects from being hard linked. K8s : technology developed in Google lab in 2005 to manage containerized applications in different kind of environments such as physical, virtual, and cloud infrastructure. The applications can vary in sizes: from hundreds to thousands of nodes. It aims to reduce the burden of orchestrating underlying compute, network, and storage infrastructure, and enable application operators and developers to focus entirely on container-centric workflows for self-service operation. This article includes recommendations for networking, security, identity, management, and monitoring of the cluster based on an organization’s business requirements. Architecture The design document explains how Kong Ingress Controller works inside a Kubernetes cluster and configures Kong to proxy traffic as per rules defined in the Ingress resources. Pods are ephemeral, with a limited lifespan. Access Clusters Using the Kubernetes API (EN) Access Services Running on Clusters (EN) Advertise Extended Resources for a Node (EN) Autoscale the DNS Service in a Cluster (EN) Change the default StorageClass (EN) Change the Reclaim Policy of a PersistentVolume (EN) Cloud Controller Manager Administration (EN) Configure Out of Resource Handling (EN) Configure Quotas for API Objects (EN) Control CPU Management Policies on the Node (EN) Control Topology Management Policies on a node …