Book Image

Kubernetes – An Enterprise Guide - Second Edition

By : Marc Boorshtein, Scott Surovich
Book Image

Kubernetes – An Enterprise Guide - Second Edition

By: Marc Boorshtein, Scott Surovich

Overview of this book

Kubernetes has taken the world by storm, becoming the standard infrastructure for DevOps teams to develop, test, and run applications. With significant updates in each chapter, this revised edition will help you acquire the knowledge and tools required to integrate Kubernetes clusters in an enterprise environment. The book introduces you to Docker and Kubernetes fundamentals, including a review of basic Kubernetes objects. You’ll get to grips with containerization and understand its core functionalities such as creating ephemeral multinode clusters using KinD. The book has replaced PodSecurityPolicies (PSP) with OPA/Gatekeeper for PSP-like enforcement. You’ll integrate your container into a cloud platform and tools including MetalLB, externalDNS, OpenID connect (OIDC), Open Policy Agent (OPA), Falco, and Velero. After learning to deploy your core cluster, you’ll learn how to deploy Istio and how to deploy both monolithic applications and microservices into your service mesh. Finally, you will discover how to deploy an entire GitOps platform to Kubernetes using continuous integration and continuous delivery (CI/CD).
Table of Contents (17 chapters)
15
Other Books You May Enjoy
16
Index

Understanding the worker node components

Worker nodes, as the name implies, are responsible for running workloads. When we discussed the kube-scheduler component of the control plane, we mentioned that when a new Pod is scheduled, the kube-scheduler component will decide which node to run the Pod on. It does this using information that has been sent to it from the worker nodes. This information is constantly updated to help spread Pods around a cluster to utilize resources efficiently.

Each worker node has two main components, kubelet and kube-proxy:

kubelet

You may hear a worker node referred to as a kubelet. The kubelet is an agent that runs on all worker nodes, and it is responsible for running the actual containers.

kube-proxy

Contrary to the name, kube-proxy is not a proxy server at all. kube-proxy is actually responsible for routing network communication between a Pod and the network.

Container runtime

Each node also needs a container runtime. A container...