Book Image

Mastering Kubernetes

By : Gigi Sayfan
Book Image

Mastering Kubernetes

By: Gigi Sayfan

Overview of this book

Kubernetes is an open source system to automate the deployment, scaling, and management of containerized applications. If you are running more than just a few containers or want automated management of your containers, you need Kubernetes. This book mainly focuses on the advanced management of Kubernetes clusters. It covers problems that arise when you start using container orchestration in production. We start by giving you an overview of the guiding principles in Kubernetes design and show you the best practises in the fields of security, high availability, and cluster federation. You will discover how to run complex stateful microservices on Kubernetes including advanced features as horizontal pod autoscaling, rolling updates, resource quotas, and persistent storage back ends. Using real-world use cases, we explain the options for network configuration and provides guidelines on how to set up, operate, and troubleshoot various Kubernetes networking plugins. Finally, we cover custom resource development and utilization in automation and maintenance workflows. By the end of this book, you’ll know everything you need to know to go from intermediate to advanced level.
Table of Contents (22 chapters)
Mastering Kubernetes
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
Index

Detecting node problems


In Kubernetes' conceptual model the unit of work is the pod. But, pods are scheduled on nodes. When it comes to monitoring and reliability, the nodes are what require the most attention because Kubernetes itself (the scheduler and replication controllers) takes care of the pods. Nodes can suffer from a variety of problems that Kubernetes is unaware of. As a result, it will keep scheduling pods to the bad nodes and the pods might fail to function properly. Here are some of the problems that nodes may suffer while still appearing functional:

  • Bad CPU

  • Bad memory

  • Bad disk

  • Kernel deadlock

  • Corrupt filesystem

  • Problems with the Docker Daemon

The kubelet and cAdvisor don't detect these issues. Another solution is needed. Enter the node problem detector.

Node problem detector

The node problem detector is a pod that runs on every node. It needs to solve a difficult problem. It needs to detect various problems across different environments, different hardware, and different OSes. It needs...