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Certified Kubernetes Administrator (CKA) Exam Guide

You're reading from   Certified Kubernetes Administrator (CKA) Exam Guide Validate your knowledge of Kubernetes and implement it in a real-life production environment

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Product type Paperback
Published in Nov 2022
Publisher Packt
ISBN-13 9781803238265
Length 322 pages
Edition 1st Edition
Concepts
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Author (1):
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Mélony Qin Mélony Qin
Author Profile Icon Mélony Qin
Mélony Qin
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Table of Contents (17) Chapters Close

Preface 1. Part 1: Cluster Architecture, Installation, and Configuration
2. Chapter 1: Kubernetes Overview FREE CHAPTER 3. Chapter 2: Installing and Configuring Kubernetes Clusters 4. Chapter 3: Maintaining Kubernetes Clusters 5. Part 2: Managing Kubernetes
6. Chapter 4: Application Scheduling and Lifecycle Management 7. Chapter 5: Demystifying Kubernetes Storage 8. Chapter 6: Securing Kubernetes 9. Chapter 7: Demystifying Kubernetes Networking 10. Part 3: Troubleshooting
11. Chapter 8: Monitoring and Logging Kubernetes Clusters and Applications 12. Chapter 9: Troubleshooting Cluster Components and Applications 13. Chapter 10: Troubleshooting Security and Networking 14. Index 15. Other Books You May Enjoy Appendix - Mock CKA scenario-based practice test resolutions

Troubleshooting networking

In Chapter 7, Demystifying Kubernetes Networking, we learned that the Kubernetes DNS server creates DNS records (A/AAAA, SRV, and PTR records) for services and pods in Kubernetes. Those efforts allow you to contact Services with consistent DNS names in place of the IP addresses. The Kubernetes DNS server does this by scheduling a few copies of DNS pods and services on the Kubernetes cluster.

In the following section, let’s talk about how to troubleshoot the Kubernetes DNS service.

Troubleshooting a Kubernetes DNS server

To troubleshoot the networking of Kubernetes, we start by checking the status of the DNS server. Using minikube as a local cluster this time, we use the following command to check whether the DNS server is up and running on your cluster:

kubectl get pods -n kube-system | grep dns

The output should be similar to the following:

coredns-64897985d-brqfl 1/1 Running 1 (2d ago) 2d

From the preceding output, we can...

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