Book Image

Certified Kubernetes Administrator (CKA) Exam Guide

By : Mélony Qin
4 (1)
Book Image

Certified Kubernetes Administrator (CKA) Exam Guide

4 (1)
By: Mélony Qin

Overview of this book

Kubernetes is the most popular container orchestration tool in the industry. The Kubernetes Administrator certification will help you establish your credibility and enable you to efficiently support the business growth of individual organizations with the help of this open source platform. The book begins by introducing you to Kubernetes architecture and the core concepts of Kubernetes. You'll then get to grips with the main Kubernetes API primitives, before diving into cluster installation, configuration, and management. Moving ahead, you’ll explore different approaches while maintaining the Kubernetes cluster, perform upgrades for the Kubernetes cluster, as well as backup and restore etcd. As you advance, you'll deploy and manage workloads on Kubernetes and work with storage for Kubernetes stateful workloads with the help of practical scenarios. You'll also delve into managing the security of Kubernetes applications and understand how different components in Kubernetes communicate with each other and with other applications. The concluding chapters will show you how to troubleshoot cluster- and application-level logging and monitoring, cluster components, and applications in Kubernetes. By the end of this Kubernetes book, you'll be fully prepared to pass the CKA exam and gain practical knowledge that can be applied in your day-to-day work.
Table of Contents (17 chapters)
1
Part 1: Cluster Architecture, Installation, and Configuration
5
Part 2: Managing Kubernetes
10
Part 3: Troubleshooting

Managing container stdout and stderr logs

In the Unix and Linux OSs, there are three I/O streams, called STDIN, STDOUT, and STDERR. Here, we’ll talk about STDOUT and STERR in Linux containers, which are typically what the kubectl logs command shows to us.

STDOUT is usually a command’s normal output, and STDERR is typically used to output error messages. Kubernetes uses the kubectl logs <podname> command to log STDOUT and STDERR. It looks like the following when we use the command to log the nginx pod that we deployed in this chapter:

kubectl logs nginx

The output should look like the following:

Figure 8.10 – kubectl logs nginx pod

Now, we’ll use a container to write text to the standard output stream with a frequency of once per second. We can do this by deploying a new pod. The following is an example of a YAML manifest for this pod:

apiVersion: v1
kind: Pod
metadata:
  name: logger
spec...