Configuration

Tutorial 4 of 4

Introduction

This tutorial will guide you through the process of managing configurations in Kubernetes using ConfigMaps. ConfigMaps allow you to decouple configuration artifacts from image content to maintain a clean separation between your application code and configuration.

By the end of this tutorial, you will learn how to create, modify, and use ConfigMaps in a Kubernetes cluster.

Prerequisites:

Basic understanding of Kubernetes
Kubernetes cluster up and running
kubectl command-line tool installed

Step-by-Step Guide

Concepts

ConfigMap: It is an API object used to store non-confidential data in key-value pairs. It allows you to decouple environment-specific configuration from your application's image, making your applications portable.
kubectl: It is a command-line tool to interact with the Kubernetes cluster.

Best Practices and Tips

Do not store sensitive information in ConfigMaps. Use secrets for that purpose.
Use labels and annotations to organize ConfigMaps.
Avoid large ConfigMaps that could slow down your Kubernetes deployments.

Code Examples

Example 1: Creating a ConfigMap

First, we will create a ConfigMap using kubectl.

kubectl create configmap my-config --from-literal=key1=value1 --from-literal=key2=value2

In this command:

my-config is the name of the ConfigMap.
--from-literal=key1=value1 and --from-literal=key2=value2 are the key-value pairs stored in the ConfigMap.

After running this command, you should see the following output:

configmap/my-config created

Example 2: Getting a ConfigMap

You can use the following command to get the details of a ConfigMap:

kubectl get configmap my-config

This command will return the following output:

NAME        DATA   AGE
my-config   2      1m

Summary

In this tutorial, we have:

Introduced the concept of ConfigMaps in Kubernetes.
Learned how to create and retrieve ConfigMaps using kubectl.

For further learning, you can explore how to delete ConfigMaps, use ConfigMaps in Pods, and share ConfigMaps between multiple containers.

Practice Exercises

Exercise 1: Create a ConfigMap with more than two key-value pairs.

Solution:

kubectl create configmap my-config --from-literal=key1=value1 --from-literal=key2=value2 --from-literal=key3=value3

Exercise 2: Retrieve the details of the ConfigMap you created in Exercise 1.