Using ConfigMaps in Pods

Introduction

ConfigMaps in Kubernetes allow you to decouple configuration artifacts from image content to keep containerized applications portable. This lesson will cover how to create and use ConfigMaps within your Pods.

What is a ConfigMap?

A ConfigMap is an API object used to store non-confidential data in key-value pairs. ConfigMaps can be used to configure application settings, environment variables, command-line arguments, or configuration files.

Creating a ConfigMap

There are several ways to create a ConfigMap:

1. From literal values
2. From files
3. From directories

1. From Literal Values

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

2. From a File

kubectl create configmap my-config --from-file=path/to/config.txt

3. From a Directory

kubectl create configmap my-config --from-file=path/to/directory/

Using ConfigMaps in Pods

Once you've created a ConfigMap, you can use it in your Pods. A ConfigMap can be consumed as:

• Environment Variables
• Command-line Arguments
• Configuration Files in Volumes

Using ConfigMap as Environment Variables

apiVersion: v1
kind: Pod
metadata:
  name: mypod
spec:
  containers:
  - name: mycontainer
    image: myimage
    env:
    - name: MY_ENV_VAR
      valueFrom:
        configMapKeyRef:
          name: my-config
          key: key1

Using ConfigMap in a Volume

apiVersion: v1
kind: Pod
metadata:
  name: mypod
spec:
  containers:
  - name: mycontainer
    image: myimage
    volumeMounts:
    - name: config-volume
      mountPath: /etc/config
  volumes:
  - name: config-volume
    configMap:
      name: my-config

Best Practices

• Use meaningful names for your ConfigMaps.
• Keep your ConfigMaps small and focused.
• Use versioning in your configuration to manage updates effectively.
• Document the purpose of each key in your ConfigMaps.

FAQ