Kubernetes: How to Create and Use ConfigMap from Multiple Files

Kubernetes: How to Create and Use ConfigMap from Multiple Files

Kubernetes, the open-source platform for automating deployment, scaling, and management of containerized applications, is a powerful tool for data scientists. One of its many features is ConfigMap, which allows you to decouple configuration artifacts from image content to keep containerized applications portable. In this blog post, we’ll dive into how to create and use ConfigMap from multiple files.

What is ConfigMap?

ConfigMap is a Kubernetes object used to store non-confidential data in key-value pairs. It allows you to separate your application’s configuration from your code, making your application easier to scale and manage. ConfigMaps can be used to store configuration files, command-line arguments, environment variables, and other configuration artifacts.

Creating a ConfigMap from Multiple Files

Creating a ConfigMap from multiple files is straightforward. Let’s assume we have two configuration files, app_config1.yaml and app_config2.yaml.

app_config1.yaml:
apiVersion: v1
kind: ConfigMap
metadata:
  name: example-config
data:
  # property-like keys; each key maps to a simple value
  game.properties: |
    enemies=aliens
    lives=3

app_config2.yaml:
apiVersion: v1
kind: ConfigMap
metadata:
  name: example-config
data:
  # file-like keys
  game.json: |
    {
      "game": {
        "secret": "0123456789",
        "difficulty": "hard"
      }
    }

To create a ConfigMap from these files, use the kubectl create configmap command followed by the name you want to assign to the ConfigMap and the files you want to include.

kubectl create configmap game-config --from-file=app_config1.yaml --from-file=app_config2.yaml

This command will create a ConfigMap named game-config that includes the data from both app_config1.yaml and app_config2.yaml.

Using a ConfigMap

Once you’ve created a ConfigMap, you can use it in your Kubernetes Pods. Here’s an example of how to do it:

apiVersion: v1
kind: Pod
metadata:
  name: configmap-demo-pod
spec:
  containers:
    - name: demo
      image: game_image
      volumeMounts:
      - name: config-volume
        mountPath: /config
  volumes:
    - name: config-volume
      configMap:
        # Provide the name of the ConfigMap you want to mount.
        name: game-config

In this example, the game-config ConfigMap is mounted as a volume to the path /config in the configmap-demo-pod Pod. The configuration data can then be accessed from this path.

Conclusion

Kubernetes ConfigMaps provide a flexible and efficient way to manage application configurations. By decoupling configuration from code, ConfigMaps make your applications more portable and easier to scale. Whether you’re working with a single configuration file or multiple ones, creating and using ConfigMaps is a straightforward process that can greatly simplify your application management tasks.

Remember, while ConfigMaps are great for storing non-sensitive data, they should not be used for sensitive data like passwords or API keys. For that, consider using Kubernetes Secrets.

Keywords

• Kubernetes
• ConfigMap
• Configuration
• Application Management
• Scaling
• Pods
• Secrets

Meta Description

Learn how to create and use Kubernetes ConfigMaps from multiple files. This guide provides a step-by-step process for managing application configurations using ConfigMaps.

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