Learn Kubernetes: ConfigMap — Inject the values of a ConfigMap in a container as a volume

In this series of stories, you will learn how to use Kubernetes. Today, let’s inject the values of a ConfigMap in a container as a volume.

After this story, you can read the following stories:

• Storing configuration in ConfigMap,
• Inject the values of a ConfigMap in a container as environment variables,
• Inject the values of a ConfigMap in a container as a volume,
• Multiple ways to modify a ConfigMap,
• Two solutions to update the deployment following a change in the ConfigMap.

In first, let’s store the Nginx configuration file nginx.conf in a ConfigMap:

kubectl create configmap nginx-config --from-file=./nginx.conf

If the command succeeds, the output is:

configmap/nginx-config created

Confirm that the contents of the nginx.conf file are in the data: section of the ConfigMap:

kubectl get cm nginx-config -o yaml

The output is similar to:

apiVersion: v1
data:
  nginx.conf: |
    server {
        listen 80;
root /usr/share/nginx/html;
    }
kind: ConfigMap
metadata:
  creationTimestamp: "2022-02-21T09:46:18Z"
  managedFields:
  - apiVersion: v1
    fieldsType: FieldsV1
    fieldsV1:
      f:data:
        .: {}…