How to merge two configmaps using volume mount in kubernetes

Question

I am having two different config maps test-configmap and common-config. I tried to mount them at the same location, but one config map over

Answer 1

Another example of how this can be done for mounting multiple configmaps. This for an nginx dock were you want to both replace the main /etc/nginx/nginx.conf and the files in /etc/nginx/conn.f. This also deletes the default.conf file in conf.d

 containers:
    - name: nginx-proxy
      image: nginx:1.16-alpine
      imagePullPolicy: Always
      ports:
        - containerPort: 443
        - containerPort: 80
      volumeMounts:
        - name: nginx-main-conf-file
          mountPath: /etc/nginx/nginx.conf
          subPath: nginx.conf
        - name: nginx-site-conf-file
          mountPath: /etc/nginx/conf.d
  volumes:
    - name: nginx-main-conf-file
      configMap:
        name: nginx-main-conf
    - name: nginx-site-conf-file
      configMap:
        name: nginx-site-conf

And one very important point. If you have any out commented lines (# something) in your yaml file, then this will not work. It's a bug. Tested in kubectl v1.14