<p>The aim behind this question is to know how having a file inside a Pod, if we use ConfigMap, I don't want to apply changes if the configMap will change</p>

<p>Thanks</p>

<p>I am not really understanding, why don't you want to use a volume? 
A proper way, to mount a confgimap to a pod looks like this:
Configmap- specify name of the file in a <code>data</code> section:</p>

<pre><code>apiVersion: v1
kind: ConfigMap
metadata:
  creationTimestamp: 2016-02-18T18:52:05Z
  name: txt-file-configmap
  namespace: default
  resourceVersion: "516"
  selfLink: /api/v1/namespaces/default/configmaps/game-config
  uid: b4952dc3-d670-11e5-8cd0-68f728db1985
data:
  file.txt: |
    here
    are
    filecontents
</code></pre>

<p>And in a pod, specify a volume with a configmap name and volumeMount, pointing a path, where to mount the volume:</p>

<pre><code>apiVersion: v1
kind: Pod
metadata:
  name: dapi-test-pod
spec:
  containers:
    - name: test-container
      image: k8s.gcr.io/busybox
      command: [ "/bin/sh", "-c", "cat /etc/txtfiles/file.txt" ]
      volumeMounts:
      - name: txt-file
        mountPath: /etc/txtfiles
  volumes:
    - name: txt-file
      configMap:
        name: txt-file-configmap
</code></pre>

<p>The example pod which I provided you, will have the configmap mounted as a file and will print it's contents.</p>
