At first save output of kubect get nodes command into JSON file:

$ exampleCommand > node-info.json

Then create proper ConfigMap.

Here is an example:

apiVersion: v1
kind: ConfigMap
metadata:
  name: example-config
data:
  node-info.json: |
    {
      "array": [
        1,
        2
      ],
      "boolean": true,
      "number": 123,
      "object": {
        "a": "egg",
        "b": "egg1"
      },
      "string": "Welcome"
    }

Then remember to add following lines below specification section in pod configuration file:

env:
  - name: NODE_CONFIG_JSON
    valueFrom:
      configMapKeyRef:
        name: example-config
        key: node-info.json

You can also use PodPresent.

PodPreset is an object that enable to inject information egg. environment variables into pods during creation time.

Look at the example below:

apiVersion: settings.k8s.io/v1alpha1
kind: PodPreset
metadata:
  name: example
spec:
  selector:
    matchLabels:
      app: your-pod
  env:
    - name: DB_PORT
      value: "6379"
  envFrom:
    - configMapRef:
        name: etcd-env-config
        key: node-info.json

but remember that you have to also add:

env:
  - name: NODE_CONFIG_JSON
    valueFrom:
      configMapKeyRef:
        name: example-config
        key: node-info.json

section to your pod definition proper to your PodPresent and ConfigMap configuration.

More information you can find here: podpresent, pod-present-configuration.

You can save the output of command in any file. Then use the file or data inside file to create configmap. After creating the configmap you can mount it as a file in your deployment/pod.

For example:

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  labels:
    app: appname
  name: appname
  namespace: development
spec:
  selector:
    matchLabels:
      app: appname
      tier: sometier
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: appname
        tier: sometier
    spec:
      containers:
        - env:
            - name: NODE_ENV
              value: development
            - name: PORT
              value: "3000"
            - name: SOME_VAR
              value: xxx
          image: someimage
          imagePullPolicy: Always
          name: appname
          volumeMounts:
            - name: your-volume-name
              mountPath: "your/path/to/store/the/file"
              readOnly: true
      volumes:
        - name: your-volume-name
          configMap:
            name: your-configmap-name
            items:
              - key: your-filename-inside-pod
                path: your-filename-inside-pod

I added the following configuration in deployment:

      volumeMounts:
        - name: your-volume-name
          mountPath: "your/path/to/store/the/file"
          readOnly: true
  volumes:
    - name: your-volume-name
      configMap:
        name: your-configmap-name
        items:
          - key: your-filename-inside-pod
            path: your-filename-inside-pod

To create ConfigMap from file:

kubectl create configmap your-configmap-name --from-file=your-file-path

Or just create ConfigMap with the output of your command:

apiVersion: v1
kind: ConfigMap
metadata:
  name: your-configmap-name
  namespace: your-namespace
data:
  your-filename-inside-pod: |
    output of command