use an initContainer to write configuration into an empty ephemeral folder

initContainerWriteEmptyDir.sh

#!/bin/bash
cat | oc create -f  - <<EOF
apiVersion: v1
kind: Pod
metadata:
  name: my-app
spec:
  containers:
  - name: realworld
    image: docker.io/simonmassey/react-redux-realworld:v0.0.2
    env:
    - name: API_ROOT
      value: https://conduit.productionready.io/api
    volumeMounts:
    - mountPath: /data
      name: config-data
  initContainers:
  - name: config-data
    image: busybox
    command: ["sh", "-c", "echo {'address':'10.0.1.192:2379/db'} > /data/config"]
    volumeMounts:
    - mountPath: /data
      name: config-data
  volumes:
  - name: config-data
    emptyDir:
      {}
EOF