title: Kubernetes - Share single file between containers (within the same pod)
body: <p>I have an API that describes itself through an openapi3 file. This app is contained in a pod that also has a sidecar app that is supposed to read this file at startup time.</p>
  
  <p>My probleme is how my sidecar app can read the openapi file from the other container ?</p>
  
  <p>I know I could do it using a volume (emptyDir) and modify the command so my api copies the file at startup time. I'd rather not go this route. I have been looking for a feature, where I define a volume which is mapped to an existing folder in my app, but without being empty. Is there such a thing ?</p>