title: Create environment variables for Kubernetes main container in Kubernetes Init container
body: <p>I use an Kubernetes Init container to provision the application's database. After this is done I want to provide the DB's credentials to the main container via environment variables.</p>
  <p>How can this be achieved?</p>
  <p>I don't want to create a Kubernetes Secret inside the Init container, since I don't want to save the credentials there!</p>