title: Automatically generated strings for secrets using yaml config
body: <p>I have a deployment config for an app, that (among other things) creates a secret for a mysql database:</p>
  
  <pre><code>---
  apiVersion: v1
  kind: Secret
  metadata:
    name: mysql-secret
  type: Opaque
  data:
    MYSQL_USER: my_user
    MYSQL_PASSWORD: my_random_secret
    MYSQL_DATABASE: my_db
    MYSQL_ROOT_PASSWORD: my_random_secret
  ---
  etc...
  </code></pre>
  
  <p>The deployment file is under source control, so I don't want to place the secrets there.</p>
  
  <p>Does anyone know how I can tell Kubernetes to generate random strings for each variable which has <code>my_random_secret</code> as a value in my example? Preferably something that can be configured using the yaml file, without needing to invoke any extra commands.</p>