Hi @Harsh J   You mentioning the Safe Valve gave me an idea! I thought maybe the UI in CM is not setting one or both of those key/values. So I did this manually and it worked! Now every container asked by Spark Pipe() has the same owner as the Spark application itself (no more nobody or yarn! - there must be something with the UI that won't map one of those two configs back to yarn-site.xml):   ... View more