Eventually what I discovered is two things: * The NPE in GssKrb5Base seems to be just a sign that the connection was closed. I suspect this is just a consequence of the NN shutting down without closing a connection. * Essentially the disk the journals was on was just too busy at certain times. By adjusting the disk storage this problem was resolved. Ultimately, I needed to have the YARN resource manager on a different disk than the name node and journal processes. ... View more