Comment 7 for bug 1379276

This issue also happens with a simple MTR test that simply shuts down the slave cleanly and then restarts it, if updates have happened on the master in the meantime.

The unknown exception in question is gu::NotSet

The key that was not set is ist.recv_addr, which means that wsrep_node_address is not being set. And it was not being set by default because autodetection via ifconfig failed due to output not parsable by the default regex.