Tim is right. This is almost certainly one of the known issues with Impala's previous YARN integration (via Llama). There were some fixes to that code in Impala 2.4 but you could still get this sort of unexpected failure. It's recommended that you do not use Impala on YARN, and instead to statically allocate resources to Impala for the time being. Cloudera Manager has a feature called "Static Service Pools" that can help with that, but it's not necessary. The CM documentation has more information.
We are working on improving Impala resource management, but it's going to take some time and we don't yet have a target release yet.