Yarn-Service is not launched with higher priority by HS2

In Hive 3.x, Yarn-Service is used to launch llap-daemons. If a container (llap-daemon) is killed and there are pending Tez AMs, the llap-daemon container might not get launched as the available resources can be utilized by Tez AMs.

This happens as Yarn-Service and Tez AMs both are launched with the same Yarn Application priority (0). Due to this, which of the two would get the resource is uncertain.

In the previous versions on Hive, this issue was not present as Slider was launched with priority 1. And Tez AMs are launched with priority 0.