Unfortunately, Phoenix (HBase) is not yet integrated in YARN by default (HDP 2.6.5 or lower, 3.x I don't know). So the ressources of HBase loads are managed outside of YARN. That's the reason why it is recommended that the YARN Property yarn.nodemanager.resource.memory-mb should not set to all your cluster ressources. There should be enough space for HBase workloads and things like the Operating System. However, there are some workarounds to manage Phoenix/HBase Ressources.
Manage in YARN
Use Spark with Phoenix JDBC Connector - Spark runs on YARN, but i think it's a little bit difficult to run interactive queries
Use Apache - Slider “slides” existing long-running services like Apache HBase onto YARN (but haven't used it yet, so I don't know how it works)