Does Impala uses fair scheduler? and YARN for execution of query?

[#1]

Hi Friends,
I have little doubt about Impala using fair schedulre for launching job. 
I am reading about Impala since 3 months but I never come across about Impala using fair scheduler instead it has its own mechanism for resource allocation. 
Is there any situation where Impala uses fair scheduler during execution of query?

I have one more doubt about IMPALA using YARN. 
I want to the scenario/condition when we have to use YARN with IMPALA, becuase IMPALA has its own execution engine. When we have to use YARN with IMPALA? 

I think Llama is meant for that only.

[#2 · Accepted solution]

I think https://www.cloudera.com/documentation/enterprise/latest/topics/impala_admission.html#admission_yarn largely answers your question.

There's no supported YARN/Impala integration - they each manage their own resources separately. LLAMA was an integration point but it was deprecated and removed from Impala several years ago.

[#3]

Thank you very much Tim.
Provided link has clarified my doubt.