To get the number of vcores and memory used for a particular queue in the cluster
You can get this information in the cluster utilization report, please go through the below doc for more information:
https://docs.cloudera.com/documentation/enterprise/6/6.3/topics/admin_cluster_util_report.html
Also, if you want to see the resources used for each application, please go through the below KB article:
https://my.cloudera.com/knowledge/How-to-calculate-memory-and-v-core-utilization-for-each-of-the?id=...
another option is
Using yarn application -status command, you can get the Aggregate Resource Allocation for an application.
For e.g. yarn application -status application_ID (for one of completed applications), one of the rows returned is:
Aggregate Resource Allocation : 46641 MB-seconds, 37 vcore-seconds
This gives an aggregate memory and CPU allocations in seconds.