about Yarn Cluster Metrics API's return value

[daily]

I confuse about Yarn Cluster Metrics API ( 
http://rm-http-address:port/ws/v1/cluster/metrics ), it does't get the correct 
info in my cluster.Did I misunderstand some properties?


(hadoop version=2.7.3)

1) The number of applications in my cluster is like below ( total=18) :
         ACCEPTED   3  
     RUNNING   5  
     FINISHED   6  
     FAILED   4  
     KILLED   0   
 


2) Yarn UI ( http://rm-http-address:port/cluster/apps ) info is like below 
(apps completed=7 ) :



3) I use Cluster Metrics API ( 
http://rm-http-address:port/ws/v1/cluster/metrics to get ) to get Yarn 
applications, the info is like below (apps completed=5 ) :



so, i get three different result.


Did I misunderstand some properties?


thanks.
Best regards.