Anatoly created HDFS-17421:
------------------------------

             Summary: Check the correctness of the calculation 
RpcAuthentication*
                 Key: HDFS-17421
                 URL: https://issues.apache.org/jira/browse/HDFS-17421
             Project: Hadoop HDFS
          Issue Type: Test
          Components: hdfs, metrics
            Reporter: Anatoly


I wanted to calculate the load on the KDC in the hadoop cluster after enabling 
kerberos.

There are two parameters in hdfs metrics

 
{code:java}
RpcAuthenticationSuccesses - Total number of authentication successes
RpcAuthenticationFailures - Total number of authentication failures
{code}
 

I expect that any request to the cluster will generate a request to KDC -> get 
ticket and the request counter should trigger either +1 to one metric if 
successful or +1 to another metric if failed

However, on the test cluster, where I have 4 data Nodes and 2 NameNodes (HA), I 
see completely different indicators for these metrics.

I noticed that the RpcAuthenticationSuccesses readings are gradually increasing 
= +1 in 30 seconds

For example, before a test in a cluster
 # only HDFS-\{NN,DN,JN,ZKFC} and YARN-\{RM,NM} services work
 # All other components that were enabled – hive, spark HistoryServer are 
disabled
 # There are no YARN jobs running and no user requests to hdfs

At the time of the test, the value of the metrics

RpcAuthenticationFailures = 0

RpcAuthenticationSuccesses = 208322

 

*TEST 1*

To check the load, I run the test spark submit spark-examples_2.12-3.5.0.jar 
with num-executors 1

The request was executed for 1 min 20 sec

RpcAuthenticationSuccesses = 208338

In total, 16 points were added during the execution time

+2 can be attributed to those +1 times in 30 seconds. But what does +14 points 
mean?

 

*TEST 2*

RpcAuthenticationFailures = 0

RpcAuthenticationSuccesses = 208388

hdfs dfs -ls /

RpcAuthenticationFailures = 0

RpcAuthenticationSuccesses = 208389

 

*TEST 3*

Turned off -

all DN

Standby NN

All YARN services

I still have

Three JN, ZKFC

One NN Active

The +1 counter continues to add +1 to the RpcAuthenticationSuccesses metric 
every 30 seconds

 

Either I don't understand the meaning of these metrics correctly or something 
is not considered right



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