YARN-11192. TestRouterWebServicesREST failing after YARN-9827.

[slfan1989]

JIRA: YARN-11192. TestRouterWebServicesREST failing after YARN-9827.

In YARN-9827, the following modifications:

GenericExceptionHandler should respond with SERVICE_UNAVAILABLE in case of connection and service unavailable exception instead of INTERNAL_SERVICE_ERROR. 

This modification caused some of YARN Federation's TestRouterWebServicesREST unit tests to fail

[ERROR] Tests run: 201, Failures: 15, Errors: 0, Skipped: 0, Flakes: 2
.....
[ERROR] org.apache.hadoop.yarn.server.router.webapp.TestRouterWebServicesREST.testUpdateAppStateXML(org.apache.hadoop.yarn.server.router.webapp.TestRouterWebServicesREST)
[ERROR]   Run 1: TestRouterWebServicesREST.testUpdateAppStateXML:774 expected:<500> but was:<503>
[ERROR]   Run 2: TestRouterWebServicesREST.testUpdateAppStateXML:774 expected:<500> but was:<503>
[ERROR]   Run 3: TestRouterWebServicesREST.testUpdateAppStateXML:774 expected:<500> but was:<503> 

Report-URL:

https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4464/5/artifact/out/patch-unit-hadoop-yarn-project_hadoop-yarn_hadoop-yarn-server_hadoop-yarn-server-router.txt

[hadoop-yetus]

🎊 +1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 49s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	codespell	0m 1s		codespell was not available.
+0 🆗	detsecrets	0m 1s		detect-secrets was not available.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
+1 💚	test4tests	0m 0s		The patch appears to include 1 new or modified test files.
			_ trunk Compile Tests _
+1 💚	mvninstall	71m 0s		trunk passed
+1 💚	compile	0m 38s		trunk passed with JDK Private Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1
+1 💚	compile	0m 34s		trunk passed with JDK Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
+1 💚	checkstyle	0m 42s		trunk passed
+1 💚	mvnsite	0m 47s		trunk passed
+1 💚	javadoc	0m 55s		trunk passed with JDK Private Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1
+1 💚	javadoc	0m 32s		trunk passed with JDK Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
+1 💚	spotbugs	1m 5s		trunk passed
+1 💚	shadedclient	23m 29s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+1 💚	mvninstall	0m 34s		the patch passed
+1 💚	compile	0m 28s		the patch passed with JDK Private Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1
+1 💚	javac	0m 28s		the patch passed
+1 💚	compile	0m 25s		the patch passed with JDK Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
+1 💚	javac	0m 25s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	0m 19s		the patch passed
+1 💚	mvnsite	0m 27s		the patch passed
+1 💚	javadoc	0m 23s		the patch passed with JDK Private Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1
+1 💚	javadoc	0m 21s		the patch passed with JDK Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
+1 💚	spotbugs	0m 56s		the patch passed
+1 💚	shadedclient	23m 37s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
+1 💚	unit	3m 8s		hadoop-yarn-server-router in the patch passed.
+1 💚	asflicense	0m 47s		The patch does not generate ASF License warnings.
		133m 33s

Subsystem	Report/Notes
Docker	ClientAPI=1.41 ServerAPI=1.41 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4484/1/artifact/out/Dockerfile
GITHUB PR	#4484
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell detsecrets
uname	Linux 252501c8a439 4.15.0-175-generic #184-Ubuntu SMP Thu Mar 24 17:48:36 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	trunk / b1ff8d4
Default Java	Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
Multi-JDK versions	/usr/lib/jvm/java-11-openjdk-amd64:Private Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1 /usr/lib/jvm/java-8-openjdk-amd64:Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4484/1/testReport/
Max. process+thread count	1234 (vs. ulimit of 5500)
modules	C: hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router U: hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router
Console output	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4484/1/console
versions	git=2.25.1 maven=3.6.3 spotbugs=4.2.2
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[slfan1989]

@goiri @ayushtkn Please help me to review the code, Thank you very much!

[ayushtkn]

The test passes here:
https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4484/1/testReport/org.apache.hadoop.yarn.server.router.webapp/TestRouterWebServicesREST/

Changes makes sense to me

[slfan1989]

@ayushtkn Thanks for your help reviewing the code!

[zhengchenyu]

LGTM +1, #4450 is blocked by this.