HDFS-16456. EC: Decommission a rack with only one dn will fail when the rack number is equal with replication (#4126)

[jojochuang]

(cherry picked from commit cee8c62)

Conflicts:
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/NetworkTopology.java

Change-Id: I5da7693d6176315f126f1b5107de2bb100ee9778

Description of PR

(HDFS-16456 was merged in trunk. It has conflict in branch-3.3 because of HDFS-15263. It looks like HDFS-15263 could potentially change the behavior and surprise users, so decided to backport without HDFS-15263)

How was this patch tested?

For code changes:

• Does the title or this PR starts with the corresponding JIRA issue id (e.g. 'HADOOP-17799. Your PR title ...')?
• Object storage: have the integration tests been executed and the endpoint declared according to the connector-specific documentation?
• If adding new dependencies to the code, are these dependencies licensed in a way that is compatible for inclusion under ASF 2.0?
• If applicable, have you updated the LICENSE, LICENSE-binary, NOTICE-binary files?

[hadoop-yetus]

💔 -1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	11m 3s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	codespell	0m 0s		codespell was not available.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
+1 💚	test4tests	0m 0s		The patch appears to include 2 new or modified test files.
			_ branch-3.3 Compile Tests _
+0 🆗	mvndep	15m 42s		Maven dependency ordering for branch
+1 💚	mvninstall	23m 44s		branch-3.3 passed
+1 💚	compile	21m 44s		branch-3.3 passed
+1 💚	checkstyle	3m 47s		branch-3.3 passed
+1 💚	mvnsite	4m 25s		branch-3.3 passed
+1 💚	javadoc	4m 33s		branch-3.3 passed
+1 💚	spotbugs	6m 51s		branch-3.3 passed
+1 💚	shadedclient	28m 26s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+0 🆗	mvndep	0m 32s		Maven dependency ordering for patch
-1 ❌	mvninstall	0m 49s	/patch-mvninstall-hadoop-hdfs-project_hadoop-hdfs.txt	hadoop-hdfs in the patch failed.
-1 ❌	compile	2m 50s	/patch-compile-root.txt	root in the patch failed.
-1 ❌	javac	2m 50s	/patch-compile-root.txt	root in the patch failed.
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	2m 29s		the patch passed
-1 ❌	mvnsite	0m 54s	/patch-mvnsite-hadoop-hdfs-project_hadoop-hdfs.txt	hadoop-hdfs in the patch failed.
+1 💚	javadoc	3m 13s		the patch passed
-1 ❌	spotbugs	0m 50s	/patch-spotbugs-hadoop-hdfs-project_hadoop-hdfs.txt	hadoop-hdfs in the patch failed.
-1 ❌	shadedclient	12m 40s		patch has errors when building and testing our client artifacts.
			_ Other Tests _
+1 💚	unit	17m 52s		hadoop-common in the patch passed.
-1 ❌	unit	0m 50s	/patch-unit-hadoop-hdfs-project_hadoop-hdfs.txt	hadoop-hdfs in the patch failed.
+1 💚	asflicense	0m 43s		The patch does not generate ASF License warnings.
		167m 55s

Subsystem	Report/Notes
Docker	ClientAPI=1.41 ServerAPI=1.41 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4304/1/artifact/out/Dockerfile
GITHUB PR	#4304
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell
uname	Linux 8d3f7941228c 4.15.0-65-generic #74-Ubuntu SMP Tue Sep 17 17:06:04 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	branch-3.3 / c387e506e8d0fb76d000ec507f9b44bcaee4fd69
Default Java	Private Build-1.8.0_312-8u312-b07-0ubuntu1~18.04-b07
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4304/1/testReport/
Max. process+thread count	1267 (vs. ulimit of 5500)
modules	C: hadoop-common-project/hadoop-common hadoop-hdfs-project/hadoop-hdfs U: .
Console output	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4304/1/console
versions	git=2.17.1 maven=3.6.0 spotbugs=4.2.2
Powered by	Apache Yetus 0.14.0-SNAPSHOT https://yetus.apache.org

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[hadoop-yetus]

💔 -1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	10m 53s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	codespell	0m 0s		codespell was not available.
+1 💚	@author	0m 1s		The patch does not contain any @author tags.
+1 💚	test4tests	0m 0s		The patch appears to include 2 new or modified test files.
			_ branch-3.3 Compile Tests _
+0 🆗	mvndep	14m 14s		Maven dependency ordering for branch
+1 💚	mvninstall	23m 42s		branch-3.3 passed
+1 💚	compile	18m 3s		branch-3.3 passed
+1 💚	checkstyle	3m 18s		branch-3.3 passed
+1 💚	mvnsite	4m 14s		branch-3.3 passed
+1 💚	javadoc	4m 38s		branch-3.3 passed
+1 💚	spotbugs	7m 0s		branch-3.3 passed
+1 💚	shadedclient	28m 7s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+0 🆗	mvndep	0m 57s		Maven dependency ordering for patch
+1 💚	mvninstall	2m 28s		the patch passed
+1 💚	compile	17m 17s		the patch passed
+1 💚	javac	17m 17s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	3m 13s		the patch passed
+1 💚	mvnsite	4m 12s		the patch passed
+1 💚	javadoc	4m 23s		the patch passed
+1 💚	spotbugs	6m 58s		the patch passed
+1 💚	shadedclient	28m 24s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
+1 💚	unit	18m 3s		hadoop-common in the patch passed.
-1 ❌	unit	239m 44s	/patch-unit-hadoop-hdfs-project_hadoop-hdfs.txt	hadoop-hdfs in the patch passed.
+1 💚	asflicense	1m 51s		The patch does not generate ASF License warnings.
		440m 42s

Reason	Tests
Failed junit tests	hadoop.hdfs.server.balancer.TestBalancerWithHANameNodes

Subsystem	Report/Notes
Docker	ClientAPI=1.41 ServerAPI=1.41 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4304/2/artifact/out/Dockerfile
GITHUB PR	#4304
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell
uname	Linux 50c5cd921baa 4.15.0-65-generic #74-Ubuntu SMP Tue Sep 17 17:06:04 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	branch-3.3 / 509b0f0
Default Java	Private Build-1.8.0_312-8u312-b07-0ubuntu1~18.04-b07
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4304/2/testReport/
Max. process+thread count	2650 (vs. ulimit of 5500)
modules	C: hadoop-common-project/hadoop-common hadoop-hdfs-project/hadoop-hdfs U: .
Console output	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4304/2/console
versions	git=2.17.1 maven=3.6.0 spotbugs=4.2.2
Powered by	Apache Yetus 0.14.0-SNAPSHOT https://yetus.apache.org

This message was automatically generated.

[tasanuma]

@jojochuang Thanks for backporting it. +1.

[jojochuang]

Thanks for the review!