HBASE-30257 Fix case-sensitive hostname check in region server

[taklwu]

No description provided.

[Copilot]

Pull request overview

This PR (HBASE-30257) addresses a RegionServer startup failure scenario where the master-provided hostname check could incorrectly fail due to case-sensitive hostname comparisons. It introduces a shared utility for hostname equality and switches the RegionServer check to use it.

Changes:

• Add Strings.hostnamesEqual for case-insensitive DNS hostname comparisons.
• Update HRegionServer to use the new hostname comparison helper during report-for-duty handling.
• Add unit tests covering the new hostname comparison behavior.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java	Uses Strings.hostnamesEqual to avoid case-sensitive hostname mismatch during RS startup.
hbase-common/src/main/java/org/apache/hadoop/hbase/util/Strings.java	Introduces hostnamesEqual helper for hostname/IP identifier comparison.
hbase-common/src/test/java/org/apache/hadoop/hbase/util/TestStrings.java	Adds unit tests for Strings.hostnamesEqual.

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[vaijosh]

LGTM

[PDavid]

Many thanks for fixing this. 👍

Minor: It seems spotless is complaining for formatting in the GH action build.

[anmolnar]

Copilot's concern is valid.

[anmolnar]

Copilot's concern is valid.

Just noticed that you've already applied the fix. Still reusing stuff in HBaseHostnameVerifier is worth to consider.

[taklwu]

Copilot's concern is valid.

Just noticed that you've already applied the fix. Still reusing stuff in HBaseHostnameVerifier is worth to consider.

HBaseHostnameVerifier is a private class in hbase-common, your comment for reusing the those functions e.g. parseIpAddress would require moving/refactoring those functions into a public class e.g. Strings that HRegionServer can access.

I will give a try, but if that refactoring is not what you expected, please let me know.

[taklwu]

failure should not be related, but I triggered a rerun.

[ERROR] Failures: 
[ERROR] org.apache.hadoop.hbase.replication.TestEditsBehindDroppedTableTiming.testEditsBehindDroppedTableTiming
[ERROR]   Run 1: TestEditsBehindDroppedTableTiming.testEditsBehindDroppedTableTiming:107->ReplicationDroppedTablesTestBase.verifyReplicationProceeded:161 Waited too much time for put replication
[ERROR]   Run 2: TestEditsBehindDroppedTableTiming.testEditsBehindDroppedTableTiming:107->ReplicationDroppedTablesTestBase.verifyReplicationProceeded:161 Waited too much time for put replication
[ERROR]   Run 3: TestEditsBehindDroppedTableTiming.testEditsBehindDroppedTableTiming:107->ReplicationDroppedTablesTestBase.verifyReplicationProceeded:161 Waited too much time for put replication