HDFS-17237. Remove IPCLoggerChannelMetrics when the logger is closed

[sodonnel]

Description of PR

When an IPCLoggerChannel is created (which is used to read from and write to the Journal nodes) it also creates a metrics object. When the namenodes failover, the IPC loggers are all closed and reopened in read mode on the new SBNN or the read mode is closed on the SBNN and re-opened in write mode. The closing frees the resources and discards the original IPCLoggerChannel object and causes a new one to be created by the caller.

If a Journal node was down and added back to the cluster with the same hostname, but a different IP, when the failover happens, you end up with 4 metrics objects for the JNs:

1. For for each of the original 3 IPs
2. One for the new IP

The old stale metric will remain forever and will no longer be updated, leading to confusing results in any tools that use the metrics for monitoring.

This change, ensures we un-register the metrics when the logger channel is closed and a new metrics object gets created when the new channel is created.

For info, the logger metrics look like:

{
   "name" : "Hadoop:service=NameNode,name=IPCLoggerChannel-192.168.32.8-8485",
    "modelerType" : "IPCLoggerChannel-192.168.32.8-8485",
    "tag.Context" : "dfs",
    "tag.IsOutOfSync" : "false",
    "tag.Hostname" : "957e3e66f10b",
    "QueuedEditsSize" : 0,
    "LagTimeMillis" : 0,
    "CurrentLagTxns" : 0
  }

Note the name includes the IP, rather than the hostname.

How was this patch tested?

I have added a small test to prove this, but also reproduced the original issue on a docker cluster and validated it is resolved with this change in place.

[hadoop-yetus]

💔 -1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	12m 8s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	codespell	0m 0s		codespell was not available.
+0 🆗	detsecrets	0m 0s		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	44m 5s		trunk passed
+1 💚	compile	1m 16s		trunk passed with JDK Ubuntu-11.0.20.1+1-post-Ubuntu-0ubuntu120.04
+1 💚	compile	1m 12s		trunk passed with JDK Private Build-1.8.0_382-8u382-ga-1~20.04.1-b05
+1 💚	checkstyle	1m 8s		trunk passed
+1 💚	mvnsite	1m 22s		trunk passed
-1 ❌	javadoc	1m 5s	/branch-javadoc-hadoop-hdfs-project_hadoop-hdfs-jdkUbuntu-11.0.20.1+1-post-Ubuntu-0ubuntu120.04.txt	hadoop-hdfs in trunk failed with JDK Ubuntu-11.0.20.1+1-post-Ubuntu-0ubuntu120.04.
+1 💚	javadoc	1m 36s		trunk passed with JDK Private Build-1.8.0_382-8u382-ga-1~20.04.1-b05
+1 💚	spotbugs	3m 12s		trunk passed
+1 💚	shadedclient	34m 19s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+1 💚	mvninstall	1m 10s		the patch passed
+1 💚	compile	1m 13s		the patch passed with JDK Ubuntu-11.0.20.1+1-post-Ubuntu-0ubuntu120.04
+1 💚	javac	1m 13s		the patch passed
+1 💚	compile	1m 3s		the patch passed with JDK Private Build-1.8.0_382-8u382-ga-1~20.04.1-b05
+1 💚	javac	1m 3s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	0m 57s		hadoop-hdfs-project/hadoop-hdfs: The patch generated 0 new + 9 unchanged - 3 fixed = 9 total (was 12)
+1 💚	mvnsite	1m 12s		the patch passed
-1 ❌	javadoc	0m 51s	/patch-javadoc-hadoop-hdfs-project_hadoop-hdfs-jdkUbuntu-11.0.20.1+1-post-Ubuntu-0ubuntu120.04.txt	hadoop-hdfs in the patch failed with JDK Ubuntu-11.0.20.1+1-post-Ubuntu-0ubuntu120.04.
+1 💚	javadoc	1m 27s		the patch passed with JDK Private Build-1.8.0_382-8u382-ga-1~20.04.1-b05
+1 💚	spotbugs	3m 10s		the patch passed
+1 💚	shadedclient	34m 14s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
+1 💚	unit	209m 29s		hadoop-hdfs in the patch passed.
+1 💚	asflicense	0m 42s		The patch does not generate ASF License warnings.
		356m 44s

Subsystem	Report/Notes
Docker	ClientAPI=1.43 ServerAPI=1.43 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-6217/1/artifact/out/Dockerfile
GITHUB PR	#6217
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[arp7]

LGTM. +1 binding. Thanks for fixing this Stephen.

[sodonnel]

Merged to trunk. Thanks for the review @arp7