TEZ-4735: Use Ephemeral Sequential Znodes for applicationID generation

[tanishq-chugh]

No description provided.

[tanishq-chugh]

@ayushtkn
As discussed, we need to make the new application IDs generated to be unique in the namespace as the re-usage can lead to dag missing issues on the newly spawned AMs with re-used IDs. The usage of ephemeral sequential Znodes for AMs seems to be the most appropriate choice as it always produces the next sequential unused ID. Other alternatives including usage of current timestamps do not seem appropriate as it diverges from the consistent AM IDs in a cluster, followed as a practise in yarn.
Could you please help with a review on this?
Thanks!

[ayushtkn]

The logic seems fair enough to me, We checked even RM code in Hadoop, it never reuses the id.

[tez-yetus]

🎊 +1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 7s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+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.
			_ master Compile Tests _
+1 💚	mvninstall	2m 59s		master passed
+1 💚	compile	2m 30s		master passed
+1 💚	checkstyle	0m 28s		master passed
+1 💚	javadoc	0m 21s		master passed
+0 🆗	spotbugs	0m 57s		tez-dag in master has 537 extant spotbugs warnings.
			_ Patch Compile Tests _
+1 💚	mvninstall	2m 17s		the patch passed
+1 💚	codespell	0m 47s		No new issues.
+1 💚	compile	2m 32s		the patch passed
+1 💚	javac	2m 32s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	0m 24s		the patch passed
+1 💚	javadoc	0m 21s		the patch passed
+1 💚	spotbugs	1m 8s		the patch passed
			_ Other Tests _
+1 💚	unit	60m 21s		root in the patch passed.
+1 💚	asflicense	0m 23s		The patch does not generate ASF License warnings.
		76m 41s

Subsystem	Report/Notes
Docker	ClientAPI=1.55 ServerAPI=1.55 base: https://ci-hadoop.apache.org/job/tez-multibranch/job/PR-518/4/artifact/out/Dockerfile
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Build tool	maven
Personality	tez-personality.sh
git revision	master / d53e67d
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Test Results	https://ci-hadoop.apache.org/job/tez-multibranch/job/PR-518/4/testReport/
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modules	C: tez-dag U: tez-dag
Console output	https://ci-hadoop.apache.org/job/tez-multibranch/job/PR-518/4/console
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