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Posted to jira@kafka.apache.org by "Haruki Okada (Jira)" <ji...@apache.org> on 2021/10/27 01:39:00 UTC
[jira] [Commented] (KAFKA-13403) KafkaServer crashes when deleting
topics due to the race in log deletion
[ https://issues.apache.org/jira/browse/KAFKA-13403?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17434630#comment-17434630 ]
Haruki Okada commented on KAFKA-13403:
--------------------------------------
[~showuon] Already working on it? or may I.
> KafkaServer crashes when deleting topics due to the race in log deletion
> ------------------------------------------------------------------------
>
> Key: KAFKA-13403
> URL: https://issues.apache.org/jira/browse/KAFKA-13403
> Project: Kafka
> Issue Type: Bug
> Components: core
> Affects Versions: 2.4.1
> Reporter: Haruki Okada
> Assignee: Luke Chen
> Priority: Major
>
> h2. Environment
> * OS: CentOS Linux release 7.6
> * Kafka version: 2.4.1
> *
> ** But as far as I checked the code, I think same phenomenon could happen even on trunk
> * Kafka log directory: RAID1+0 (i.e. not using JBOD so only single log.dirs is set)
> * Java version: AdoptOpenJDK 1.8.0_282
> h2. Phenomenon
> When we were in the middle of deleting several topics by `kafka-topics.sh --delete --topic blah-blah`, one broker in our cluster crashed due to following exception:
>
> {code:java}
> [2021-10-21 18:19:19,122] ERROR Shutdown broker because all log dirs in /data/kafka have failed (kafka.log.LogManager)
> {code}
>
>
> We also found NoSuchFileException was thrown right before the crash when LogManager tried to delete logs for some partitions.
>
> {code:java}
> [2021-10-21 18:19:18,849] ERROR Error while deleting log for foo-bar-topic-5 in dir /data/kafka (kafka.server.LogDirFailureChannel)
> java.nio.file.NoSuchFileException: /data/kafka/foo-bar-topic-5.df3626d2d9eb41a2aeb0b8d55d7942bd-delete/00000000000003877066.timeindex.deleted
> at sun.nio.fs.UnixException.translateToIOException(UnixException.java:86)
> at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102)
> at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:107)
> at sun.nio.fs.UnixFileAttributeViews$Basic.readAttributes(UnixFileAttributeViews.java:55)
> at sun.nio.fs.UnixFileSystemProvider.readAttributes(UnixFileSystemProvider.java:144)
> at sun.nio.fs.LinuxFileSystemProvider.readAttributes(LinuxFileSystemProvider.java:99)
> at java.nio.file.Files.readAttributes(Files.java:1737)
> at java.nio.file.FileTreeWalker.getAttributes(FileTreeWalker.java:219)
> at java.nio.file.FileTreeWalker.visit(FileTreeWalker.java:276)
> at java.nio.file.FileTreeWalker.next(FileTreeWalker.java:372)
> at java.nio.file.Files.walkFileTree(Files.java:2706)
> at java.nio.file.Files.walkFileTree(Files.java:2742)
> at org.apache.kafka.common.utils.Utils.delete(Utils.java:732)
> at kafka.log.Log.$anonfun$delete$2(Log.scala:2036)
> at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
> at kafka.log.Log.maybeHandleIOException(Log.scala:2343)
> at kafka.log.Log.delete(Log.scala:2030)
> at kafka.log.LogManager.deleteLogs(LogManager.scala:826)
> at kafka.log.LogManager.$anonfun$deleteLogs$6(LogManager.scala:840)
> at kafka.utils.KafkaScheduler.$anonfun$schedule$2(KafkaScheduler.scala:116)
> at kafka.utils.CoreUtils$$anon$1.run(CoreUtils.scala:65)
> at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
> at java.util.concurrent.FutureTask.run(FutureTask.java:266)
> at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
> at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
> at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
> at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
> at java.lang.Thread.run(Thread.java:748)
> {code}
> So, the log-dir was marked as offline and ended up with KafkaServer crash because the broker has only single log-dir.
> h2. Cause
> We also found below logs right before the NoSuchFileException.
>
> {code:java}
> [2021-10-21 18:18:17,829] INFO Log for partition foo-bar-5 is renamed to /data/kafka/foo-bar-5.df3626d2d9eb41a2aeb0b8d55d7942bd-delete and is scheduled for deletion (kafka.log.LogManager)
> [2021-10-21 18:18:17,900] INFO [Log partition=foo-bar-5, dir=/data/kafka] Found deletable segments with base offsets [3877066] due to retention time 172800000ms breach (kafka.log.Log)[2021-10-21 18:18:17,901] INFO [Log partition=foo-bar-5, dir=/data/kafka] Scheduling segments for deletion List(LogSegment(baseOffset=3877066, size=90316366, lastModifiedTime=1634634956000, largestTime=1634634955854)) (kafka.log.Log)
> {code}
> After checking through Kafka code, we concluded that there was a race between "kafka-log-retention" and "kafka-delete-logs" scheduler threads.
>
> Detailed timeline was like below:
> - Precondition: there was two log segments (3877066, 4271262) for the partition foo-bar-5
>
> ||time||thread||event||files under partition dir||
> |2021-10-21 18:18:17,901|kafka-log-retention|Scheduled deletion for segment 3877066 due to retention|3877066, 4271262|
> |2021-10-21 18:19:17,830|kafka-delete-logs|Starting to execute Log.delete() (which was scheduled by topic deletion)
>
> Deleted all log segments ([https://github.com/apache/kafka/blob/2.4.1/core/src/main/scala/kafka/log/Log.scala#L2031])
> However, in the meantim, 3877066 was scheduled for deletion due to retention and already removed from segment-list, 3877066 was not listed up as deletion target here.|3877066|
> |2021-10-21 18:19:17,830 + X|kafka-delete-logs|Start deleting entire partition directory by calling Utils.delete() ([https://github.com/apache/kafka/blob/2.4.1/clients/src/main/java/org/apache/kafka/common/utils/Utils.java#L729])
>
> Files.walkFileTree starts to walk inside the directory, and found 3877066|3877066|
> |2021-10-21 18:19:17,830 + X|kafka-log-retention|Delete segment 3877066 as scheduled|empty|
> |2021-10-21 18:19:18,849|kafka-delete-logs|Files.walkFileTree tried to read attributes of 3877066 but it failed with NoSuchFileException|empty|
> h2. Suggested solution
> * I would like to suggest to fix Utils.delete to swallow NoSuchFileException and just returns FileVisitResult.CONTINUE here
> ** [https://github.com/apache/kafka/blob/2.4.1/clients/src/main/java/org/apache/kafka/common/utils/Utils.java#L736]
> * Also, we should use Files.deleteIfExists here
> ** [https://github.com/apache/kafka/blob/2.4.1/clients/src/main/java/org/apache/kafka/common/utils/Utils.java#L743]
> ** Though it was not the case for our situation, this could lead NoSuchFileException too because the file might be deleted by another thread by same flow.
> * What Utils.delete does is just deleting children recursively, so NoSuchFileException just means we don't have to delete it, so ignoring it and continuing should be safe.
>
>
>
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