Hi,
Our team has been using Apache Kafka for over a year.
Recently, we plan to replace the Kafka log directory with a symbolic link.
For example, in the server.properties:
`log.dirs=/some/path/to/logdir`
whereas `/some/path/to/logdir` is a symbolic link to
`/actual/path/to/logdir`. To provide more context, the two paths reside in
different disk partitions.
However, we keep on failing to startup Kafka. Here's the error message:
```
[2024-12-30 18:14:52,434] INFO [ThrottledChannelReaper-ControllerMutation]:
Starting (kafka.server.ClientQuotaManager$ThrottledChannelReaper)
[2024-12-30 18:14:52,444] INFO [KafkaServer id=MYID] Rewriting
/path/to/logdir/meta.properties (kafka.server.KafkaServer)
[2024-12-30 18:14:52,445] ERROR Error while writing meta.properties to
/path/to/logdir
(org.apache.kafka.storage.internals.log.LogDirFailureChannel)
java.nio.file.FileAlreadyExistsException: /path/to/logdir
at
java.base/sun.nio.fs.UnixException.translateToIOException(UnixException.java:94)
at
java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:106)
at
java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:111)
at
java.base/sun.nio.fs.UnixFileSystemProvider.createDirectory(UnixFileSystemProvider.java:397)
at java.base/java.nio.file.Files.createDirectory(Files.java:700)
at
java.base/java.nio.file.Files.createAndCheckIsDirectory(Files.java:807)
at java.base/java.nio.file.Files.createDirectories(Files.java:753)
at kafka.server.KafkaServer.$anonfun$startup$6(KafkaServer.scala:297)
at
org.apache.kafka.metadata.properties.MetaPropertiesEnsemble$Copier.writeLogDirChanges(MetaPropertiesEnsemble.java:373)
at kafka.server.KafkaServer.startup(KafkaServer.scala:302)
at kafka.Kafka$.main(Kafka.scala:112)
at kafka.Kafka.main(Kafka.scala)
[2024-12-30 18:14:52,466] ERROR Failed to create or validate data directory
/path/to/logdir
(org.apache.kafka.storage.internals.log.LogDirFailureChannel)
java.io.IOException: Failed to load /path/to/logdir during broker startup
at
kafka.log.LogManager.$anonfun$createAndValidateLogDirs$1(LogManager.scala:181)
30-12-2024 10:14:52.468: at
scala.collection.IterableOnceOps.foreach(IterableOnce.scala:576)
at scala.collection.IterableOnceOps.foreach$(IterableOnce.scala:574)
at scala.collection.AbstractIterable.foreach(Iterable.scala:933)
at
kafka.log.LogManager.createAndValidateLogDirs(LogManager.scala:178)
at kafka.log.LogManager.<init>(LogManager.scala:105)
at kafka.log.LogManager$.apply(LogManager.scala:1539)
at kafka.server.KafkaServer.startup(KafkaServer.scala:316)
at kafka.Kafka$.main(Kafka.scala:112)
at kafka.Kafka.main(Kafka.scala)
[2024-12-30 18:14:52,469] ERROR Shutdown broker because none of the
specified log dirs from /path/to/logdir can be created or validated
(kafka.log.LogManager)
```
Environment
- Kafka version: 3.7.0 (scala: 2.13)
- Deployment: broker + zookeeper
We suspect the symbolic link is the culprit, because if we set "log.dirs"
to the `/actual/path/to/logdir` directly, there is no such problem.
Interestingly, if we set "log.dirs" to one subfolder deeper, for example
`/some/path/to/logdir/subdir`, it also didn't complain.
I searched the internet but could not find a description saying that
"log.dirs" cannot be a symbolic link, so I am asking for help.
Thanks,
David
