Skip to content

HBASE-30060: Add documentation about addressing multiple SLF4J bindings #8029

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
taklwu merged 1 commit into from
Apr 9, 2026
+22 −0
Merged

HBASE-30060: Add documentation about addressing multiple SLF4J bindings #8029

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
22 changes: 22 additions & 0 deletions hbase-website/app/pages/_docs/docs/_mdx/(multi-page)/troubleshooting.mdx
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -55,6 +55,28 @@ To disable, set the logging level back to `INFO` level.

The same log settings also work on Master and for the client.

## Handling Multiple SLF4J Bindings to Prevent Overridden Log Configurations

If you have a local installation of Hadoop (e.g., installed via Homebrew on macOS), you may encounter a "multiple SLF4J bindings" warning when starting HBase in standalone mode using `bin/start-hbase.sh`. For example, you may see the following when starting HBase on your machine:

```text
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/opt/homebrew/Cellar/hadoop/3.4.1/libexec/share/hadoop/common/lib/slf4j-reload4j-1.7.36.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:$HOME/.m2/repository/org/apache/logging/log4j/log4j-slf4j-impl/2.25.3/log4j-slf4j-impl-2.25.3.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Reload4jLoggerFactory]
```

This is happening because the `bin/hbase` script automatically detects local Hadoop installations and adds their classpath to HBase. If your Hadoop installation uses the legacy Reload4j (or Log4j 1.2) binder, SLF4J may prioritize it over the HBase Log4j2 binder. When this happens, your `conf/log4j2.properties` file and `HBASE_ROOT_LOGGER` environment variable are completely ignored.

To get around this issue, you can set `HBASE_DISABLE_HADOOP_CLASSPATH_LOOKUP` to `true`. You can modify this directly in `conf/hbase-env.sh` by uncommenting the following line:

```bash
export HBASE_DISABLE_HADOOP_CLASSPATH_LOOKUP="true"
```

Note: Setting `HBASE_DISABLE_HADOOP_CLASSPATH_LOOKUP` does not fix the issue when HBase is in distributed mode. There may be a different warning instead.

## JVM Garbage Collection Logs

<Callout type="info">
Expand Down