Copilot commented on code in PR #8029: URL: https://github.com/apache/hbase/pull/8029#discussion_r3046216801
########## hbase-website/app/pages/_docs/docs/_mdx/(multi-page)/troubleshooting.mdx: ########## @@ -55,6 +55,26 @@ 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 running `bin/start-hbase.sh`. For example, you may see the following when starting HBase on your machine: + +``` +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:/Users/kgeiszler/.m2/repository/org/apache/logging/log4j/log4j-slf4j-impl/2.25.3/log4j-slf4j-impl-2.25.3.jar!/org/slf4j/impl/StaticLoggerBinder.class] Review Comment: This example output includes a specific contributor username/path (`/Users/kgeiszler/...`). To avoid embedding personal identifiers and to make the example more broadly applicable, consider replacing it with a placeholder like `$HOME/.m2/...` (and optionally eliding version numbers). ```suggestion SLF4J: Found binding in [jar:file:$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] ``` ########## hbase-website/app/pages/_docs/docs/_mdx/(multi-page)/troubleshooting.mdx: ########## @@ -55,6 +55,26 @@ 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 running `bin/start-hbase.sh`. For example, you may see the following when starting HBase on your machine: + +``` +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:/Users/kgeiszler/.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" +``` + Review Comment: Setting `HBASE_DISABLE_HADOOP_CLASSPATH_LOOKUP=true` disables the `bin/hbase` script's Hadoop discovery. If the user is running an HBase assembly that does *not* bundle Hadoop jars and they haven't set `HADOOP_HOME`, `bin/hbase` will exit with “Installation does not contain Hadoop...”. Consider adding a brief note here about this caveat and the alternatives (set `HADOOP_HOME` to the intended Hadoop install or use an assembly that includes Hadoop). ```suggestion Note that setting `HBASE_DISABLE_HADOOP_CLASSPATH_LOOKUP=true` also disables the `bin/hbase` script's automatic Hadoop discovery. If you are using an HBase assembly that does not bundle Hadoop jars, make sure `HADOOP_HOME` points to the Hadoop installation you want to use, or use an HBase assembly that includes Hadoop. Otherwise, `bin/hbase` may exit with an error such as `Installation does not contain Hadoop...`. ``` ########## hbase-website/app/pages/_docs/docs/_mdx/(multi-page)/troubleshooting.mdx: ########## @@ -55,6 +55,26 @@ 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 running `bin/start-hbase.sh`. For example, you may see the following when starting HBase on your machine: + +``` +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:/Users/kgeiszler/.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] +``` Review Comment: The SLF4J warning snippet is console output; elsewhere in this doc similar output blocks use an explicit language (e.g., ```text). Consider changing this fence to ```text for consistent rendering/syntax highlighting. -- This is an automated message from the Apache Git Service. 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