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We recommend using IntelliJ IDEA to contribute to Alluxio. Eclipse can also be used. Instructions for setting up both IDEs can be found below.

IntelliJ IDEA

To use IntelliJ IDEA to contribute to Alluxio, simply open IntelliJ and select “Import existing project”. Then select the “Maven” project type from the IntelliJ dialog. IntelliJ’s default configuration works without any modifications.

Enable the developer Maven profile

After successfully importing your local Alluxio repo into IntelliJ, you may need to add the Maven profile ‘developer’ in order to avoid import errors.

You can do this by going to

View > Tool Windows > Maven

In the Maven panel, find the “developer” profile and check the box next to it in the “Profiles” list.

Generated sources

Some source files in Alluxio are generated from templates or compiled from other languages.

  1. gRPC and ProtoBuf definitions are compiled into Java source files and generated files are located in common/transport/target/generated-sources/protobuf/.
  2. Compile time project constants are defined in dora/core/common/src/main/java-templates/ and compiled to dora/core/common/target/generated-sources/java-templates/.

You will need to mark these directories as “Generated Sources Root” for IntelliJ to resolve the source files. Alternatively, you can let IntelliJ generate them and mark the directories automatically by running “Generate Sources and Update Folders for All Projects”. You can find the button to trigger the generation at the top of the Maven panel, or you can search for this action from the Navigate > Search Everywhere dialog.

See also Modifying a gRPC definition and Modifying a Protocol Buffer Message.

Run Alluxio processes within IntelliJ IDEA

Start a single master Alluxio cluster
  1. Run dev/intellij/
  2. Restart IntelliJ IDEA
  3. Edit conf/ to contain these configurations
  4. Edit conf/ to print log in console Replace the log4j.rootLogger configuration with
     log4j.rootLogger=INFO, ${alluxio.logger.type}, ${alluxio.remote.logger.type}, stdout

    and add the following configurations

     log4j.appender.stdout.layout.ConversionPattern=%d{ISO8601} %-5p %c{2} (%F:%M(%L)) - %m%n
  5. Format the Alluxio master by running bin/alluxio journal format
  6. In Intellij, start Alluxio master process by selecting Run > Run > AlluxioMaster
  7. In Intellij, start Alluxio worker process by selecting Run > Run > AlluxioWorker
  8. Verify the Alluxio cluster is up.
Start a High Availability (HA) Alluxio cluster
  1. Create journal directories for the masters
     $ mkdir -p /tmp/alluxio-tmp/alluxio-0/journal
     $ mkdir -p /tmp/alluxio-tmp/alluxio-1/journal
     $ mkdir -p /tmp/alluxio-tmp/alluxio-2/journal

    These directories are defined in the run configurations, i.e. alluxio/dev/intellij/runConfigurations/AlluxioMaster_0.xml.

    Note: If the journal folders exist, and you want to apply a new HA cluster, you should clear files in the journal folders first.

  2. Run dev/intellij/
  3. Restart IntelliJ IDEA
  4. Edit conf/ to contain these configurations

    The ports are defined in the run configurations.

  5. In Intellij, start the Alluxio master processes by selecting Run > Run > AlluxioMaster-0, Run > Run > AlluxioMaster-1, and Run > Run > AlluxioMaster-2
  6. In Intellij, start the Alluxio worker process by selecting Run > Run > AlluxioWorker
Start an AlluxioFuse process
  1. Start a single master Alluxio cluster or a High Availability cluster in Intellij.
  2. In Intellij, start AlluxioFuse process by selecting Run > Run > AlluxioFuse. This creates a FUSE mount point at /tmp/alluxio-fuse.
  3. Verify the FUSE filesystem is working by running these commands:
     $ touch /tmp/alluxio-fuse/tmp1
     $ ls /tmp/alluxio-fuse
     $ bin/alluxio fs ls /

    You should be able to see the file is created and listed by both ls commands.

Starting multiple processes in IntelliJ at once

IntelliJ is capable of creating groups of processes that all be launched simultaneously. To do so go to Run > Edit Configurations > + > Compound. From there you can create a group of processes that can be launched together using a single Run > Run > command. This can be useful when launching clusters from IntelliJ.


Import the folder into Eclipse. You may also have to add the classpath variable M2_REPO by running:

$ mvn -Declipse.workspace="your Eclipse Workspace" eclipse:configure-workspace

Note: Generated gRPC proto source files are located in alluxio/core/transport/target/generated-sources/protobuf/. You will need to mark the directory as a source folder for Eclipse to resolve the source files.

Maven Targets and Plugins

Before pushing changes or submitting pull requests, we recommend running various maven targets on your local machine to make sure your changes do not break existing behavior.

For these maven commands we’ll assume that your command terminal is located in the root directory of your local copy of the Alluxio repository.



To make sure your code follows our style conventions you may run. Note that this is run any time you run targets such as compile, install, or test.

$ mvn checkstyle:checkstyle


Before submitting the pull-request, run the latest code against the spotbugs Maven plugin to verify no new warnings are introduced.

$ mvn spotbugs:spotbugs


To simply compile the code you can run the following command:

$ mvn clean compile -DskipTests

This will not execute any unit tests but will execute maven plugins such as checkstyle and spotbugs.

To speed up compilation you may use the following command:

$ mvn -T 2C compile -DskipTests -Dmaven.javadoc.skip -Dfindbugs.skip -Dcheckstyle.skip -Dlicense.skip -pl '!webui'

This command will skip many of our checks that are in place to help keep our code neat. We recommend running all checks before committing.

  • -T 2C runs maven with up to 2 threads per CPU core
  • -DskipTests skips running unit and integration tests
  • -Dmaven.javadoc.skip skips javadoc generation
  • -Dfindbugs.skip skips findbugs execution
  • -Dcheckstyle.skip skips code-style checking
  • -Dlicense.skip skips checking files for license headers
  • -pl '!webui' skips building the Alluxio UI module. If this module isn’t compiled then the UI cannot be accessed locally.

You may replace the compile target in the above command with any other valid maven target to skip checks as well. The targets compile, verify, and install are typically the most useful.

Creating a Local Install

If you want to test your changes with a compiled version of the repository, you may generate the jars with the Maven install target. The first time Maven executes it will likely need to download many dependencies. Please be patient as the first build may take a while.

$ mvn -T 2C install -DskipTests

After the install target executes, you can follow the instructions at Running Alluxio Locally to start a local cluster.

Unit Tests

Run all unit and integration tests

$ mvn test

This will use the local filesystem as the under storage.

Run a single unit test

$ mvn -Dtest=<AlluxioTestClass>#<testMethod> -DfailIfNoTests=false test

Run unit tests for a specific module

You can execute the maven test command targeting the desired submodule directory. For example, to run tests for HDFS UFS module you would run

$ mvn test -pl underfs/hdfs

Run unit tests for HDFS UFS module with a different Hadoop version

# build and run test on HDFS under storage module for Hadoop 2.7.0
$ mvn test -pl underfs/hdfs -Phadoop-2 -Dhadoop.version=2.7.0
# build and run test on HDFS under storage module for Hadoop 3.0.0
$ mvn test -pl underfs/hdfs -Phadoop-3 -Dhadoop.version=3.0.0

The above unit tests will create a simulated HDFS service with a specific version. To run more comprehensive tests on HDFS under storage using a real and running HDFS deployment:

$ mvn test -pl underfs/hdfs -PufsContractTest -DtestHdfsBaseDir=hdfs://ip:port/alluxio_test

Redirect logs to STDOUT

To have the logs output to STDOUT, append the following arguments to the mvn command

-Dtest.output.redirect=false -Dalluxio.root.logger=DEBUG,CONSOLE


The FUSE tests are ignored if the libfuse library is missing. To run those tests, please install the libraries referenced in the Alluxio FUSE documentation.

Modifying a gRPC definition

Alluxio uses gRPC 1.37.0 for RPC communication between clients and servers. The .proto files defined in core/transport/src/grpc/ are used to auto-generate Java code for calling the RPCs on clients and implementing the RPCs on servers. To regenerate Java code after changing a gRPC definition, you must rebuild alluxio-core-transport module with 'generate' maven profile.

$ mvn clean install -Pgenerate -pl "org.alluxio:alluxio-core-transport"

Modifying a Protocol Buffer Message

Alluxio uses Protocol Buffers 3.19 to read and write journal entries. The .proto files defined in core/transport/src/proto/ are used to auto-generate Java definitions for the protocol buffer messages.

To change one of these messages, first read about updating a message type to make sure your change will not break backwards compatibility. To regenerate Java code after changing a definition, you must rebuild alluxio-core-transport module with the 'generate' maven profile.

$ mvn clean install -Pgenerate -pl "org.alluxio:alluxio-core-transport"