Third-party Under Storage Extensions

This page is intended for users of under storage extensions. Please look at developing extensions for an extension development guide.

Alluxio can be extended with the addition of under storage modules at runtime. Under storage extensions (built as JARs) can be included at a specific location to be picked up by core Alluxio without the need to restart any running processes. Adding new under storage connectors to Alluxio can be used to enable Alluxio to work with new storage systems which may not have existing support.

List of Extensions

Following is a list of under storage extension projects:

• S3N
• GlusterFS
• OBS
• SSH UFS

Managing Extensions

Extension JARs are picked up from the extensions directory configured using the property alluxio.extensions.dir (default: ${alluxio-home}/extensions). The extensions command line utility manages distribution of extension JARs across an Alluxio cluster. In environments where the CLI is not applicable (see limitations below), place the JAR in the extensions directory. For example, when running in containers, build a custom image with extension binaries in the appropriate location.

Command Line Utility

A command line utility is provided to aid extension manangement.

$ ./bin/alluxio extensions
Usage: alluxio extensions [generic options]
     [install <URI>]
     [ls]
     [uninstall <JAR>]

Install

The install command copies the provided JAR to Alluxio servers listed in conf/masters and conf/workers using rsync and ssh. However, these tools may not be available in all environments. In such a scenario, use other more suitable tools to place the JAR at the location specified in the property alluxio.extensions.dir on Alluxio servers.

List

To list the installed extensions on any given host running the Alluxio processes, use the ls command. The utility lists any installed extensions by scanning the local extensions directory.

Uninstall

The uninstall command works in a similar manner to install using hosts specified in conf/masters and conf/workers. Remove the extensions manually from Alluxio servers in case some hosts are not reachable from the host executing the command.

Installing from a Maven Coordinate

To install an extension from maven, download the JAR first and then install as follows:

$ mvn dependency:get -DremoteRepositories=http://repo1.maven.org/maven2/ \ 
  -DgroupId=<extension-group> -DartifactId=<extension-artifact> \ 
  -Dversion=<version> -Dtransitive=false -Ddest=<extension>.jar
$ ./bin/alluxio extensions install <extension.jar>

Validation

Once the extension JAR has been distributed, you should be able to mount your under storage using the Alluxio CLI as follows:

$ ./bin/alluxio fs mount /my-storage <scheme>://<path>/ --option <key>=<value>

where, <key>=<value> can be replaced with any required configuration for the under storage.

To run sanity tests execute:

$ ./bin/alluxio runTests --directory /my-storage