The YARN UI is an Ember based web-app that provides visualization of the applications running on the Apache Hadoop YARN framework.


You can point the UI to custom locations by setting the environment variables in src/main/webapp/config/configs.env.

In order to make the UI running on Ember server (started by yarn start) work with independently running ResouceManager, you need to enable CORS by setting hadoop.http.cross-origin.enabled to true and adding org.apache.hadoop.security.HttpCrossOriginFilterInitializer to hadoop.http.filter.initializers in core-site.xml of the ResourceManager.


All the following commands must be run inside src/main/webapp.


You will need the following things properly installed on your computer.

  • Install Yarn v1.21.1
  • Install Bower v1.8.8
  • Install all dependencies by running yarn install & bower install

Running UI


  • yarn run build (production)
  • Files would be stored in “dist/”

Adding new dependencies

Warning: Do not edit the package.json or bower.json files manually. This could make them out-of-sync with the respective lock or shrinkwrap files.

YARN UI has replaced NPM with Yarn package manager. And hence Yarn would be used to manage dependencies defined in package.json.

  • Please use the Yarn and Bower command-line tools to add new dependencies. And the tool version must be same as those defined in Prerequisites section.
  • Once any dependency is added:
    • If it's in package.json. Make sure that the respective, and only those changes are reflected in yarn.lock file.
    • If it's in bower.json. Make sure that the respective, and only those changes are reflected in bower-shrinkwrap.json file.
  • Commands to add using CLI tools:
    • Yarn: yarn add [package-name]
    • Bower: bower install --save [package-name]

Adding new routes (pages), controllers, components etc.

  • Use ember-cli blueprint generator - Ember CLI

Building with Maven

YARN-6278 added yarn-ui profile to pom.xml leveraging frontend-maven-plugin which automatically installs Node.js and Yarn locally under target/webapp directory. After building yarn-ui by mvn package -Pyarn-ui, you can reuse the locally installed Node.js and Yarn instead of manually installing them.

$ mvn package -Pyarn-ui
$ export PATH=$PWD/target/webapp/node:$PATH
$ export YARNJS=$PWD/target/webapp/node/yarn/dist/bin/yarn.js
$ cd src/main/webapp/
$ node $YARNJS install
$ node node_modules/.bin/bower install
$ node $YARNJS start