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To customize categories and ordering of configurations in UI, the following files have to be updated.
Create Category -  Update the ambari-web/app/models/stack_service.js file to add your own service, along with your new categories.
Use Category - To place configs inside  a defined category, and specify an order in which configs are placed, add configs to ambari-web/app/data/HDP2/site_properties.js file. In this file one can specify the category to use, and the index where a config should be placed. The stack folders in ambari-web/app/data are hierarchical and inherit from previous versions.

UI - Enhanced Configs

The Enhanced Configs feature makes it possible for service providers to customize their service's configs to a great deal and determine which configs are prominently shown to user without making any UI code changes. Customization includes providing a service friendly layout, better controls (sliders, combos, lists, toggles, spinners, etc.), better validation (minimum, maximum, enums), automatic unit conversion (MB, GB, seconds, milliseconds, etc.), configuration dependencies and improved dynamic recommendations of default values.

 A service provider can accomplish all the above just by changing their service definition in the stacks/ folder.

Read more in the Enhanced Configs  page

Alerts

Kerberos

Metrics

Widgets

Define Stack

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