...

Question: How do I provide my own label and icon for the custom action in UI?

In Ambari UI, add your component action to the App.HostComponentActionMap object with custom icon and name. Ex: REBALANCEHDFS.

Question: How do I provide custom UI side logic for the action, to show or enable the action?

 

Configuration

Configuration files for a service should be placed by default in the configuration folder.
If a different named folder has to be used, the <configuration-dir> element can be used in metainfo.xml to point to that folder.

...

You can read more about the widgets descriptor in the Enhanced Service Dashboard page.

Define Stack

A stack is a versioned collection of services. Each stack is a folder is defined in ambari-server/src/main/resources/stacks source. Once installed, these stack definitions are available on the ambari-server machine at /var/lib/ambari-server/resources/stacks.

Each stack folder contains one sub-folder per version of the stack. Some of these stack-versions are active while some are not. Each stack-version includes services which are either referenced from common-services, or defined inside the stack-version's services folder. 

Image Added

Example: HDP stack. HDP-2.4 stack version.

Stack-Version Descriptor

Each stack-version should provide a metainfo.xml (Example: HDP-2.3, HDP-2.4) descriptor file which describes the following about this stack-version:

<metainfo>
    <versions>
	  <active>true</active>
    </versions>
    <extends>2.3</extends>
    <minJdk>1.7</minJdk>
    <maxJdk>1.8</maxJdk>
</metainfo>

• versions/active - Whether this stack-version is still available for install. If not available, this version will not show up in UI during install.
• extends - The stack-version in this stack that is being extended. Extended stack-versions inherit services along with almost all aspects of the parent stack-version.
• minJdk - Minimum JDK with which this stack-version is supported. Users are warned during installer wizard if the JDK used by Ambari is lower than this version.
• maxJdk - Maximum JDK with which this stack-version is supported. Users are warned during installer wizard if the JDK used by Ambari is greater than this version.

Services

Each stack-version includes services which are either referenced from common-services, or defined inside the stack-version's services folder. 

Command Order

Repositories

...