YARN-3187. Documentation of Capacity Scheduler Queue mapping based on user or group. Contributed by Gururaj Shetty

(cherry picked from commit a380643d2044a4974e379965f65066df2055d003)

hadoop-yarn-project/CHANGES.txt

@@ -327,6 +327,9 @@ Release 2.7.0 - UNRELEASED
     YARN-3296. Mark ResourceCalculatorProcessTree class as Public for configurable
     resource monitoring. (Hitesh Shah via junping_du)
 
+    YARN-3187. Documentation of Capacity Scheduler Queue mapping based on user
+    or group. (Gururaj Shetty via jianhe)
+
   OPTIMIZATIONS
 
     YARN-2990. FairScheduler's delay-scheduling always waits for node-local and 

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/CapacityScheduler.md

@@ -69,6 +69,8 @@ The `CapacityScheduler` supports the following features:
 
 * **Resource-based Scheduling** - Support for resource-intensive applications, where-in a application can optionally specify higher resource-requirements than the default, there-by accomodating applications with differing resource requirements. Currently, *memory* is the the resource requirement supported.
 
+* **Queue Mapping based on User or Group** - This feature allows users to map a job to a specific queue based on the user or group.
+
 Configuration
 -------------
 
@@ -151,6 +153,30 @@ Configuration
 
 **Note:** An *ACL* is of the form *user1*, *user2spacegroup1*, *group2*. The special value of * implies *anyone*. The special value of *space* implies *no one*. The default is * for the root queue if not specified.
 
+  * Queue Mapping based on User or Group
+
+  The `CapacityScheduler` supports the following parameters to configure the queue mapping based on user or group:
+
+| Property | Description |
+|:---- |:---- |
+| `yarn.scheduler.capacity.queue-mappings` | This configuration specifies the mapping of user or group to aspecific queue. You can map a single user or a list of users to queues. Syntax: `[u or g]:[name]:[queue_name][,next_mapping]*`. Here, *u or g* indicates whether the mapping is for a user or group. The value is *u* for user and *g* for group. *name* indicates the user name or group name. To specify the user who has submitted the application, %user can be used. *queue_name* indicates the queue name for which the application has to be mapped. To specify queue name same as user name, *%user* can be used. To specify queue name same as the name of the primary group for which the user belongs to, *%primary_group* can be used.|
+| `yarn.scheduler.capacity.queue-mappings-override.enable` | This function is used to specify whether the user specified queues can be overridden. This is a Boolean value and the default value is *false*. |
+
+Example:
+
+```
+ <property>
+   <name>yarn.scheduler.capacity.queue-mappings</name>
+   <value>u:user1:queue1,g:group1:queue2,u:%user:%user,u:user2:%primary_group</value>
+   <description>
+     Here, <user1> is mapped to <queue1>, <group1> is mapped to <queue2>, 
+     maps users to queues with the same name as user, <user2> is mapped 
+     to queue name same as <primary group> respectively. The mappings will be 
+     evaluated from left to right, and the first valid mapping will be used.
+   </description>
+ </property>
+```
+
 ###Other Properties
 
   * Resource Calculator