YARN-3623. Add a config to indicate the Timeline Service version. Contributed by Xuan Gong.

hadoop-yarn-project/CHANGES.txt

@@ -271,6 +271,9 @@ Release 2.8.0 - UNRELEASED
 
     YARN-4349. Support CallerContext in YARN. (wtan via jianhe)
 
+    YARN-3623. Add a new config to indicate the Timeline Service version. 
+    (Xuan Gong via junping_du)
+
   IMPROVEMENTS
 
     YARN-644. Basic null check is not performed on passed in arguments before

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java

@@ -1538,6 +1538,9 @@ public class YarnConfiguration extends Configuration {
   public static final String TIMELINE_SERVICE_PREFIX =
       YARN_PREFIX + "timeline-service.";
 
+  public static final String TIMELINE_SERVICE_VERSION = TIMELINE_SERVICE_PREFIX
+      + "version";
+  public static final float DEFAULT_TIMELINE_SERVICE_VERSION = 1.0f;
   /**
    * Comma seperated list of names for UIs hosted in the timeline server
    * (For pluggable UIs).

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml

@@ -1765,6 +1765,20 @@
 
   <!-- Timeline Service Configuration -->
 
+  <property>
+    <description>Indicate what is the current version of the running
+    timeline service. For example, if "yarn.timeline-service.version" is 1.5,
+    and "yarn.timeline-service.enabled" is true, it means the cluster will and
+    should bring up the timeline service v.1.5 (and nothing else).
+    On the client side, if the client uses the same version of timeline service,
+    it should succeed. If the client chooses to use a smaller version in spite of this,
+    then depending on how robust the compatibility story is between versions,
+    the results may vary.
+    </description>
+    <name>yarn.timeline-service.version</name>
+    <value>1.0f</value>
+  </property>
+
   <property>
     <description>Indicate to clients whether timeline service is enabled or not.
     If enabled, clients will put entities and events to the timeline server.