[SPARK-21798]: No config to replace deprecated SPARK_CLASSPATH config for launching daemons like History Server

Reverted the previous code change and added the environment variable SPARK_DAEMON_CLASSPATH only for launching daemon processes.

Author: pgandhi

conf/spark-env.sh.template

@@ -52,6 +52,7 @@
 # - SPARK_HISTORY_OPTS, to set config properties only for the history server (e.g. "-Dx=y")
 # - SPARK_SHUFFLE_OPTS, to set config properties only for the external shuffle service (e.g. "-Dx=y")
 # - SPARK_DAEMON_JAVA_OPTS, to set config properties for all daemons (e.g. "-Dx=y")
+# - SPARK_DAEMON_CLASSPATH, to set the classpath for all daemons
 # - SPARK_PUBLIC_DNS, to set the public dns name of the master or workers
 
 # Generic options for the daemons used in the standalone deploy mode

docs/monitoring.md

@@ -61,6 +61,10 @@ The history server can be configured as follows:
     <td><code>SPARK_DAEMON_JAVA_OPTS</code></td>
     <td>JVM options for the history server (default: none).</td>
   </tr>
+  <tr>
+    <td><code>SPARK_DAEMON_CLASSPATH</code></td>
+    <td>Classpath for the history server (default: none).</td>
+  </tr>
   <tr>
     <td><code>SPARK_PUBLIC_DNS</code></td>
     <td>

docs/running-on-mesos.md

@@ -160,6 +160,8 @@ If you like to run the `MesosClusterDispatcher` with Marathon, you need to run t
 The `MesosClusterDispatcher` also supports writing recovery state into Zookeeper. This will allow the `MesosClusterDispatcher` to be able to recover all submitted and running containers on relaunch.   In order to enable this recovery mode, you can set SPARK_DAEMON_JAVA_OPTS in spark-env by configuring `spark.deploy.recoveryMode` and related spark.deploy.zookeeper.* configurations.
 For more information about these configurations please refer to the configurations [doc](configurations.html#deploy).
 
+You can also specify any additional jars required by the `MesosClusterDispatcher` in the classpath by setting the environment variable SPARK_DAEMON_CLASSPATH in spark-env.
+
 From the client, you can submit a job to Mesos cluster by running `spark-submit` and specifying the master URL
 to the URL of the `MesosClusterDispatcher` (e.g: mesos://dispatcher:7077). You can view driver statuses on the
 Spark cluster Web UI.

docs/spark-standalone.md

@@ -149,6 +149,10 @@ You can optionally configure the cluster further by setting environment variable
     <td><code>SPARK_DAEMON_JAVA_OPTS</code></td>
     <td>JVM options for the Spark master and worker daemons themselves in the form "-Dx=y" (default: none).</td>
   </tr>
+  <tr>
+    <td><code>SPARK_DAEMON_CLASSPATH</code></td>
+    <td>Classpath for the Spark master and worker daemons themselves (default: none).</td>
+  </tr>
   <tr>
     <td><code>SPARK_PUBLIC_DNS</code></td>
     <td>The public DNS name of the Spark master and workers (default: none).</td>

launcher/src/main/java/org/apache/spark/launcher/AbstractCommandBuilder.java

@@ -136,8 +136,7 @@ List<String> buildClassPath(String appClassPath) throws IOException {
 
     Set<String> cp = new LinkedHashSet<>();
     addToClassPath(cp, appClassPath);
-    addToClassPath(cp, getenv("SPARK_DAEMON_CLASSPATH"));
-    
+
     addToClassPath(cp, getConfDir());
 
     boolean prependClasses = !isEmpty(getenv("SPARK_PREPEND_CLASSES"));

launcher/src/main/java/org/apache/spark/launcher/SparkClassCommandBuilder.java

@@ -53,16 +53,19 @@ public List<String> buildCommand(Map<String, String> env)
       case "org.apache.spark.deploy.master.Master":
         javaOptsKeys.add("SPARK_DAEMON_JAVA_OPTS");
         javaOptsKeys.add("SPARK_MASTER_OPTS");
+        extraClassPath = getenv("SPARK_DAEMON_CLASSPATH");
         memKey = "SPARK_DAEMON_MEMORY";
         break;
       case "org.apache.spark.deploy.worker.Worker":
         javaOptsKeys.add("SPARK_DAEMON_JAVA_OPTS");
         javaOptsKeys.add("SPARK_WORKER_OPTS");
+        extraClassPath = getenv("SPARK_DAEMON_CLASSPATH");
         memKey = "SPARK_DAEMON_MEMORY";
         break;
       case "org.apache.spark.deploy.history.HistoryServer":
         javaOptsKeys.add("SPARK_DAEMON_JAVA_OPTS");
         javaOptsKeys.add("SPARK_HISTORY_OPTS");
+        extraClassPath = getenv("SPARK_DAEMON_CLASSPATH");
         memKey = "SPARK_DAEMON_MEMORY";
         break;
       case "org.apache.spark.executor.CoarseGrainedExecutorBackend":
@@ -77,11 +80,13 @@ public List<String> buildCommand(Map<String, String> env)
         break;
       case "org.apache.spark.deploy.mesos.MesosClusterDispatcher":
         javaOptsKeys.add("SPARK_DAEMON_JAVA_OPTS");
+        extraClassPath = getenv("SPARK_DAEMON_CLASSPATH");
         break;
       case "org.apache.spark.deploy.ExternalShuffleService":
       case "org.apache.spark.deploy.mesos.MesosExternalShuffleService":
         javaOptsKeys.add("SPARK_DAEMON_JAVA_OPTS");
         javaOptsKeys.add("SPARK_SHUFFLE_OPTS");
+        extraClassPath = getenv("SPARK_DAEMON_CLASSPATH");
         memKey = "SPARK_DAEMON_MEMORY";
         break;
       default: