Use conf.getenv to read SPARK_PUBLIC_DNS

Author: JoshRosen

core/src/main/scala/org/apache/spark/deploy/master/Master.scala

@@ -96,7 +96,7 @@ private[spark] class Master(
   val webUi = new MasterWebUI(this, webUiPort)
 
   val masterPublicAddress = {
-    val envVar = System.getenv("SPARK_PUBLIC_DNS")
+    val envVar = conf.getenv("SPARK_PUBLIC_DNS")
     if (envVar != null) envVar else host
   }
 

core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala

@@ -121,7 +121,7 @@ private[spark] class Worker(
   val shuffleService = new StandaloneWorkerShuffleService(conf, securityMgr)
 
   val publicAddress = {
-    val envVar = System.getenv("SPARK_PUBLIC_DNS")
+    val envVar = conf.getenv("SPARK_PUBLIC_DNS")
     if (envVar != null) envVar else host
   }
   var webUi: WorkerWebUI = null

core/src/main/scala/org/apache/spark/ui/WebUI.scala

@@ -47,7 +47,7 @@ private[spark] abstract class WebUI(
   protected val handlers = ArrayBuffer[ServletContextHandler]()
   protected var serverInfo: Option[ServerInfo] = None
   protected val localHostName = Utils.localHostName()
-  protected val publicHostName = Option(System.getenv("SPARK_PUBLIC_DNS")).getOrElse(localHostName)
+  protected val publicHostName = Option(conf.getenv("SPARK_PUBLIC_DNS")).getOrElse(localHostName)
   private val className = Utils.getFormattedClassName(this)
 
   def getBasePath: String = basePath