[SPARK-2147 / 2161] Show removed executors on the UI

This PR includes two changes
- **[SPARK-2147]** When an application finishes cleanly (i.e. `sc.stop()` is called), all of its executors used to disappear from the Master UI. This no longer happens.
- **[SPARK-2161]** This adds a "Removed Executors" table to Master UI, so the user can find out why their executors died from the logs, for instance. The equivalent table already existed in the Worker UI, but was hidden because of a bug (the comment `//scalastyle:off` disconnected the `Seq[Node]` that represents the HTML for table).

This should go into 1.0.1 if possible.

Author: Andrew Or <andrewor14@gmail.com>

Closes #1102 from andrewor14/remember-removed-executors and squashes the following commits:

2e2298f [Andrew Or] Add hash code method to ExecutorInfo (minor)
abd72e0 [Andrew Or] Merge branch 'master' of github.com:apache/spark into remember-removed-executors
792f992 [Andrew Or] Add missing equals method in ExecutorInfo
3390b49 [Andrew Or] Add executor state column to WorkerPage
161f8a2 [Andrew Or] Display finished executors table (fix bug)
fbb65b8 [Andrew Or] Removed unused method
c89bb6e [Andrew Or] Add table for removed executors in MasterWebUI
fe47402 [Andrew Or] Show exited executors on the Master UI

4 files changed, 107 insertions, 87 deletions

diff --git a/core/src/main/scala/org/apache/spark/deploy/master/ApplicationInfo.scala b/core/src/main/scala/org/apache/spark/deploy/master/ApplicationInfo.scala
index 46b9f4dc7d..72d0589689 100644
--- a/core/src/main/scala/org/apache/spark/deploy/master/ApplicationInfo.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/master/ApplicationInfo.scala
@@ -20,6 +20,7 @@ package org.apache.spark.deploy.master
 import java.util.Date
 
 import scala.collection.mutable
+import scala.collection.mutable.ArrayBuffer
 
 import akka.actor.ActorRef
 
@@ -36,6 +37,7 @@ private[spark] class ApplicationInfo(
 
   @transient var state: ApplicationState.Value = _
   @transient var executors: mutable.HashMap[Int, ExecutorInfo] = _
+  @transient var removedExecutors: ArrayBuffer[ExecutorInfo] = _
   @transient var coresGranted: Int = _
   @transient var endTime: Long = _
   @transient var appSource: ApplicationSource = _
@@ -51,6 +53,7 @@ private[spark] class ApplicationInfo(
     endTime = -1L
     appSource = new ApplicationSource(this)
     nextExecutorId = 0
+    removedExecutors = new ArrayBuffer[ExecutorInfo]
   }
 
   private def newExecutorId(useID: Option[Int] = None): Int = {
@@ -74,6 +77,7 @@ private[spark] class ApplicationInfo(
 
   def removeExecutor(exec: ExecutorInfo) {
     if (executors.contains(exec.id)) {
+      removedExecutors += executors(exec.id)
       executors -= exec.id
       coresGranted -= exec.cores
     }
diff --git a/core/src/main/scala/org/apache/spark/deploy/master/ExecutorInfo.scala b/core/src/main/scala/org/apache/spark/deploy/master/ExecutorInfo.scala
index 76db61dd61..d417070c51 100644
--- a/core/src/main/scala/org/apache/spark/deploy/master/ExecutorInfo.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/master/ExecutorInfo.scala
@@ -34,4 +34,19 @@ private[spark] class ExecutorInfo(
   }
 
   def fullId: String = application.id + "/" + id
+
+  override def equals(other: Any): Boolean = {
+    other match {
+      case info: ExecutorInfo =>
+        fullId == info.fullId &&
+        worker.id == info.worker.id &&
+        cores == info.cores &&
+        memory == info.memory
+      case _ => false
+    }
+  }
+
+  override def toString: String = fullId
+
+  override def hashCode: Int = toString.hashCode()
 }
diff --git a/core/src/main/scala/org/apache/spark/deploy/master/ui/ApplicationPage.scala b/core/src/main/scala/org/apache/spark/deploy/master/ui/ApplicationPage.scala
index b5cd4d2ea9..34fa1429c8 100644
--- a/core/src/main/scala/org/apache/spark/deploy/master/ui/ApplicationPage.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/master/ui/ApplicationPage.scala
@@ -25,7 +25,7 @@ import scala.xml.Node
 import akka.pattern.ask
 import org.json4s.JValue
 
-import org.apache.spark.deploy.JsonProtocol
+import org.apache.spark.deploy.{ExecutorState, JsonProtocol}
 import org.apache.spark.deploy.DeployMessages.{MasterStateResponse, RequestMasterState}
 import org.apache.spark.deploy.master.ExecutorInfo
 import org.apache.spark.ui.{WebUIPage, UIUtils}
@@ -57,43 +57,55 @@ private[spark] class ApplicationPage(parent: MasterWebUI) extends WebUIPage("app
     })
 
     val executorHeaders = Seq("ExecutorID", "Worker", "Cores", "Memory", "State", "Logs")
-    val executors = app.executors.values.toSeq
-    val executorTable = UIUtils.listingTable(executorHeaders, executorRow, executors)
+    val allExecutors = (app.executors.values ++ app.removedExecutors).toSet.toSeq
+    // This includes executors that are either still running or have exited cleanly
+    val executors = allExecutors.filter { exec =>
+      !ExecutorState.isFinished(exec.state) || exec.state == ExecutorState.EXITED
+    }
+    val removedExecutors = allExecutors.diff(executors)
+    val executorsTable = UIUtils.listingTable(executorHeaders, executorRow, executors)
+    val removedExecutorsTable = UIUtils.listingTable(executorHeaders, executorRow, removedExecutors)
 
     val content =
-        <div class="row-fluid">
-          <div class="span12">
-            <ul class="unstyled">
-              <li><strong>ID:</strong> {app.id}</li>
-              <li><strong>Name:</strong> {app.desc.name}</li>
-              <li><strong>User:</strong> {app.desc.user}</li>
-              <li><strong>Cores:</strong>
-                {
-                if (app.desc.maxCores.isEmpty) {
-                  "Unlimited (%s granted)".format(app.coresGranted)
-                } else {
-                  "%s (%s granted, %s left)".format(
-                    app.desc.maxCores.get, app.coresGranted, app.coresLeft)
-                }
-                }
-              </li>
-              <li>
-                <strong>Executor Memory:</strong>
-                {Utils.megabytesToString(app.desc.memoryPerSlave)}
-              </li>
-              <li><strong>Submit Date:</strong> {app.submitDate}</li>
-              <li><strong>State:</strong> {app.state}</li>
-              <li><strong><a href={app.desc.appUiUrl}>Application Detail UI</a></strong></li>
-            </ul>
-          </div>
+      <div class="row-fluid">
+        <div class="span12">
+          <ul class="unstyled">
+            <li><strong>ID:</strong> {app.id}</li>
+            <li><strong>Name:</strong> {app.desc.name}</li>
+            <li><strong>User:</strong> {app.desc.user}</li>
+            <li><strong>Cores:</strong>
+            {
+              if (app.desc.maxCores.isEmpty) {
+                "Unlimited (%s granted)".format(app.coresGranted)
+              } else {
+                "%s (%s granted, %s left)".format(
+                  app.desc.maxCores.get, app.coresGranted, app.coresLeft)
+              }
+            }
+            </li>
+            <li>
+              <strong>Executor Memory:</strong>
+              {Utils.megabytesToString(app.desc.memoryPerSlave)}
+            </li>
+            <li><strong>Submit Date:</strong> {app.submitDate}</li>
+            <li><strong>State:</strong> {app.state}</li>
+            <li><strong><a href={app.desc.appUiUrl}>Application Detail UI</a></strong></li>
+          </ul>
         </div>
+      </div>
 
-        <div class="row-fluid"> <!-- Executors -->
-          <div class="span12">
-            <h4> Executor Summary </h4>
-            {executorTable}
-          </div>
-        </div>;
+      <div class="row-fluid"> <!-- Executors -->
+        <div class="span12">
+          <h4> Executor Summary </h4>
+          {executorsTable}
+          {
+            if (removedExecutors.nonEmpty) {
+              <h4> Removed Executors </h4> ++
+              removedExecutorsTable
+            }
+          }
+        </div>
+      </div>;
     UIUtils.basicSparkPage(content, "Application: " + app.desc.name)
   }
 
diff --git a/core/src/main/scala/org/apache/spark/deploy/worker/ui/WorkerPage.scala b/core/src/main/scala/org/apache/spark/deploy/worker/ui/WorkerPage.scala
index d4513118ce..327b905032 100644
--- a/core/src/main/scala/org/apache/spark/deploy/worker/ui/WorkerPage.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/worker/ui/WorkerPage.scala
@@ -46,74 +46,62 @@ private[spark] class WorkerPage(parent: WorkerWebUI) extends WebUIPage("") {
     val stateFuture = (workerActor ? RequestWorkerState)(timeout).mapTo[WorkerStateResponse]
     val workerState = Await.result(stateFuture, timeout)
 
-    val executorHeaders = Seq("ExecutorID", "Cores", "Memory", "Job Details", "Logs")
+    val executorHeaders = Seq("ExecutorID", "Cores", "State", "Memory", "Job Details", "Logs")
+    val runningExecutors = workerState.executors
     val runningExecutorTable =
-      UIUtils.listingTable(executorHeaders, executorRow, workerState.executors)
+      UIUtils.listingTable(executorHeaders, executorRow, runningExecutors)
+    val finishedExecutors = workerState.finishedExecutors
     val finishedExecutorTable =
-      UIUtils.listingTable(executorHeaders, executorRow, workerState.finishedExecutors)
+      UIUtils.listingTable(executorHeaders, executorRow, finishedExecutors)
 
     val driverHeaders = Seq("DriverID", "Main Class", "State", "Cores", "Memory", "Logs", "Notes")
     val runningDrivers = workerState.drivers.sortBy(_.driverId).reverse
     val runningDriverTable = UIUtils.listingTable(driverHeaders, driverRow, runningDrivers)
     val finishedDrivers = workerState.finishedDrivers.sortBy(_.driverId).reverse
-    def finishedDriverTable = UIUtils.listingTable(driverHeaders, driverRow, finishedDrivers)
+    val finishedDriverTable = UIUtils.listingTable(driverHeaders, driverRow, finishedDrivers)
 
     // For now we only show driver information if the user has submitted drivers to the cluster.
     // This is until we integrate the notion of drivers and applications in the UI.
-    def hasDrivers = runningDrivers.length > 0 || finishedDrivers.length > 0
 
     val content =
-        <div class="row-fluid"> <!-- Worker Details -->
-          <div class="span12">
-            <ul class="unstyled">
-              <li><strong>ID:</strong> {workerState.workerId}</li>
-              <li><strong>
-                Master URL:</strong> {workerState.masterUrl}
-              </li>
-              <li><strong>Cores:</strong> {workerState.cores} ({workerState.coresUsed} Used)</li>
-              <li><strong>Memory:</strong> {Utils.megabytesToString(workerState.memory)}
-                ({Utils.megabytesToString(workerState.memoryUsed)} Used)</li>
-            </ul>
-            <p><a href={workerState.masterWebUiUrl}>Back to Master</a></p>
-          </div>
+      <div class="row-fluid"> <!-- Worker Details -->
+        <div class="span12">
+          <ul class="unstyled">
+            <li><strong>ID:</strong> {workerState.workerId}</li>
+            <li><strong>
+              Master URL:</strong> {workerState.masterUrl}
+            </li>
+            <li><strong>Cores:</strong> {workerState.cores} ({workerState.coresUsed} Used)</li>
+            <li><strong>Memory:</strong> {Utils.megabytesToString(workerState.memory)}
+              ({Utils.megabytesToString(workerState.memoryUsed)} Used)</li>
+          </ul>
+          <p><a href={workerState.masterWebUiUrl}>Back to Master</a></p>
         </div>
-
-        <div class="row-fluid"> <!-- Running Executors -->
-          <div class="span12">
-            <h4> Running Executors {workerState.executors.size} </h4>
-            {runningExecutorTable}
-          </div>
-        </div>
-        // scalastyle:off
-        <div>
-          {if (hasDrivers)
-            <div class="row-fluid"> <!-- Running Drivers -->
-              <div class="span12">
-                <h4> Running Drivers {workerState.drivers.size} </h4>
-                {runningDriverTable}
-              </div>
-            </div>
+      </div>
+      <div class="row-fluid"> <!-- Executors and Drivers -->
+        <div class="span12">
+          <h4> Running Executors ({runningExecutors.size}) </h4>
+          {runningExecutorTable}
+          {
+            if (runningDrivers.nonEmpty) {
+              <h4> Running Drivers ({runningDrivers.size}) </h4> ++
+              runningDriverTable
+            }
           }
-        </div>
-
-        <div class="row-fluid"> <!-- Finished Executors  -->
-          <div class="span12">
-            <h4> Finished Executors </h4>
-            {finishedExecutorTable}
-          </div>
-        </div>
-
-        <div>
-          {if (hasDrivers)
-            <div class="row-fluid"> <!-- Finished Drivers  -->
-              <div class="span12">
-                <h4> Finished Drivers </h4>
-                {finishedDriverTable}
-              </div>
-            </div>
+          {
+            if (finishedExecutors.nonEmpty) {
+              <h4>Finished Executors ({finishedExecutors.size}) </h4> ++
+              finishedExecutorTable
+            }
           }
-        </div>;
-    // scalastyle:on
+          {
+            if (finishedDrivers.nonEmpty) {
+              <h4> Finished Drivers ({finishedDrivers.size}) </h4> ++
+              finishedDriverTable
+            }
+          }
+        </div>
+      </div>;
     UIUtils.basicSparkPage(content, "Spark Worker at %s:%s".format(
       workerState.host, workerState.port))
   }
@@ -122,6 +110,7 @@ private[spark] class WorkerPage(parent: WorkerWebUI) extends WebUIPage("") {
     <tr>
       <td>{executor.execId}</td>
       <td>{executor.cores}</td>
+      <td>{executor.state}</td>
       <td sorttable_customkey={executor.memory.toString}>
         {Utils.megabytesToString(executor.memory)}
       </td>