revert [SPARK-3067] JobProgressPage could not show Fair Scheduler Poo…

…ls section sometimes

core/src/main/scala/org/apache/spark/SparkContext.scala

@@ -223,7 +223,26 @@ class SparkContext(config: SparkConf) extends Logging {
   private[spark] val ui = new SparkUI(this)
 
   /** A default Hadoop Configuration for the Hadoop code (e.g. file systems) that we reuse. */
-  val hadoopConfiguration = SparkHadoopUtil.get.newConfiguration(conf)
+  val hadoopConfiguration: Configuration = {
+    val hadoopConf = SparkHadoopUtil.get.newConfiguration()
+    // Explicitly check for S3 environment variables
+    if (System.getenv("AWS_ACCESS_KEY_ID") != null &&
+        System.getenv("AWS_SECRET_ACCESS_KEY") != null) {
+      hadoopConf.set("fs.s3.awsAccessKeyId", System.getenv("AWS_ACCESS_KEY_ID"))
+      hadoopConf.set("fs.s3n.awsAccessKeyId", System.getenv("AWS_ACCESS_KEY_ID"))
+      hadoopConf.set("fs.s3.awsSecretAccessKey", System.getenv("AWS_SECRET_ACCESS_KEY"))
+      hadoopConf.set("fs.s3n.awsSecretAccessKey", System.getenv("AWS_SECRET_ACCESS_KEY"))
+    }
+    // Copy any "spark.hadoop.foo=bar" system properties into conf as "foo=bar"
+    conf.getAll.foreach { case (key, value) =>
+      if (key.startsWith("spark.hadoop.")) {
+        hadoopConf.set(key.substring("spark.hadoop.".length), value)
+      }
+    }
+    val bufferSize = conf.get("spark.buffer.size", "65536")
+    hadoopConf.set("io.file.buffer.size", bufferSize)
+    hadoopConf
+  }
 
   // Optionally log Spark events
   private[spark] val eventLogger: Option[EventLoggingListener] = {