From 9bd81d2c8979c9759d29bc6920181bf6a090dcb3 Mon Sep 17 00:00:00 2001
From: Jim Crist <jcrist@users.noreply.github.com>
Date: Mon, 29 Oct 2018 10:15:28 -0500
Subject: [PATCH] Use NM_HOST to determine hostname (#97)

Some clusters have infiniband enabled, which may get picked up by
`InetAddress` when determining the application-master hostname/IP.
Infiniband is not currently supported by gRPC, so this would result in
failures. Instead of trying to more robustly determine the IP for a
supported network interface, we rely on the `NM_HOST` environment
variable, which is always set and must resolve correctly on all nodes
for hadoop to properly work.
---
 .../java/com/anaconda/skein/ApplicationMaster.java  | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/java/src/main/java/com/anaconda/skein/ApplicationMaster.java b/java/src/main/java/com/anaconda/skein/ApplicationMaster.java
index d2747321..54477902 100644
--- a/java/src/main/java/com/anaconda/skein/ApplicationMaster.java
+++ b/java/src/main/java/com/anaconda/skein/ApplicationMaster.java
@@ -46,8 +46,6 @@
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
-import java.net.InetAddress;
-import java.net.UnknownHostException;
 import java.nio.ByteBuffer;
 import java.security.PrivilegedAction;
 import java.util.ArrayList;
@@ -151,7 +149,7 @@ public void run() {
           }
         });
 
-    LOG.info("gRPC server started, listening on {}", grpcServer.getPort());
+    LOG.info("gRPC server started at {}:{}", hostname, grpcServer.getPort());
   }
 
   private void stopServer() {
@@ -208,7 +206,7 @@ public void run() {
           }
         });
 
-    LOG.info("WebUI server started, listening on {}", ui.getURI().getPort());
+    LOG.info("WebUI server started at {}:{}", hostname, ui.getURI().getPort());
   }
 
   private void stopUI() {
@@ -435,12 +433,6 @@ public void run() throws Exception {
 
     loadApplicationSpec();
 
-    try {
-      hostname = InetAddress.getLocalHost().getHostAddress();
-    } catch (UnknownHostException exc) {
-      fatal("Couldn't determine hostname for appmaster", exc);
-    }
-
     // Create ugi and add original tokens to it
     String userName = System.getenv(Environment.USER.name());
     LOG.info("Running as user {}", userName);
@@ -476,6 +468,7 @@ public void run() throws Exception {
         MAX_EXECUTOR_THREADS,
         true);
 
+    hostname = System.getenv(Environment.NM_HOST.name());
     startServer();
     startUI();