YARN-8027. Setting hostname of docker container breaks for --net=host in docker 1.13. Contributed by Jim Brennan

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/linux/runtime/DockerLinuxContainerRuntime.java

@@ -133,7 +133,8 @@
  *   <li>
  *     {@code YARN_CONTAINER_RUNTIME_DOCKER_CONTAINER_HOSTNAME} sets the
  *     hostname to be used by the Docker container. If not specified, a
- *     hostname will be derived from the container ID.
+ *     hostname will be derived from the container ID.  This variable is
+ *     ignored if the network is 'host' and Registry DNS is not enabled.
  *   </li>
  *   <li>
  *     {@code YARN_CONTAINER_RUNTIME_DOCKER_RUN_PRIVILEGED_CONTAINER}
@@ -785,7 +786,12 @@ public void launchContainer(ContainerRuntimeContext ctx)
         .detachOnRun()
         .setContainerWorkDir(containerWorkDir.toString())
         .setNetworkType(network);
-    setHostname(runCommand, containerIdStr, hostname);
+    // Only add hostname if network is not host or if Registry DNS is enabled.
+    if (!network.equalsIgnoreCase("host") ||
+        conf.getBoolean(RegistryConstants.KEY_DNS_ENABLED,
+            RegistryConstants.DEFAULT_DNS_ENABLED)) {
+      setHostname(runCommand, containerIdStr, hostname);
+    }
     runCommand.setCapabilities(capabilities);
 
     runCommand.addAllReadWriteMountLocations(containerLogDirs);

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/linux/runtime/TestDockerContainerRuntime.java

@@ -25,6 +25,7 @@
 import org.apache.hadoop.fs.FileUtil;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.io.DataOutputBuffer;
+import org.apache.hadoop.registry.client.api.RegistryConstants;
 import org.apache.hadoop.registry.client.binding.RegistryPathUtils;
 import org.apache.hadoop.security.Credentials;
 import org.apache.hadoop.util.Shell;
@@ -202,6 +203,8 @@ public void setup() {
       LOG.info("Could not run id -G command: " + e);
     }
     uidGidPair = uid + ":" + gid;
+    // Prevent gid threshold failures for these tests
+    conf.setInt(YarnConfiguration.NM_DOCKER_USER_REMAPPING_GID_THRESHOLD, 0);
 
     user = "user";
     appId = "app_id";
@@ -340,7 +343,7 @@ public void testDockerContainerLaunch()
     List<String> dockerCommands = Files.readAllLines(Paths.get
             (dockerCommandFile), Charset.forName("UTF-8"));
 
-    int expected = 15;
+    int expected = 14;
     int counter = 0;
     Assert.assertEquals(expected, dockerCommands.size());
     Assert.assertEquals("[docker-command-execution]",
@@ -352,7 +355,6 @@ public void testDockerContainerLaunch()
     Assert.assertEquals("  docker-command=run", dockerCommands.get(counter++));
     Assert.assertEquals("  group-add=" + String.join(",", groups),
         dockerCommands.get(counter++));
-    Assert.assertEquals("  hostname=ctr-id", dockerCommands.get(counter++));
     Assert
         .assertEquals("  image=busybox:latest", dockerCommands.get(counter++));
     Assert.assertEquals(
@@ -390,7 +392,7 @@ public void testContainerLaunchWithUserRemapping()
     List<String> dockerCommands = Files.readAllLines(
         Paths.get(dockerCommandFile), Charset.forName("UTF-8"));
 
-    Assert.assertEquals(15, dockerCommands.size());
+    Assert.assertEquals(14, dockerCommands.size());
     int counter = 0;
     Assert.assertEquals("[docker-command-execution]",
         dockerCommands.get(counter++));
@@ -401,8 +403,6 @@ public void testContainerLaunchWithUserRemapping()
     Assert.assertEquals("  docker-command=run", dockerCommands.get(counter++));
     Assert.assertEquals("  group-add=" + String.join(",", groups),
         dockerCommands.get(counter++));
-    Assert.assertEquals("  hostname=ctr-id",
-        dockerCommands.get(counter++));
     Assert
         .assertEquals("  image=busybox:latest", dockerCommands.get(counter++));
     Assert.assertEquals(
@@ -488,10 +488,7 @@ public void testContainerLaunchWithNetworkingDefaults()
       LOG.info("Caught expected exception: " + e);
     }
 
-    int size = YarnConfiguration
+    String allowedNetwork = "bridge";
-        .DEFAULT_NM_DOCKER_ALLOWED_CONTAINER_NETWORKS.length;
-    String allowedNetwork = YarnConfiguration
-        .DEFAULT_NM_DOCKER_ALLOWED_CONTAINER_NETWORKS[randEngine.nextInt(size)];
     env.put(DockerLinuxContainerRuntime.ENV_DOCKER_CONTAINER_NETWORK,
         allowedNetwork);
     String expectedHostname = "test.hostname";
@@ -542,6 +539,64 @@ public void testContainerLaunchWithNetworkingDefaults()
         dockerCommands.get(counter));
   }
 
+  @Test
+  @SuppressWarnings("unchecked")
+  public void testContainerLaunchWithHostDnsNetwork()
+      throws ContainerExecutionException, IOException,
+      PrivilegedOperationException {
+    // Make it look like Registry DNS is enabled so we can test whether
+    // hostname goes through
+    conf.setBoolean(RegistryConstants.KEY_DNS_ENABLED, true);
+    DockerLinuxContainerRuntime runtime =
+        new DockerLinuxContainerRuntime(mockExecutor, mockCGroupsHandler);
+    runtime.initialize(conf, null);
+
+    String expectedHostname = "test.hostname";
+    env.put(DockerLinuxContainerRuntime.ENV_DOCKER_CONTAINER_HOSTNAME,
+        expectedHostname);
+
+    runtime.launchContainer(builder.build());
+    PrivilegedOperation op = capturePrivilegedOperationAndVerifyArgs();
+    List<String> args = op.getArguments();
+    String dockerCommandFile = args.get(11);
+
+    //This is the expected docker invocation for this case
+    List<String> dockerCommands = Files
+        .readAllLines(Paths.get(dockerCommandFile), Charset.forName("UTF-8"));
+    int expected = 15;
+    int counter = 0;
+    Assert.assertEquals(expected, dockerCommands.size());
+    Assert.assertEquals("[docker-command-execution]",
+        dockerCommands.get(counter++));
+    Assert.assertEquals("  cap-add=SYS_CHROOT,NET_BIND_SERVICE",
+        dockerCommands.get(counter++));
+    Assert.assertEquals("  cap-drop=ALL", dockerCommands.get(counter++));
+    Assert.assertEquals("  detach=true", dockerCommands.get(counter++));
+    Assert.assertEquals("  docker-command=run", dockerCommands.get(counter++));
+    Assert.assertEquals("  group-add=" + String.join(",", groups),
+        dockerCommands.get(counter++));
+    Assert.assertEquals("  hostname=test.hostname",
+        dockerCommands.get(counter++));
+    Assert
+        .assertEquals("  image=busybox:latest", dockerCommands.get(counter++));
+    Assert.assertEquals(
+        "  launch-command=bash,/test_container_work_dir/launch_container.sh",
+        dockerCommands.get(counter++));
+    Assert.assertEquals("  name=container_id", dockerCommands.get(counter++));
+    Assert
+        .assertEquals("  net=host", dockerCommands.get(counter++));
+    Assert.assertEquals("  ro-mounts=/test_filecache_dir:/test_filecache_dir,"
+            + "/test_user_filecache_dir:/test_user_filecache_dir",
+        dockerCommands.get(counter++));
+    Assert.assertEquals(
+        "  rw-mounts=/test_container_log_dir:/test_container_log_dir,"
+            + "/test_application_local_dir:/test_application_local_dir",
+        dockerCommands.get(counter++));
+    Assert.assertEquals("  user=" + uidGidPair, dockerCommands.get(counter++));
+    Assert.assertEquals("  workdir=/test_container_work_dir",
+        dockerCommands.get(counter));
+  }
+
   @Test
   @SuppressWarnings("unchecked")
   public void testContainerLaunchWithCustomNetworks()
@@ -686,7 +741,7 @@ public void testLaunchPidNamespaceContainersInvalidEnvVar()
     List<String> dockerCommands = Files.readAllLines(Paths.get
         (dockerCommandFile), Charset.forName("UTF-8"));
 
-    int expected = 15;
+    int expected = 14;
     Assert.assertEquals(expected, dockerCommands.size());
 
     String command = dockerCommands.get(0);
@@ -737,7 +792,7 @@ public void testLaunchPidNamespaceContainersEnabled()
     List<String> dockerCommands = Files.readAllLines(
         Paths.get(dockerCommandFile), Charset.forName("UTF-8"));
 
-    int expected = 16;
+    int expected = 15;
     int counter = 0;
     Assert.assertEquals(expected, dockerCommands.size());
     Assert.assertEquals("[docker-command-execution]",
@@ -749,7 +804,6 @@ public void testLaunchPidNamespaceContainersEnabled()
     Assert.assertEquals("  docker-command=run", dockerCommands.get(counter++));
     Assert.assertEquals("  group-add=" + String.join(",", groups),
         dockerCommands.get(counter++));
-    Assert.assertEquals("  hostname=ctr-id", dockerCommands.get(counter++));
     Assert
         .assertEquals("  image=busybox:latest", dockerCommands.get(counter++));
     Assert.assertEquals(
@@ -789,7 +843,7 @@ public void testLaunchPrivilegedContainersInvalidEnvVar()
     List<String> dockerCommands = Files.readAllLines(
         Paths.get(dockerCommandFile), Charset.forName("UTF-8"));
 
-    int expected = 15;
+    int expected = 14;
     Assert.assertEquals(expected, dockerCommands.size());
 
     String command = dockerCommands.get(0);
@@ -895,7 +949,7 @@ public void testLaunchPrivilegedContainersWithEnabledSettingAndDefaultACL()
     List<String> dockerCommands = Files.readAllLines(Paths.get
         (dockerCommandFile), Charset.forName("UTF-8"));
 
-    int expected = 16;
+    int expected = 15;
     int counter = 0;
     Assert.assertEquals(expected, dockerCommands.size());
     Assert.assertEquals("[docker-command-execution]",
@@ -907,7 +961,6 @@ public void testLaunchPrivilegedContainersWithEnabledSettingAndDefaultACL()
     Assert.assertEquals("  docker-command=run", dockerCommands.get(counter++));
     Assert.assertEquals("  group-add=" + String.join(",", groups),
         dockerCommands.get(counter++));
-    Assert.assertEquals("  hostname=ctr-id", dockerCommands.get(counter++));
     Assert
         .assertEquals("  image=busybox:latest", dockerCommands.get(counter++));
     Assert.assertEquals(
@@ -1012,7 +1065,7 @@ public void testMountSourceTarget()
     List<String> dockerCommands = Files.readAllLines(Paths.get
         (dockerCommandFile), Charset.forName("UTF-8"));
 
-    int expected = 15;
+    int expected = 14;
     int counter = 0;
     Assert.assertEquals(expected, dockerCommands.size());
     Assert.assertEquals("[docker-command-execution]",
@@ -1024,7 +1077,6 @@ public void testMountSourceTarget()
     Assert.assertEquals("  docker-command=run", dockerCommands.get(counter++));
     Assert.assertEquals("  group-add=" + String.join(",", groups),
         dockerCommands.get(counter++));
-    Assert.assertEquals("  hostname=ctr-id", dockerCommands.get(counter++));
     Assert.assertEquals("  image=busybox:latest",
         dockerCommands.get(counter++));
     Assert.assertEquals(
@@ -1085,7 +1137,7 @@ public void testMountMultiple()
     List<String> dockerCommands = Files.readAllLines(Paths.get
         (dockerCommandFile), Charset.forName("UTF-8"));
 
-    int expected = 15;
+    int expected = 14;
     int counter = 0;
     Assert.assertEquals(expected, dockerCommands.size());
     Assert.assertEquals("[docker-command-execution]",
@@ -1097,7 +1149,6 @@ public void testMountMultiple()
     Assert.assertEquals("  docker-command=run", dockerCommands.get(counter++));
     Assert.assertEquals("  group-add=" + String.join(",", groups),
         dockerCommands.get(counter++));
-    Assert.assertEquals("  hostname=ctr-id", dockerCommands.get(counter++));
     Assert.assertEquals("  image=busybox:latest",
         dockerCommands.get(counter++));
     Assert.assertEquals(
@@ -1140,7 +1191,7 @@ public void testUserMounts()
     List<String> dockerCommands = Files.readAllLines(
         Paths.get(dockerCommandFile), Charset.forName("UTF-8"));
 
-    int expected = 15;
+    int expected = 14;
     int counter = 0;
     Assert.assertEquals(expected, dockerCommands.size());
     Assert.assertEquals("[docker-command-execution]",
@@ -1152,7 +1203,6 @@ public void testUserMounts()
     Assert.assertEquals("  docker-command=run", dockerCommands.get(counter++));
     Assert.assertEquals("  group-add=" + String.join(",", groups),
         dockerCommands.get(counter++));
-    Assert.assertEquals("  hostname=ctr-id", dockerCommands.get(counter++));
     Assert.assertEquals("  image=busybox:latest",
         dockerCommands.get(counter++));
     Assert.assertEquals(
@@ -1635,7 +1685,7 @@ public void testDockerCommandPlugin() throws Exception {
     List<String> dockerCommands = Files.readAllLines(Paths.get
         (dockerCommandFile), Charset.forName("UTF-8"));
 
-    int expected = 16;
+    int expected = 15;
     int counter = 0;
     Assert.assertEquals(expected, dockerCommands.size());
     Assert.assertEquals("[docker-command-execution]",
@@ -1647,7 +1697,6 @@ public void testDockerCommandPlugin() throws Exception {
     Assert.assertEquals("  docker-command=run", dockerCommands.get(counter++));
     Assert.assertEquals("  group-add=" + String.join(",", groups),
         dockerCommands.get(counter++));
-    Assert.assertEquals("  hostname=ctr-id", dockerCommands.get(counter++));
     Assert
         .assertEquals("  image=busybox:latest", dockerCommands.get(counter++));
     Assert.assertEquals(
@@ -1775,7 +1824,7 @@ public void testLaunchContainerWithDockerTokens()
     List<String> dockerCommands = Files
         .readAllLines(Paths.get(dockerCommandFile), Charset.forName("UTF-8"));
 
-    int expected = 16;
+    int expected = 15;
     int counter = 0;
     Assert.assertEquals(expected, dockerCommands.size());
     Assert.assertEquals("[docker-command-execution]",
@@ -1789,7 +1838,6 @@ public void testLaunchContainerWithDockerTokens()
         dockerCommands.get(counter++));
     Assert.assertEquals("  group-add=" + String.join(",", groups),
         dockerCommands.get(counter++));
-    Assert.assertEquals("  hostname=ctr-id", dockerCommands.get(counter++));
     Assert.assertEquals("  image=busybox:latest",
         dockerCommands.get(counter++));
     Assert.assertEquals(