YARN-8916. Define a constant docker string in ContainerRuntimeConstants.java for better maintainability. (Zhankun Tang via wangda)

Change-Id: I1349e740037f81afdbe30edbe741f20e88fd0a90

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

@@ -266,7 +266,8 @@ public class DockerLinuxContainerRuntime implements LinuxContainerRuntime {
     if (type == null) {
       type = daemonConf.get(YarnConfiguration.LINUX_CONTAINER_RUNTIME_TYPE);
     }
-    return type != null && type.equals("docker");
+    return type != null && type.equals(
+        ContainerRuntimeConstants.CONTAINER_RUNTIME_DOCKER);
   }
 
   /**

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

@@ -30,4 +30,8 @@ public class ContainerRuntimeConstants {
   @Private
   public static final String ENV_CONTAINER_TYPE =
       "YARN_CONTAINER_RUNTIME_TYPE";
+
+  @Private
+  public static final String CONTAINER_RUNTIME_DOCKER =
+      "docker";
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/container/TestContainer.java

@@ -1587,7 +1587,8 @@ public class TestContainer {
 
     public void setupDockerContainerEnv() {
       Map<String, String> env = new HashMap<>();
-      env.put(ContainerRuntimeConstants.ENV_CONTAINER_TYPE, "docker");
+      env.put(ContainerRuntimeConstants.ENV_CONTAINER_TYPE,
+          ContainerRuntimeConstants.CONTAINER_RUNTIME_DOCKER);
       when(this.ctxt.getEnvironment()).thenReturn(env);
     }
 

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/linux/resources/gpu/TestGpuResourceHandler.java

@@ -124,7 +124,8 @@ public class TestGpuResourceHandler {
     ContainerLaunchContext clc = mock(ContainerLaunchContext.class);
     Map<String, String> env = new HashMap<>();
     if (dockerContainerEnabled) {
-      env.put(ContainerRuntimeConstants.ENV_CONTAINER_TYPE, "docker");
+      env.put(ContainerRuntimeConstants.ENV_CONTAINER_TYPE,
+          ContainerRuntimeConstants.CONTAINER_RUNTIME_DOCKER);
     }
     when(clc.getEnvironment()).thenReturn(env);
     when(c.getLaunchContext()).thenReturn(clc);

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

@@ -63,7 +63,7 @@ public class TestDelegatingLinuxContainerRuntime {
   @Test
   public void testIsRuntimeAllowedDocker() throws Exception {
     conf.set(YarnConfiguration.LINUX_CONTAINER_RUNTIME_ALLOWED_RUNTIMES,
-        "docker");
+        ContainerRuntimeConstants.CONTAINER_RUNTIME_DOCKER);
     delegatingLinuxContainerRuntime.initialize(conf, null);
     assertTrue(delegatingLinuxContainerRuntime.isRuntimeAllowed(
         LinuxContainerRuntimeConstants.RuntimeType.DOCKER.name()));
@@ -153,7 +153,8 @@ public class TestDelegatingLinuxContainerRuntime {
   @Test
   public void testJavaSandboxNotAllowedButPermissiveDockerRequested()
       throws Exception {
-    env.put(ContainerRuntimeConstants.ENV_CONTAINER_TYPE, "docker");
+    env.put(ContainerRuntimeConstants.ENV_CONTAINER_TYPE,
+        ContainerRuntimeConstants.CONTAINER_RUNTIME_DOCKER);
     conf.set(YarnConfiguration.LINUX_CONTAINER_RUNTIME_ALLOWED_RUNTIMES,
         "default,docker");
     conf.set(YarnConfiguration.YARN_CONTAINER_SANDBOX, "permissive");

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

@@ -334,7 +334,8 @@ public class TestDockerContainerRuntime {
     Map<String, String> envDockerType = new HashMap<>();
     Map<String, String> envOtherType = new HashMap<>();
 
-    envDockerType.put(ContainerRuntimeConstants.ENV_CONTAINER_TYPE, "docker");
+    envDockerType.put(ContainerRuntimeConstants.ENV_CONTAINER_TYPE,
+        ContainerRuntimeConstants.CONTAINER_RUNTIME_DOCKER);
     envOtherType.put(ContainerRuntimeConstants.ENV_CONTAINER_TYPE, "other");
 
     Assert.assertEquals(false, DockerLinuxContainerRuntime
@@ -350,8 +351,10 @@ public class TestDockerContainerRuntime {
     Map<String, String> envDockerType = new HashMap<>();
     Map<String, String> envOtherType = new HashMap<>();
 
-    conf.set(YarnConfiguration.LINUX_CONTAINER_RUNTIME_TYPE, "docker");
-    envDockerType.put(ContainerRuntimeConstants.ENV_CONTAINER_TYPE, "docker");
+    conf.set(YarnConfiguration.LINUX_CONTAINER_RUNTIME_TYPE,
+        ContainerRuntimeConstants.CONTAINER_RUNTIME_DOCKER);
+    envDockerType.put(ContainerRuntimeConstants.ENV_CONTAINER_TYPE,
+        ContainerRuntimeConstants.CONTAINER_RUNTIME_DOCKER);
     envOtherType.put(ContainerRuntimeConstants.ENV_CONTAINER_TYPE, "other");
 
     Assert.assertEquals(true, DockerLinuxContainerRuntime
@@ -368,7 +371,8 @@ public class TestDockerContainerRuntime {
     Map<String, String> envOtherType = new HashMap<>();
 
     conf.set(YarnConfiguration.LINUX_CONTAINER_RUNTIME_TYPE, "default");
-    envDockerType.put(ContainerRuntimeConstants.ENV_CONTAINER_TYPE, "docker");
+    envDockerType.put(ContainerRuntimeConstants.ENV_CONTAINER_TYPE,
+        ContainerRuntimeConstants.CONTAINER_RUNTIME_DOCKER);
     envOtherType.put(ContainerRuntimeConstants.ENV_CONTAINER_TYPE, "other");
 
     Assert.assertEquals(false, DockerLinuxContainerRuntime