[FLINK-4998][yarn] fail if too many task slots are configured

This fails the deployment of the Yarn application if the number of task
slots are configured to be larger than the maximum virtual cores of the
Yarn cluster.

This closes apache#2741.

flink-yarn/src/main/java/org/apache/flink/yarn/AbstractYarnClusterDescriptor.java

@@ -23,6 +23,7 @@
 import org.apache.flink.configuration.ConfigConstants;
 import org.apache.flink.configuration.GlobalConfiguration;
 import org.apache.flink.configuration.HighAvailabilityOptions;
+import org.apache.flink.configuration.IllegalConfigurationException;
 import org.apache.flink.runtime.akka.AkkaUtils;
 import org.apache.flink.runtime.jobmanager.HighAvailabilityMode;
 import org.apache.flink.runtime.security.SecurityContext;
@@ -300,6 +301,14 @@ private void isReadyForDeployment() throws YarnDeploymentException {
 			throw new YarnDeploymentException("Flink configuration object has not been set");
 		}
 
+		int numYarnVcores = conf.getInt(YarnConfiguration.NM_VCORES, YarnConfiguration.DEFAULT_NM_VCORES);
+		// don't configure more than the maximum configured number of vcores
+		if (slots > numYarnVcores) {
+			throw new IllegalConfigurationException(
+				String.format("The number of task slots per node was configured with %d" +
+					" but Yarn only has %d virtual cores available.", slots, numYarnVcores));
+		}
+
 		// check if required Hadoop environment variables are set. If not, warn user
 		if(System.getenv("HADOOP_CONF_DIR") == null &&
 			System.getenv("YARN_CONF_DIR") == null) {

flink-yarn/src/test/java/org/apache/flink/yarn/YarnClusterDescriptorTest.java

@@ -0,0 +1,69 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.flink.yarn;
+
+import org.apache.flink.configuration.Configuration;
+import org.apache.flink.configuration.IllegalConfigurationException;
+import org.apache.hadoop.fs.Path;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+import java.io.File;
+import java.io.IOException;
+
+public class YarnClusterDescriptorTest {
+
+	@Rule
+	public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+	private File flinkJar;
+	private File flinkConf;
+
+	@Before
+	public void beforeTest() throws IOException {
+		temporaryFolder.create();
+		flinkJar = temporaryFolder.newFile("flink.jar");
+		flinkConf = temporaryFolder.newFile("flink-conf.yaml");
+	}
+
+	@Test
+	public void testFailIfTaskSlotsHigherThanMaxVcores() {
+
+
+		YarnClusterDescriptor clusterDescriptor = new YarnClusterDescriptor();
+
+		clusterDescriptor.setLocalJarPath(new Path(flinkJar.getPath()));
+		clusterDescriptor.setFlinkConfiguration(new Configuration());
+		clusterDescriptor.setConfigurationDirectory(temporaryFolder.getRoot().getAbsolutePath());
+		clusterDescriptor.setConfigurationFilePath(new Path(flinkConf.getPath()));
+
+		// configure slots too high
+		clusterDescriptor.setTaskManagerSlots(Integer.MAX_VALUE);
+
+		try {
+			clusterDescriptor.deploy();
+		} catch (Exception e) {
+			Assert.assertTrue(e.getCause() instanceof IllegalConfigurationException);
+		}
+	}
+
+
+}