[hotfix] Include Hadoop version into EnvironmentInformation

docs/setup/yarn_setup.md

@@ -57,7 +57,7 @@ Apache [Hadoop YARN](http://hadoop.apache.org/) is a cluster resource management
 
 **Requirements**
 
-- Apache Hadoop 2.2
+- at least Apache Hadoop 2.2
 - HDFS (Hadoop Distributed File System) (or another distributed file system supported by Hadoop)
 
 If you have troubles using the Flink YARN client, have a look in the [FAQ section]({{ site.baseurl }}/faq.html).
@@ -79,7 +79,8 @@ tar xvzf flink-{{ site.version }}-bin-hadoop2.tgz
 cd flink-{{site.version }}/
 ~~~
 
-If you want to build the YARN .tgz file from sources, follow the [build instructions](building.html). You can find the result of the build in `flink-dist/target/flink-{{ site.version }}-bin/flink-{{ site.version }}/` (*Note: The version might be different for you* ).
+If you want to build the YARN .tgz file from sources, follow the [build instructions](building.html). 
+You can find the result of the build in `flink-dist/target/flink-{{ site.version }}-bin/flink-{{ site.version }}/` (*Note: The version might be different for you* ).
 
 
 #### Start a Session
@@ -208,9 +209,14 @@ Please note that the client then expects the `-yn` value to be set (number of Ta
 ./bin/flink run -m yarn-cluster -yn 2 ./examples/flink-java-examples-{{site.version }}-WordCount.jar 
 ~~~
 
-The command line options of the YARN session are also available with the `./bin/flink` tool. They are prefixed with a `y` or `yarn` (for the long argument options).
+The command line options of the YARN session are also available with the `./bin/flink` tool. 
+They are prefixed with a `y` or `yarn` (for the long argument options).
 
-Note: You can use a different configuration directory per job by setting the environment variable `FLINK_CONF_DIR`. To use this copy the `conf` directory from the Flink distribution and modify, for example, the logging settings on a per-job basis.
+Note: You can use a different configuration directory per job by setting the environment variable `FLINK_CONF_DIR`. 
+To use this copy the `conf` directory from the Flink distribution and modify, for example, the logging settings on a per-job basis.
+
+Note: It is possible to combine `-m yarn-cluster` with a detached YARN submission (`-yd`) to "fire and forget" a Flink job
+to the YARN cluster. In this case, your application will not get any accumulator results or exceptions from the ExecutionEnvironment.execute() call!
 
 
 ## Recovery behavior of Flink on YARN

flink-runtime/src/main/java/org/apache/flink/runtime/util/EnvironmentInformation.java

@@ -26,6 +26,7 @@
 import java.util.List;
 import java.util.Properties;
 
+import org.apache.hadoop.util.VersionInfo;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.apache.hadoop.security.UserGroupInformation;
@@ -280,6 +281,7 @@ public static void logEnvironmentInfo(Logger log, String componentName, String[]
 			log.info(" JVM: " + jvmVersion);
 			log.info(" Maximum heap size: " + maxHeapMegabytes + " MiBytes");
 			log.info(" JAVA_HOME: " + (javaHome == null ? "(not set)" : javaHome));
+			log.info(" Hadoop version: " + VersionInfo.getVersion());
 
 			if (options.length == 0) {
 				log.info(" JVM Options: (none)");