Heads up: starting hadoop

if you see this when you starting or stoping hadoop:


[hadoop@dev ~]$ start-dfs.sh 
13/10/25 22:21:07 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... 
using builtin-java classes where applicable Starting namenodes on [Java HotSpot(TM) 64-Bit Server VM warning: You have loaded library /home/hadoop/2.2.0/lib/native/libhadoop.so.1.0.0 which might have disabled stack guard. The VM will try to fix the stack guard now....... 
sed: -e expression #1, char 6: unknown option to `s' HotSpot(TM): ssh: 
Could not resolve hostname HotSpot(TM): Name or service not known 64-Bit: ssh: 
Could not resolve hostname 64-Bit: 
Name or service not known 

the workaround is to set the following environment variables: 
export HADOOP_HOME=/usr/local/hadoop 
export PATH=$HADOOP_HOME/bin:$PATH
export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_HOME/lib/native 
export HADOOP_OPTS="-Djava.library.path=$HADOOP_HOME/lib"