ssh: Could not resolve hostname guard.: Name or service not known

错误状况

guard.: ssh: Could not resolve hostname guard.: Name or service not known
now.: ssh: Could not resolve hostname now.: No address associated with hostname
-c: Unknown cipher type 'cd'
noexecstack'.: ssh: Could not resolve hostname noexecstack'.: Name or service not known
hadoop01: starting namenode, logging to /opt/module/hadoop-2.5.0/logs/hadoop-root-namenode-hadoop01.out
hadoop01: Java HotSpot(TM) Client VM warning: You have loaded library /opt/module/hadoop-2.5.0/lib/native/libhadoop.so.1.0.0 which might have disabled stack guard. The VM will try to fix the stack guard now.
hadoop01: It's highly recommended that you fix the library with 'execstack -c <libfile>', or link it with '-z noexecstack'.
loaded: ssh: Could not resolve hostname loaded: Temporary failure in name resolution
warning:: ssh: Could not resolve hostname warning:: Temporary failure in name resolution

解决方法：添加hadoop如下部分到环境变量中

HADOOP_HOME=/opt/module/hadoop-2.5.0
export PATH=$PATH:$HADOOP_HOME/bin:$HADOOP_HOOME/sbin:$HADOOP_HOME/lib
export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_HOME/lib/native
export HADOOP_OPTS="-Djava.library.path=$HADOOP_HOME/lib"