Hadoop Java HotSpot execstack warning

Hadoop binaries are built for 32 bit runtime.   If you run the hadoop binaries on a 64 bit machine, you might notice this warning on running any hadoop command.

For help on how to install Hadoop Cluster, checkout my article on hadoop.

[Java HotSpot(TM) 64-Bit Server VM warning: You have loaded library /home/hadoopuser/hadoop/lib/native/libhadoop.so.1.0.0 which might have disabled stack guard. The VM will try to fix the stack guard now.
It’s highly recommended that you fix the library with ‘execstack -c <libfile>’, or link it with ‘-z noexecstack’.
0.0.0.0]

The warning could further manifest into following messages:

[Java HotSpot(TM) 64-Bit Server VM warning: You have loaded library /home/hadoopuser/hadoop/lib/native/libhadoop.so.1.0.0 which might have disabled stack guard. The VM will try to fix the stack guard now.
It's highly recommended that you fix the library with 'execstack -c ', or link it with '-z noexecstack'.
0.0.0.0]
sed: -e expression #1, char 6: unknown option to `s'
64-Bit: ssh: Could not resolve hostname 64-bit: Name or service not known
warning:: ssh: Could not resolve hostname warning:: Name or service not known
HotSpot(TM): ssh: Could not resolve hostname hotspot(tm): Name or service not known
VM: ssh: Could not resolve hostname vm: Name or service not known
You: ssh: Could not resolve hostname you: Name or service not known
Java: ssh: Could not resolve hostname java: Name or service not known
have: ssh: Could not resolve hostname have: Name or service not known
Server: ssh: Could not resolve hostname server: Name or service not known
loaded: ssh: Could not resolve hostname loaded: Name or service not known
which: ssh: Could not resolve hostname which: Name or service not known
library: ssh: Could not resolve hostname library: Name or service not known
might: ssh: Could not resolve hostname might: Name or service not known
disabled: ssh: Could not resolve hostname disabled: Name or service not known
have: ssh: Could not resolve hostname have: Name or service not known
stack: ssh: Could not resolve hostname stack: Name or service not known
guard.: ssh: Could not resolve hostname guard.: Name or service not known
will: ssh: Could not resolve hostname will: Name or service not known
The: ssh: Could not resolve hostname the: Name or service not known
VM: ssh: Could not resolve hostname vm: Name or service not known
try: ssh: Could not resolve hostname try: Name or service not known
to: ssh: Could not resolve hostname to: Name or service not known
-c: Unknown cipher type 'cd'
fix: ssh: Could not resolve hostname fix: Name or service not known
stack: ssh: Could not resolve hostname stack: Name or service not known
guard: ssh: Could not resolve hostname guard: Name or service not known
the: ssh: Could not resolve hostname the: Name or service not known
now.: ssh: Could not resolve hostname now.: Name or service not known
It's: ssh: Could not resolve hostname it's: Name or service not known
recommended: ssh: Could not resolve hostname recommended: Name or service not known
highly: ssh: Could not resolve hostname highly: Name or service not known
that: ssh: Could not resolve hostname that: Name or service not known
you: ssh: Could not resolve hostname you: Name or service not known
the: ssh: Could not resolve hostname the: Name or service not known
fix: ssh: Could not resolve hostname fix: Name or service not known
with: ssh: Could not resolve hostname with: Name or service not known
library: ssh: Could not resolve hostname library: Name or service not known
'execstack: ssh: Could not resolve hostname 'execstack: Name or service not known
',: ssh: Could not resolve hostname ',: Name or service not known
or: ssh: Could not resolve hostname or: Name or service not known
it: ssh: Could not resolve hostname it: Name or service not known
link: ssh: Could not resolve hostname link: Name or service not known
with: ssh: Could not resolve hostname with: Name or service not known
'-z: ssh: Could not resolve hostname '-z: Name or service not known
noexecstack'.: ssh: Could not resolve hostname noexecstack'.: Name or service not known

To fix this annoying warning, update your hadoop-env.sh file under etc/hadoop, and replace following line

# Extra Java runtime options.  Empty by default.
export HADOOP_OPTS="$HADOOP_OPTS -Djava.net.preferIPv4Stack=true"

with the following line, by adding  -XX:-PrintWarnings

# Extra Java runtime options.  Empty by default.
export HADOOP_OPTS="$HADOOP_OPTS -XX:-PrintWarnings -Djava.net.preferIPv4Stack=true"

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