Use shell script to change password for big cluster

I'm building a hadoop cluster with 50 nodes and I need to create a hadoop user and setup password on each node in the cluster.

If Ubuntu is running on the nodes of the cluster, I can do this in the shell script like this:

for i in `nodelist`; do
ssh $i /usr/sbin/groupadd hadoop
ssh $i /usr/sbin/useradd -g hadoop hadoop
ssh $i echo "hadoop" | passwd --stdin hadoop 

done

where nodelist is a text file and all the cluster nodes are listed there.

However, this does not work for Redhat Linux 6. You can not first do "ssh $i" to log on the remote machine and then do "echo 'hadoop' | passwd --stdin hadoop". What you can do is to create two script files. File A just covers adding user and changing password, script file B handles copying file A to each node on the cluster and run file A locally on each node.

For example, my file A looks like:

/usr/sbin/groupadd hadoop

 /usr/sbin/useradd -g hadoop hadoop

echo "hadoop" | passwd --stdin hadoop 

my file B looks like:

for i in `nodelist`; do

scp fileA $i:./

ssh $i ./fileA

done

Thus, I just need to create file A on the master node run fileB from there.