SSH asks password when invoke it in script

Question

I have one master and four slave computers. I generated rsa public/private key on master PC. Then I copied publickey (id_rsa.pub) to slave machines as authorized_keys.

It doesn't ask password when I invoke SSH like this on master PC's terminal:

ssh –o UserKnownHostsFile=/dev/null –o StrictHostKeyChecking=no hduser@slave1 

I wrote this script to automatically login slave machines without asking password.

SERVER_LIST=`cat /home/hduser/slaves` # slave1, slave2 ...

for host in $SERVER_LIST; do
host=hduser@$host 
ssh –t –o UserKnownHostsFile=/dev/null –o StrictHostKeyChecking=no $host; 
done

SSH is asking slaves passwords when I use this script. I'm getting this message when use SSH with -vv option:

debug1: ssh_ecdsa_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /root/.ssh/id_rsa ((nil))
debug2: key: /root/.ssh/id_dsa ((nil))
debug2: key: /root/.ssh/id_ecdsa ((nil))
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Trying private key: /root/.ssh/id_rsa
debug1: Trying private key: /root/.ssh/id_dsa
debug1: Trying private key: /root/.ssh/id_ecdsa
debug2: we did not send a packet, disable method
debug1: Next authentication method: password
hduser@slave1's password:

I changed permissions on master PC and slave PC.

sudo chmod 755 /home/hduser    
sudo chmod 700 -R ~/.ssh
sudo chown hduser ~/.ssh

It doesn't ask password when I invoke SSH on terminal but It still asking password when invoke it in script. What am I missing? How can I fix it?

Answer 1

The SSH logs show that the login session is looking in /root/.ssh/ for the credentials, which implies your script is running as root.

Either copy your id_* files to /root/.ssh, generate the appropriate credentials as root, or run the script as the user where you have the credentials saved.