First of all my Linux knowledge is limited! I'm more a developer, who casually manages some servers :-)
So, I'm operating on a farm of RHEL5/6 (mixed) servers and here is what I want to do: I have a Java program on one master server, which runs commands on some remote machines. The Java program sends my commands to the OS correctly - local commands can be executed without problems. My problem is the execution of commands on the remote servers:
- I've got the SSH keys, which allows my master to simply obtain root privileges on the slaves
- My command works, if I trigger it directly via a terminal (e.g.
ssh firstname.lastname@example.org "cd /opt/bla")
- I've tried different approaches, with different results - none of them correct :)
$ ssh email@example.com Pseudo-terminal will not be allocated because stdin is not a terminal. Host key verification failed.
So, being familiar with Google, I've read about tty which was supposed to solve the problem but only lead to:
$ ssh -t -t firstname.lastname@example.org tcgetattr: Invalid argument The authenticity of host '192.168.1.1 (192.168.1.1)' can't be established. RSA key fingerprint is <somehex>.
So my application got stuck at this point, weirdly after Ctrl+C'ing it I've seen the following text:
Are you sure you want to continue connecting (yes/no)? Killed by signal 2.
So I'm assuming that something was working, it just got stuck on the input.
However, I was unable to find anything conclusive about this error. One hint somewhere was to edit
/etc/sudoers and comment out (I know it's not recommend)
# Defaults requiretty
which didn't do anything, although I have no idea if I should change this setting on the master and/or the slave and if a reboot or some restart of a daemon is required.
My question now is: does this lead anywhere or are my attempts worthless? Or is there any better way to run remote commands on slaves triggered by a program on the master machine? Please keep in mind I won't recompile my kernel or do any complicated shenanigan, since I'm simply lacking the experience with Linux..
Help is highly appreciated!