Service discovery failed for this host: Agent exited with code 255: Pseudo-terminal will not be allocated because stdin is not a terminal. Host key verification failed.

Current Setup: Ubuntu 14.04 running OMD

Solution: Running the ssh command from the OMD user appears to fix the problem by allowing them into the known hosts list.

Here’s how:

linuxuser@ubuntu_vm:~$ sudo su
[sudo] password for linuxuser:
root@ubuntu_vm:/home/scadmin# su [omd-site-name]
ubuntu_vm[[omd-site-name]]:~$

then run your remote command eg:

ubuntu_vm[[omd-site-name]]:~$ ssh -l root -i /etc/check_mk/check_mk.key [ip]

It will ask to save the host to the known hosts, type yes and enter. It should then output the status from the check_mk agent.