Use the sample JCL HOSTSAVE (shown below) from <HLQ>.V650.SAMPLIB to accept host keys without user interaction. Edit the JCL to suit your needs. You can consult the Tectia Server for IBM z/OS User Manual for an explanation of all the available options for the ssh-keydist-g3 command.

HOSTSAVE:

//HOSTSAV EXEC PGM=BPXBATSL,REGION=0M,TIME=NOLIMIT
//STDPARM  DD  *
PGM /opt/tectia/bin/ssh-keydist-g3
  -v  -N  -F plain  -i  -A /tmp/newhosts.log 
  host1 host2 host3 
//STDENV   DD  DSN=<HLQ>.V650.PARMLIB(SSHENV),DISP=SHR 
//STDOUT   DD  SYSOUT=*
//STDERR   DD  SYSOUT=*
//STDIN    DD  DUMMY
//*

	Enable verbose mode.
	Accept new host keys automatically.
	Store the accepted host keys in plain file name format.
	Store the accepted host keys also using the IP addresses of the hosts.
	The accepted host keys will be listed in the log file specified here.
	Your host names or IP addresses go here.
	Required environment variables are set here (see Environment Variables).