Thanks for replying. Actually Gave root permission to user running enable boot from script from ansible. Same ansible user as same level of permission on RHEL7 and RHEL 8. it is working on RHEL7&8. But only in few RHEL6 to some specific servers I see. this error "execve: No such file or directory\n while running command /sbin/chkconfig", "
Both disable and enable are not working to some RHEL6 servers.