I have been practicing redhat Linux in my virtual machine quite a lot and I am quite confident.
I felt really really bad to fail the exam twice.
It seems my node2 work was never saved in the previous exam and in this exam.
Actually I have booted the node 2 twice and I definitely saw the storage related configuration was there. But I lost all the scores for this area. Last time, I got the reply that " one of your system did not reboot to a usable state and could not be graded"
I do not know what happened. It must be a very small, but extremely critical point I have missed. This never happen in my local virtual machine environment.
Can anybody help and give your hint?
I completely sympathize. I wouldn't think a student would be expected (or allowed) to authenticate to external repos. Neither would I expect an exam taker to be given a login to an external registry, or allowed to use a RHN or other account to do it. I can say for certain that if repos are housed inside the exam environment, the method I outlined above should do it with 'yum repolist all.' Ricardo says in the RH124 v8 course to make sure the file extension is .repo. I've made the same error during exercises occasionally, forgetting the .repo extension altogether. Though that is quickly remedied.
I know this is frustrating. When I recertified for RHEL 7 I had to retake the exam several times even though I had passed for RHEL 4 & 6 on the first attempts with them. The exams are really tough but there is a reason for that. Once one has passed these very tough tests, the reputation of toughness enhances our value in the job market.
On your concern about registration, RHEL does not need to be registered via subscription manager to use local repos. You will probably get a warning that the system should be registered but this does not stop the system from using local repos.
While I can't state exactly how, that would be prohibited, I can tell you that I was able to login and complete the exam successfully. It is not easy, it is possible.