Questions[runlevel](ubuntu)

I need to kill some services when shutdown/reboot my Linux server, but I am not sure how Reboot command works.

To my understanding, /etc/rc0.d/ scripts will be invoked when system is shutdown, while the /etc/rc6.d/ scripts will be invoked when system is rebooted.

But according to this link: https://linux.die.net/man/8/reboot, reboot command also call shutdown command except when running on level 0 and 6, so does this mean /etc/rc0.d/ scripts are also invoked when reboot command is run ?

Do I only need to put the service kill script into /etc/rc0.d/ and /etc/rc1.d/ ? Or does it also need to be in /etc/rc6.d/ to make sure the service is stopped when reboot ?

Edit: Add my server configuration. Currently running Redhat, varying from 6.x to 7.2.

Today I was using my (old) Compaq laptop where Lubuntu is regularly installed on a partition. Suddenly, it stopped to respond to any inputs, so I (wrongly?) decided to restart the system.

After the logo Lubuntu had shown in the end of the booting process, the screen went black, the line

Stopping System V runlevel compatibility

showed and the two following messages

Asking for cache data failed 

and

Assuming drive cache: write through

repeatedly appeared. My laptop was stuck there and the operating system did not start.

I have been looking for some advice on the Internet during this afternoon, especially here on askubuntu.com, but it seems sadly that nobody has encountered exactly the same type of error. I am still working on that. If you have any ideas, please reply to this post.

Many Thanks

I want to find out in which runlevel the files of /etc/init.d‍ are started. Has someone any idea? I thought there might be the option to find it with the find command

If I want to shutdown my system in 30 minutes with telinit, how could I do it? I know that with shutdown is easier but just for knowing it.

i'm trying to change from runlevel 5 to runlevel 3 by running sudo init 3 command.
for some reason it doesn't do anything anymore.
the weird thing is that if i run the command runlevel it shows me that i'm at level 3.
tried to run init 5 and then init 3 and still nothing.

does anybody knows how to fix it?