If you have a Fedora live disk you can boot to that and use the chroot method to install grub from your Fedora install on your disk.  A bit more complicated but good tutorials out there.

Things are always complicated when you do several distros on a single disk.  A bit easier if separate disks.  You might consider investing in a USB-SSD caddy case and SSD so you can boot external if you only use the function occasionally.  Or if you have a DVD drive bay there are SSD drive by converters for that - loose the DVD drive but have a second "hard disk".  I did this on my newest laptop to avoid trying to install W8 and Linux on the same drive.  It worked out fine.


On Mon, Jul 11, 2016 at 10:38 AM, Tod Merley <todbot88@gmail.com> wrote:
Ok, I meant to say "Google is our friend".  I consider myself your friend but the time to put together tutorials on procedures where many already exist is not what I plan to do today.

On Mon, Jul 11, 2016 at 10:36 AM, Tod Merley <todbot88@gmail.com> wrote:
It sounds like your "most recent" distro is Fedora - so - re-install grub from Fedora.  Google is your friend.

On Mon, Jul 11, 2016 at 6:45 AM, Kevin Wilson <wkevils@gmail.com> wrote:
Hi,
Thanks Todd.
The thing is that now CentOS is installed and it is the current
control and it indeed uses an older grub. So what do you suggest ?
That I will reinstall Ubuntu on Fedora on the current machine so they
will the "current control"? It is quite a hassle as there is no free
partition for it (unless I will resize it); and already there are 3 OS
installed on that machine. I believe there should be another way to do
it with the old grub without installing another OK on the same
machine,

Regards,
Kevin

On Sun, Jul 10, 2016 at 9:40 PM, Tod Merley <todbot88@gmail.com> wrote:
> I mean run "update-grub" from the Ubuntu distribution.  It is the control.
>
> On Sun, Jul 10, 2016 at 11:38 AM, Tod Merley <todbot88@gmail.com> wrote:
>>
>> On a multi-boot machine the big question is “who controls the boot
>> process”.
>>
>>
>> My “big box” has two SSD (Ubuntu, CentOS) a 1T HDD (eight Linux partitions
>> if memory serves) and a small clunky HDD with W7.
>>
>>
>> In this case I choose Ubuntu to control the boot process and understand
>> that if I update the Kernel in any of the other distros I will not be able
>> to boot to it unless I run update-grub (Ubuntu script similar to your
>> mkconfig command) which will look at all the partitions and disks to boot to
>> the most recent first.
>>
>>
>> Likely CentOS is your current control and it likely uses an older grub.
>>
>>
>> Choose a recent “grub2” distro and make it your “boot control”.
>
>
>