How do I remove old kernels?

[johnnyhop]

Fedora is my first dabble with a non-Debian distro, I'm still getting used to it and am pleased with the experience. My preference is to keep the current and immediately previous kernals installed and delete older kernels. Installed are 3.4.4-4, 3.4.6-1 and 3.4.7-1 and I'd like to remove 3.4.4-4. I'd appreciate any suggestions.

[sea]

At first you should be aware, that it is highly recommended to keep up to the last 3 kernel as Fedora has the most current ones, and with that, sometimes the most unstable ones...

Either way, to delete old and unwanted kernels, have a look into /boot.
Select those files that match the kernel version you want to delete. (THIS IS DANGEROUS, AND MIGHT CAUSE YOUR SYSTEM TO BE NOT BOOTABLE!)
And assuming its grub2, be sure to rebuild the grub config with : grub2-mkconfig -o /boot/grub2/grub.cfg

[nonamedotc]

Alternatively, use yum to remove the unwanted kernel(s). For example, in my case,

yum remove kernel-3.4.5-2.fc17

You can also configure how many kernels you want to retain by changing the corresponding value in /etc/yum.conf. The default is 3.

cat /etc/yum.conf 
[main]
cachedir=/var/cache/yum/$basearch/$releasever
keepcache=0
debuglevel=2
logfile=/var/log/yum.log
exactarch=1
obsoletes=1
gpgcheck=1
plugins=1
installonly_limit=3

[stoat]

Originally Posted by sea

Either way, to delete old and unwanted kernels, have a look into /boot.
Select those files that match the kernel version you want to delete.

You're right. That works. In fact, I have to delete kernels that way because I use a Linux from Scratch system in which everything in it was manually compiled. But just deleting the stuff in /boot leaves behind the kernel's modules folder, and sometimes its documentation. I have to delete those folders manually, too. So for a system like Fedora, the better idea probably is to delete unwanted kernels with its package manager to avoid leaving stuff behind.

[johnnyhop]

Thank you, I"ll use Yum, it sounds safest and most complete. I'll only do this afrter the current kernel proves stable.

[cryogenic666]

Originally Posted by johnnyhop

Thank you, I"ll use Yum, it sounds safest and most complete. I'll only do this afrter the current kernel proves stable.

The point here was that you don't NEED to manually remove the old kernels. If you leave the "installonly" variably at 3, it'll always keep three installed. When you go to install a new one, it'll delete the oldest one such that you have the latest + 2 older. Change it to two and you'll always have the latest + one older. But regardless, yum will auto-remove any kernels beyond the limit you set.