First, there isn’t a Fedora 20 release yet, but you can download a nightly build of it. Fedora 20 is branched out from Rawhide Release, and that means people who run Rawhide -possibly- have slightly different packages from F20, that are version-ed as Fedora 21.
Fedora 20 DHCP and SELINUX Bugs
Yesterday I booted my Fedora 20 box and I end up without Internet Connection. The bug was in DCHP package, but manually set up was also broken, so I couldn’t update my system and fix the issue. After I updated Fedora through a Live CD, I end up to a new bug that I couldn’t login to the system.
That was caused by a bug to SELINUX, and you need to disable it.
I usually avoid LVM Partitions as they cause troubles with Grub -specially in my case with lots of SSDs and OSs . When I firstly installed Fedora 20, Anaconda was buggy and it was impossible to set up custom partitions, so I end up with defaults, an LVM.
Well, I discovered tha LVM isn’t only tricky to configured it on Grub, but is also kinda hard to mount it :)
Mount a LVM Partition
The procedure to restore a broken installation, is to use live CD/DVD/USB, mount the Fedora Partition, Chroot to it, and trying to fix the issues as you were logged in to a normal installation. Note, that Fedora 20 Live CD hasn’t a repair option, so you have mount partition manually.
1. Boot in Live CD
First boot Fedora in Live Mode with a CD, open a Terminal and switch to Root with “su” -password is not required.
2. Read physical Drives
Pvs tool will print information about physical volumes.
PV VG Fmt Attr PSize PFree /dev/sda5 fedora lvm2 a-- 19.58g 0
This is the only available partition so it will be probably be the one we need.
3. Get info of a logical drive
lvdisplay tool will give us a information about our logical drive. In this case “fedora”, but you have to adjust accordingly to your details.
# lvdisplay fedora
--- Logical volume --- LV Path /dev/fedora/swap LV Name swap VG Name fedora LV UUID cFhs0Y-ZJ3K-jlKe-ac87-zOqF-ZASS-iGY876 LV Write Access read/write LV Creation host, time localhost, 2013-09-17 17:35:08 +0300 LV Status available # open 2 LV Size 7.77 GiB Current LE 1988 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:0 --- Logical volume --- LV Path /dev/fedora/root LV Name root VG Name fedora LV UUID GZj8jq-CRgK-np6P-Nwdl-NMTZ-AY3e-pBu3E1 LV Write Access read/write LV Creation host, time localhost, 2013-09-17 17:35:08 +0300 LV Status available # open 1 LV Size 11.82 GiB Current LE 3025 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:1
Check on LV Name and LV size and you will figure out what is the filesystem partition you need. In this case is the “/dev/fedora/root”.
4. Create a mount point
Traditionally mounted partitions were under /mnt. So lets create a folder under it and later on we will mount our filesystem there. I will call it “fedora”.
# mkdir /mnt/fedora
5. Scan Volume Groups
vgscan tool scan all disks for volume groups and rebuild caches. We run this with “–mknodes” option that also checks the LVM special files in /dev that are needed for active logical volumes and creates any missing ones and removes unused ones.
# vgscan --mknodes
Reading all physical volumes. This may take a while... Found volume group "fedora" using metadata type lvm2
6. Change Attrs of a Logical Drive
Now we will use the lvchange tool to change the attributes of our logical drive making them known to the kernel ready for use. We will use the “-ay” option in order to activate the logical volume.
#lvchange -a y /dev/fedora/root
7. Mount the LVM
Then we are ready to mount our LVM partition with the broken Fedora installation
# mount /dev/fedora/root /mnt/fedora
If you “cd” inside “/mnt/fedora”, you will able to see your filesystem and retrieve files. Do that to make sure you have the one you need!
8. Change Root
Just chroot in your mounted point.
# chroot /mnt/fedora
From here you can update your system with yum command or fix any other issues you might have.
# yum update
Restart and you will have all the updates! That fixed my DCHP issue but not the SELINUX.
SELINUX bug in Fedora 20 pre-alpha
When I reboot -after I had updated my system with the above method- I had this weird bug that was preventing me to login on my system. Every time I was entering my credentials it was keeping log me out! I didn’t Google for the bug, as I assumed was a SELINUX issue. And I was right ;)
I again mount my filesystem (Zzz..), and I disabled SELINUX
# vi /etc/selinux/config
# This file controls the state of SELinux on the system. # SELINUX= can take one of these three values: # enforcing - SELinux security policy is enforced. # permissive - SELinux prints warnings instead of enforcing. # disabled - No SELinux policy is loaded. SELINUX=disabled # SELINUXTYPE= can take one of these two values: # targeted - Targeted processes are protected, # minimum - Modification of targeted policy. Only selected processes are protected. # mls - Multi Level Security protection. SELINUXTYPE=targeted
If you run a Rawhide or F20 pre-alpha this is the solution for the login bug.
The instruction for mounting LVM partions is from: