keat63

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Nov 20, 2014
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I ran some updates this evening.
After rebooting the server, it failed to restart.

Luckily, my data centre quickly figured that it what he called a Kernel panic.
He restored the previous Kernel, and got the server back up.

Now I'm afraid to restart the yum update or reboot the server for fear of it happening again.
Any ideas on the way forward please. ?
 

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GOT

Get Proactive!
PartnerNOC
Apr 8, 2003
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I would look at the running kernel and remove any of the newer kernels.

You can prevent the kernel from updating by adding kernel* to the exclude line in /etc/yum.conf

You can wait for a newer kernel to come out and try that one or you could get a kernelcare subscription which will keep the kernel updated without actually needing to load a newer kernel.
 

cPanelLauren

Product Owner
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Ultimately your provider should be helping you determine why this occurred, you could hope and wait for a newer kernel version that may or may not have the same issue. If your provider can't assist you with this I'd suggest a system administrator if you don't have one you might find one here: System Administration Services | cPanel Forums

Thanks!
 

keat63

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Hi Lauren

I guess I am all those things.
I have a dedicated server, but it's not on a managed plan.
I manage this myself, and have done for the past 5 years without major incident.

The data centre tech support suggested removing the kernel and waiting for the next version, which I'm happy to do, but need a little help in doing so.
 

keat63

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Would the following command safely remove the kernel please.

yum remove kernel-2.6.32-754.14.2.e16.x86_64

and maybe remove reference to it from boot/grub/grub.conf

Code:
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,1)
#          kernel /vmlinuz-version ro root=/dev/mapper/VolGroup00-LogVol00
#          initrd /initrd-[generic-]version.img
#boot=/dev/sda
default=0
timeout=5
splashimage=(hd0,1)/grub/splash.xpm.gz
hiddenmenu
title CentOS (2.6.32-754.14.2.el6.x86_64)
   root (hd0,1)
   kernel /vmlinuz-2.6.32-754.14.2.el6.x86_64 ro root=/dev/mapper/VolGroup00-LogVol00 rd_NO_LUKS  KEYBOARDTYPE=pc KEYTABLE=uk LANG=en_GB.UTF-8 rd_MD_UUID=cdc443b0:8880de42:036bad34:1353413f SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=VolGroup00/LogVol00 rd_NO_DM rhgb quiet
title CentOS (2.6.32-754.10.1.el6.x86_64)
   root (hd0,1)
   kernel /vmlinuz-2.6.32-754.10.1.el6.x86_64 ro root=/dev/mapper/VolGroup00-LogVol00 rd_NO_LUKS  KEYBOARDTYPE=pc KEYTABLE=uk LANG=en_GB.UTF-8 rd_MD_UUID=cdc443b0:8880de42:036bad34:1353413f SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=VolGroup00/LogVol00 rd_NO_DM rhgb quiet
   initrd /initramfs-2.6.32-754.10.1.el6.x86_64.img
title CentOS (2.6.32-754.3.5.el6.x86_64)
   root (hd0,1)
   kernel /vmlinuz-2.6.32-754.3.5.el6.x86_64 ro root=/dev/mapper/VolGroup00-LogVol00 rd_NO_LUKS  KEYBOARDTYPE=pc KEYTABLE=uk LANG=en_GB.UTF-8 rd_MD_UUID=cdc443b0:8880de42:036bad34:1353413f SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=VolGroup00/LogVol00 rd_NO_DM rhgb quiet
   initrd /initramfs-2.6.32-754.3.5.el6.x86_64.img
title CentOS (2.6.32-754.2.1.el6.x86_64)
   root (hd0,1)
   kernel /vmlinuz-2.6.32-754.2.1.el6.x86_64 ro root=/dev/mapper/VolGroup00-LogVol00 rd_NO_LUKS  KEYBOARDTYPE=pc KEYTABLE=uk LANG=en_GB.UTF-8 rd_MD_UUID=cdc443b0:8880de42:036bad34:1353413f SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=VolGroup00/LogVol00 rd_NO_DM rhgb quiet
   initrd /initramfs-2.6.32-754.2.1.el6.x86_64.img
title CentOS (2.6.32-754.el6.x86_64)
   root (hd0,1)
   kernel /vmlinuz-2.6.32-754.el6.x86_64 ro root=/dev/mapper/VolGroup00-LogVol00 rd_NO_LUKS  KEYBOARDTYPE=pc KEYTABLE=uk LANG=en_GB.UTF-8 rd_MD_UUID=cdc443b0:8880de42:036bad34:1353413f SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=VolGroup00/LogVol00 rd_NO_DM rhgb quiet
   initrd /initramfs-2.6.32-754.el6.x86_64.img
 
Last edited:

keat63

Well-Known Member
Nov 20, 2014
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It looks like the command may have worked, but the warnings about file not existing makes me wonder if this was the cause of the panic ??

Code:
[email protected] [~]# yum remove kernel-2.6.32-754.14.2.el6.x86_64
Loaded plugins: fastestmirror, security, universal-hooks
Setting up Remove Process
Resolving Dependencies
--> Running transaction check
---> Package kernel.x86_64 0:2.6.32-754.14.2.el6 will be erased
--> Finished Dependency Resolution

Dependencies Resolved

======================================================================================================================
 Package                Arch                   Version                                Repository                 Size
======================================================================================================================
Removing:
 kernel                 x86_64                 2.6.32-754.14.2.el6                    installed                 133 M

Transaction Summary
======================================================================================================================
Remove        1 Package(s)

Installed size: 133 M
Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Erasing    : kernel-2.6.32-754.14.2.el6.x86_64                                                                  1/1
warning:    erase unlink of /lib/modules/2.6.32-754.14.2.el6.x86_64/modules.order failed: No such file or directory
warning:    erase unlink of /lib/modules/2.6.32-754.14.2.el6.x86_64/modules.networking failed: No such file or directory
warning:    erase unlink of /lib/modules/2.6.32-754.14.2.el6.x86_64/modules.modesetting failed: No such file or directory
warning:    erase unlink of /lib/modules/2.6.32-754.14.2.el6.x86_64/modules.drm failed: No such file or directory
warning:    erase unlink of /lib/modules/2.6.32-754.14.2.el6.x86_64/modules.block failed: No such file or directory
  Verifying  : kernel-2.6.32-754.14.2.el6.x86_64                                                                  1/1

Removed:
  kernel.x86_64 0:2.6.32-754.14.2.el6

Complete!
[email protected] [~]# rpm -q kernel
kernel-2.6.32-754.el6.x86_64
kernel-2.6.32-754.2.1.el6.x86_64
kernel-2.6.32-754.3.5.el6.x86_64
kernel-2.6.32-754.10.1.el6.x86_64
[email protected] [~]#
 

dalem

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Since your kernel never Loaded properly the modules never loaded.
Hence the error.

If you watch in the future when you upgrade a kernel & yum removes older kernels you will get the same error. You can safely ignore
 
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