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Gok Demir
Asked: 2011-10-03 23:51:41 +0800 CST

Upgrading CentOS does not update kernel version

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I am familiar with Debian based distros and now I have to administer CentOS machines. I have two CentOS 4.4 machine and I both applied 

yum upgrade

on them and they are both (lsb_release -a) 4.9 final now.

However when I looked the kernel version

uname -ar

One of them 

 Machine A: 2.6.9-42.0.3.ELsmp
 Machine B: 2.6.9-42.0.8.ELsmp

Then I copied Machine B's CentOS-Base.repo file to Machine A then copied B's yum.conf to A and I retried but yum upgrade but A's kernel version is still same. What can I do? What do I miss? Thanks

linux centos

2 Answers

  1. Best Answer

    you have to reboot for the kernel to actually update, at that point, uname will give the correct results.

    its worth pointing out that centos4 is now only on maintenance updates so you may want to consider also planning for a larger update to a later version of centos (currently 6.0 is latest)

    • 4

  2. The kernel is probably being excluded in your /etc/yum.conf file. You can check for excludes= lines in /etc/yum.conf

    # grep 'exclude' /etc/yum.conf

    You can either comment out the exclude= line or you can tell yum to disable the excludes for a single run with the command:

    # yum update --disableexcludes=all

    It's probably preferable to use the second form as you don't necessarily want the kernel and other packages updated without some supervision.

    HTH

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