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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

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up vote 4 down vote accepted

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)

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I see B has installonlypkgs=kernel kernel-smp kernel-devel kernel-smp-devel kernel-largesmp kernel-largesmp-devel kernel-hugemem kernel-hugemem-devel But A does not have in yum.conf (although I copied it B to A after upgrade process) so it needs reboot. Thanks – Gok Demir Oct 3 '11 at 8:24
But A does not have in yum.conf so it needs reboot – Gok Demir Oct 3 '11 at 8:24

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.


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