我的系统的centos4.1,今天看了yum服务，非常不错，马上测试一下。我的centos是用vmare装的，采用最小化安装。
我使用最小化安装，不过yum已经安装好了。我只需要编辑 CentOS-Base.repo 就可以。
把YUM的升级点改成这个镜像站：
#vi /etc/yum.repos.d/CentOS-Base.repo
把文件里的内容改成以下就可以了
[base]
name=CentOS-$releasever - Base
baseurl=http://mirror.be10.com/centos/$releasever/os/$basearch/
gpgcheck=1
#released updates
[update]
name=CentOS-$releasever - Updates
baseurl=http://mirror.be10.com/centos/$releasever/updates/$basearch/
gpgcheck=1
#packages used/produced in the build but not released
[addons]
name=CentOS-$releasever - Addons
baseurl=http://mirror.be10.com/centos/$releasever/addons/$basearch/
gpgcheck=1
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
baseurl=http://mirror.be10.com/centos/$releasever/extras/$basearch/
gpgcheck=1
###################################
这样你就可以用了，不过你只可以查询，不能安装。
[root@localhost yum.repos.d]# yum update kernel
You have enabled checking of packages via GPG keys. This is a good thing.
However, you do not have any GPG public keys installed. You need to download
the keys for packages you wish to install and install them.
You can do that by running the command:
rpm --import public.gpg.key
################################
你需要
运行
#####################
rpm --import http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-4
##################
这样就可以了，尝试升级内核
##################################
[root@localhost yum.repos.d]# yum update kernel
Setting up Update Process
Setting up Repos
addons 100% |=========================| 951 B 00:00
base 100% |=========================| 1.1 kB 00:00
update 100% |=========================| 951 B 00:00
extras 100% |=========================| 1.1 kB 00:00
Reading repository metadata in from local files
base : ################################################## 1499/1499
update : ################################################## 113/113
extras : ################################################## 114/114
Resolving Dependencies
--> Populating transaction set with selected packages. Please wait.
---> Downloading header for kernel to pack into transaction set.
kernel-2.6.9-42.0.3.EL.i6 100% |=========================| 206 kB 00:00
---> Package kernel.i686 0:2.6.9-42.0.3.EL set to be installed
--> Running transaction check
--> Processing Dependency: mkinitrd >= 4.2.1.6-1 for package: kernel
--> Restarting Dependency Resolution with new changes.
--> Populating transaction set with selected packages. Please wait.
---> Downloading header for mkinitrd to pack into transaction set.
mkinitrd-4.2.1.8-1.i386.r 100% |=========================| 31 kB 00:00
---> Package mkinitrd.i386 0:4.2.1.8-1 set to be updated
--> Running transaction check
Dependencies Resolved
Transaction Listing:
Install: kernel.i686 0:2.6.9-42.0.3.EL - update
Performing the following to resolve dependencies:
Update: mkinitrd.i386 0:4.2.1.8-1 - base
Total download size: 11 M
Is this ok [y/N]: y
Downloading Packages:
(1/2): mkinitrd-4.2.1.8-1 100% |=========================| 94 kB 00:00
(2/2): kernel-2.6.9-42.0. 100% |=========================| 11 MB 00:12
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
Updating: mkinitrd 100 % done 1/3
Installing: kernel 100 % done 2/3
Completing update for mkinitrd - 3/3
Installed: kernel.i686 0:2.6.9-42.0.3.EL
Dependency Updated: mkinitrd.i386 0:4.2.1.8-1
Complete!
###############################
