The standard XenServer 5.6 does not have a template for the latest CentOS 5.5 distribution. But this is not a big problem: simply install CentOS 5.3 first, then upgrade to the latest CentOS 5.5 release.

  1. Install CentOS 5.3 using the CentOS-5.3-i386-bin-DVD.iso image
  2. Run yum update. This will start the (lengthy) update process to CentOS 5.5. After installation, the version can be verified using rpm -qa | grep centos-release.
  3. Install the XenServer tools.
  4. At this point CentOS 5.5 is properly installed. The following notes are some additional configuration changes and serve as a documentation to one of my personal systems.
  5. Install the RPMForge Repo (see also http://wiki.centos.org/AdditionalResources/Repositories/RPMForge:) 
    #wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.1-1.el5.rf.i386.rpm
wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.1-1.el5.rf.x86_64.rpm
rpm --import http://apt.sw.be/RPM-GPG-KEY.dag.txt
rpm -K rpmforge-release-0.5.1-1.el5.rf.*.rpm
rpm -i rpmforge-release-0.5.1-1.el5.rf.*.rpm
yum check-update
  6. Install the ATrpms Repo. Create a new file /etc/yum.repos.d/ATrpms.repo with the following content: 
    [atrpms-stable]
name=Centos $releasever - $basearch - ATrpms
baseurl=http://dl.atrpms.net/el$releasever-$basearch/atrpms/stable
gpgkey=http://ATrpms.net/RPM-GPG-KEY.atrpms
gpgcheck=1
enabled=1
includepkgs=libspf2* libsrs*

[atrpms-testing]
name=Centos $releasever - $basearch - ATrpms
baseurl=http://dl.atrpms.net/el$releasever-$basearch/atrpms/testing
gpgkey=http://ATrpms.net/RPM-GPG-KEY.atrpms
gpgcheck=1
enabled=1
includepkgs=exim*
    Then run yum update. This will allow us to install exim-4.72 (which has DKIM) instead of the standard exim-4.63.
    #install the Apache httpd, PHP and Pear-DB 
    yum install apache php php-pear-DB
  7. Now install exim: 
    yum install exim
....
================================================================================================================================================================
 Package                                 Arch                           Version                                    Repository                              Size
================================================================================================================================================================
Installing:
 exim                                    x86_64                         4.72-41.el5                                atrpms-testing                         1.3 M
Installing for dependencies:
 libspf2_2                               x86_64                         1.2.5-5.0.el5                              atrpms-stable                           49 k
 libsrs_alt1                             x86_64                         1.0-3_rc1.0.el5                            atrpms-stable                           12 k
 mysql                                   x86_64                         5.0.77-4.el5_5.3                           updates                                4.8 M
 postgresql-libs                         x86_64                         8.1.21-1.el5_5.1                           updates                                196 k

Transaction Summary
================================================================================================================================================================
Install       5 Package(s)
Upgrade       0 Package(s)

Total download size: 6.3 M
Is this ok [y/N]: y
Downloading Packages:
(1/5): libsrs_alt1-1.0-3_rc1.0.el5.x86_64.rpm                                                                                            |  12 kB     00:00
(2/5): libspf2_2-1.2.5-5.0.el5.x86_64.rpm                                                                                                |  49 kB     00:00
(3/5): postgresql-libs-8.1.21-1.el5_5.1.x86_64.rpm                                                                                       | 196 kB     00:00
(4/5): exim-4.72-41.el5.x86_64.rpm                                                                                                       | 1.3 MB     00:00
(5/5): mysql-5.0.77-4.el5_5.3.x86_64.rpm                                                                                                 | 4.8 MB     00:00
----------------------------------------------------------------------------------------------------------------------------------------------------------------