At time of writing, on a standard Kimsufi, OVH provide you with one static IP, and three “failover IP’s” these “failover” IP’s are just normal IP’s, although they don’t have their own gateway (since only the host machine is allowed to use the gateway). The only thing that’s different about these “failover” IP’s is that if you have more than one Kimsufi or dedicated server with OVH then you can simply change which server the failover IP is routed to, which is quite handy for DR (disaster recovery) or even load balancing.

Let’s get started, first, you need to set up your server with the default CentOS image that is provided by OVH (this may already be the case if you requested this image when you ordered), if not, this is done by selecting your server from the dropdown box at the top of the manager screen, then clicking on “Services” beneath the “Dedicated servers” menu on the left-hand side. While in this menu,  ensure that “Netboot” is set to “hd” so that the boot process is kicked to the hard disk and not OVH’s custom kernels. Next, choose “Reinstall / Change OS” and follow the steps here to install CentOS, the partitioning doesn’t really matter, where possible just choose the default options and continue through the steps until the installation process starts.

The installation process will continue and wipe your server clean and replace it with OVH’s CentOS image (which I might add, isn’t a TRUE CentOS kernel, as provided by the CentOS project). Once you’ve received your email from OVH confirming that the reinstall is complete and have got your new root password, log into the server via SSH. When you have a prompt, type the following commands:

mkdir /cleaninstall
cd /cleaninstall

For 32-bit CentOS:

wget http://ftp.hosteurope.de/mirror/centos.org/5/os/i386/images/pxeboot/initrd.img
wget http://ftp.hosteurope.de/mirror/centos.org/5/os/i386/images/pxeboot/vmlinuz

For 64-bit CentOS:

wget http://ftp.hosteurope.de/mirror/centos.org/5/os/x86_64/images/pxeboot/initrd.img
wget http://ftp.hosteurope.de/mirror/centos.org/5/os/x86_64/images/pxeboot/vmlinuz

Then copy the pxe boot files to the /boot partition

cp vmlinuz /boot/vmlinuz.cent.pxe
cp initrd.img /boot/initrd.img.cent.pxe

Next we need to set up the GRUB bootloader:

yum install grub

Empty the bootloader sequence and insert our new config:

cat /dev/null > /boot/grub/menu.lst
vi /boot/grub/menu.lst

Paste the below text in this file amending the following variables to suit your info:
YOURPASSWORD = A password of your choosing, this is a a temporary password and is only used during the installation via VNC
IPADDR = The IP address of your OVH server (host)
GATEWAY = The gateway IP address of your OVH server (find this by doing: # netstat -r | grep default)

For 32-bit CentOS:

default 0
timeout 30
title Centos Install (PXE)
        root (hd0,0)
        kernel /boot/vmlinuz.cent.pxe vnc vncpassword=YOURPASSWORD headless ip=IPADDR netmask=255.255.255.0 gateway=GATEWAY dns=213.186.33.99 ksdevice=eth0 method=http://ftp.hosteurope.de/mirror/centos.org/5/os/i386/ lang=en_US keymap=us
        initrd /boot/initrd.img.cent.pxe

For 64-bit CentOS:

default 0
timeout 30
title Centos Install (PXE)
        root (hd0,0)
        kernel /boot/vmlinuz.cent.pxe vnc vncpassword=YOURPASSWORD headless ip=IPADDR netmask=255.255.255.0 gateway=GATEWAY dns=213.186.33.99 ksdevice=eth0 method=http://ftp.hosteurope.de/mirror/centos.org/5/os/x86_64/ lang=en_US keymap=us
        initrd /boot/initrd.img.cent.pxe

Save the file (in this sequence hit Escape, colon (:), x, Enter)

Next we need to install GRUB into the MBR of the server disk so…

grub-install /dev/sda
grub-install --recheck /dev/sda

Once that’s done, we need to bounce the box:

shutdown -r now

Wait a couple of minutes for the server to come back online (you can monitor it using ping requests). Once the server is contactable again fire up a VNC client and in the connection box type in the IP address of your server followed by “:1″, for example, if your IP was 192.168.0.5, the VNC connection box will read 192.168.0.5:1

Enter the password you specified as and you will be presented a VNC window at the first step of the CentOS installation screen. Follow the installer (make sure you leave the network options alone – for now at least). After the installation completes and reboots, you now have a PROPER CentOS installation free from OVH’s meddling hands.

Install VMWare Server 2 as you would normally on CentOS, there are tons of HOWTO’s out there on that subject I’m sure. One thing I will say about installing VMWare Server 2 is that when asked about configuring a bridged network interface, to be honest, I wouldn’t configure one, you’ll only need NAT and Host-Only networking. To configure a Bridged interface just invites a headache of having your switch-port blocked if you ever switch on a guest VM which tries to make use of it – which can be very frustrating and WILL cause an interruption to service while OVH sort out unblocking your MAC address from their network.

So, once we’ve got VMware Server 2 installed and running, we need to set up the networking so that the “failover IPs” can be used for the virtual guests. We’re going to be doing this using routed IP’s as it’s the simplest way, without having to involve NAT’ing (ugly).

We’ll start off by configuring the host machine to allow proxied arp requests on the VMware host-only interface, which in this case is the “vmnet1″ device – this is the default interface name that VMware Server creates, however if yours is different you’ll need to amend the below steps accordingly (this is only if you’ve had a non-standard VMware install).

echo "net.ipv4.conf.vmnet1.proxy_arp=1" >> /etc/sysctl.conf && sysctl -p

Next on the host, we have to create a static route to allow traffic to flow to the “failover IP’s”

IPFAILOVER is to be subsituted with one of your failover IP’s. e.g 10.0.0.11

ip route add IPFAILOVER dev vmnet1

A line like the one above is required for each failover IP which you’ll be routing.

This would not survive a reboot (bad) so we have to do something a little more inventive…
We need to create a network config file in the /etc/sysconfig/network-scripts folder to set up the interface dynamically, since VMware doesn’t actually configure the interface using the standard method. In short, we need a config file to set up the interface so that CentOS is “aware” of it, and then we also need to create a route file for the interface too to set up the routing for the interface at boot.

So…
First off we need to find out what interface subnet the vmware installer picked to use for the vmnet1 interface on the host server, so do a

ifconfig vmnet1 | grep "inet addr"

From the output of the above command, use the “inet addr:” address for the IPADDR= and use the “Mask:” for the NETMASK=

Create and populate the /etc/sysconfig/network-scripts/ifcfg-vmnet1 file with the below info:

vi /etc/sysconfig/network-scripts/ifcfg-vmnet1

DEVICE=vmnet1
IPADDR=*.*.*.*
NETMASK=*.*.*.*
ONBOOT=yes

Now that CentOS is aware of that network interface, the routing config to the VM’s fail-over IP needs to go into /etc/sysconfig/network-scripts/route-vmnet1 which is done by:

vi /etc/sysconfig/network-scripts/route-vmnet1

IPFAILOVER dev vmnet1

A new line like the one above is required for each failover IP which you’ll be routing.

Now, unfortunately, that doesn’t solve all our problems because VMware server starts up after the networking service and thus after the virtual device is created. So we need a way to restart the networking service after VMware has started. The quickest and dirtiest way of doing that is by putting something in /etc/rc.local which will do the job. I hated having to do this, purely because it’s not “kosher” with the distro, and in general bad practise, but needs must…

echo "/sbin/service network restart &> /tmp/network-restart" >> /etc/rc.local

Ok, so now we need to allow traffic through to the virtual machines. This is done using the iptables kernel module on the host machine (or can be done on the guest so long as there’s a rule on the host allowing all traffic through to that failover IP). Generally speaking, I like to keep my firewall rules in one place for ease of management, and that’s on the host. So, we’ll open up the iptables config file (or use my script to make it easier):

vim /etc/sysconfig/iptables

Find the line:

-A RH-Firewall-1-INPUT -m state --state NEW -m udp -p udp --dport 1194 -j ACCEPT

and insert this line below it subsituting where necessary (below example is allowing port 22 (ssh) access through to this failover IP):

-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 22 -d FAILOVERIP -j ACCEPT

As above, a new line (rule) like the one above is required for each failover IP which you’ll be routing.

As far as the server, or rather, host side is concerned, we’re finished. Now we just need to configure the guest OS with the failover IP address (or addresses if you so choose). The virtual machine should be configured to use the following:

Linux hosts:
IP= FAILOVERIP
NETMASK=255.255.255.255
GATEWAY= FAILOVERIP (yes it’s the same as the interface IP)

Windows hosts:
IP= FAILOVERIP
NETMASK=255.255.255.248
GATEWAY= FAILOVERIP (yes it’s the same as the interface IP)

The DNS nameservers can be set anything you wish to use, so long as they’re addressable and accessible by the VM’s. I tend to use OpenDNS‘s servers unless I’m using my own.

#!/bin/bash
TESTING_MINS=2
vim /etc/sysconfig/iptables
clear
QUESTION1="Do you want to restart the firewall now? (hit 't' to test for $TESTING_MINS min(s)) [y/n/t] "
echo -n $QUESTION1

a=""
while test -z "$a"
do
        read -n1 a
        echo ""

 case "$a" in
  Y|y)
        echo -e "Restarting...\n\n"
		/sbin/service iptables restart
  ;;
  N|n)
        exit 0
  ;;
  T|t)
        echo -e "Time is now `date +%H:%M` -firewall service will be stopped at `date +%H:%M -d "+$TESTING_MINS min"`\nIf your test was successful, you will need to manually start the service again by running:\nservice iptables start"
        echo "/sbin/service iptables stop &> /dev/null" | at now + $TESTING_MINS min &> /dev/null
		echo ""
        /sbin/service iptables restart
  ;;
  *)
        a=""
        echo -n $QUESTION1
  ;;
  esac
done

P.S. Any scripts I write and publish here are © Rob Freeman and released under the GPL unless otherwise stated.

yum clean all
mkdir /usr/src/centos
cd /usr/src/centos
wget http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
wget http://mirror.centos.org/centos/5/os/i386/CentOS/centos-release-5-3.el5.centos.1.i386.rpm
wget http://mirror.centos.org/centos/5/os/i386/CentOS/centos-release-notes-5.3-3.i386.rpm
wget http://mirror.centos.org/centos/5/os/i386/CentOS/yum-3.2.19-18.el5.centos.noarch.rpm
wget http://mirror.centos.org/centos/5/os/i386/CentOS/yum-updatesd-0.9-2.el5.noarch.rpm
wget http://mirror.centos.org/centos/5/os/i386/CentOS/yum-fastestmirror-1.1.16-13.el5.centos.noarch.rpm
rpm –-import RPM-GPG-KEY-CentOS-5
/bin/rpm -e --nodeps redhat-release
/bin/rpm -e --nodeps rhn-client-tools
/bin/rpm -e --nodeps yum-rhn-plugin
rpm -Uvh --force *.rpm
yum upgrade

How painless was that?!

I’ve just noticed that Redmine version 0.8.5 was released last week, while this HOWTO should still be valid, I have not yet tested it so please report any issues you experience with new installs in the comments and I’ll look into them and amend the HOWTO where necessary

[Updated 3rd June 2009]

So since Assembla changed it’s strategy and forced a monetised service or your once private projects were to become public after some date in February I decided to set up my own subversion repos / web management interface.

I never really used the Assembla service to its full potential however and all I really needed was a basic SVN setup with a webinterface to show the diffs in an eye-friendly format. The only two real choices were Trac and Redmine. I’d already used Trac on Assembla and countless other project sites so I was more drawn to Redmine due to it’s good interface design (imo, the Trac interface looks like it’s stuck together with Lego pieces), its features are more integrated and well, I fancied a change. The only problem was that Redmine runs on Ruby on Rails which I’ve heard very bad things about. So I decided to take a plunge and find out wtf the hassle was all about. It turns out there weren’t any up-to-date, well written and well maintained HOWTO’s out there detailing how to get a functional RoR environment configured on CentOS / RHEL. So I wrote my own (after hitting several brick walls)…

HOWTO: Install Subversion, Ruby on Rails and Redmine on CentOS5 (& RHEL5)

NOTES

• This HOWTO is written for CentOS 5.2 [updates for 5.3 in purple text]
• Replace [FQDN] with either your IP address or the hostname (or FQDN) which you’ll be using to access the interface.
• Replace [user] with the username under whom’s home directory the Subversion repository database will be located. e.g. /home/[user]/svn-repos

• This HOWTO will be using the following variables:

• You already have the “httpd” (apache) package installed
• You will be running apache as the user ‘apache’
• The subversion repository root folder will be under /home/[user]/subversion/
• The vhost’s folder locationg will be /var/www/svn
• The subversion repository to be created will be called ‘example-repo’

Install and set up Subversion

yum install mod_dav_svn subversion

Add the group [user] to the user apache and make the subversion base URL readable and writable…

usermod -aG [user] apache
chmod g+x /home/[user]
mkdir /home/[user]/subversion
chmod g+rwx /home/[user]/subversion
chown -R [user]:[user] /home/[user]/subversion

Make the web directory:

mkdir /var/www/svn
chown apache.apache /var/www/svn

Put the following into /etc/httpd/conf.d/svn.conf (this is for a sub-repo called ‘example-repo’)

NameVirtualHost *:80
<VirtualHost *:80>
        DocumentRoot "/var/www/svn"
        ServerName [FQDN]
        <Location /example-repo>
                DAV svn
                SVNPath /home/[user]/subversion/example-repo
                AuthType Basic
                AuthName "Subversion repo"
                AuthUserFile /var/www/passwd
                Require valid-user
        </Location>

        <Directory "/var/www/svn">
        allow from all
        Options +Indexes
        </Directory>
</VirtualHost>

Add an HTTP auth user…

htpasswd -cm /var/www/passwd [user]

Create a proper SVN repository

cd /home/[user]/subversion
su [user] -c "svnadmin create example-repo"

Import any SVN repos by doing:

su [user] -c "svnadmin load example-repo < /path/to/repo/dump/file"

Make sure the permissions are correct

chmod g+rwx /home/[user]/subversion
chown -R [user].[user] /home/[user]

Install Ruby on Rails

*NOTE: Ruby on Rails installation requires the EPEL yum repository (at time of writing).

su -c 'rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-3.noarch.rpm'

Let’s get Ruby up and running first… [NOTE: not on an SElinux environment cba with that]

yum install httpd httpd-devel apr make gcc-c++ mysql-server mysql ruby ruby-devel ruby-docs ruby-ri \
ruby-libs ruby-mode ruby-tcltk ruby-irb ruby-rdoc fcgi fcgi-devel mod_fcgid rubygems subversion-ruby

Now we’ll install passenger (aka mod_rails)

gem install passenger
passenger-install-apache2-module

Create and insert this text into /etc/httpd/conf.d/rails.conf (or alternatively edit the existing svn.conf created when we set up subversion)
NOTE:

• The below configuration is specific to the installation of redmine (hence the DocumentRoot)

LoadModule passenger_module /usr/lib/ruby/gems/1.8/gems/passenger-2.0.6/ext/apache2/mod_passenger.so
   PassengerRoot /usr/lib/ruby/gems/1.8/gems/passenger-2.0.6
   PassengerRuby /usr/bin/ruby

NameVirtualHost *:80

   <VirtualHost *:80>
     ServerName 192.168.10.17
     DocumentRoot /var/www/rails/redmine/public
   </VirtualHost>

Now on to Redmine itself

Get Redmine 0.8 from http://www.redmine.org/wiki/redmine/Download

cd /usr/src
svn co http://redmine.rubyforge.org/svn/branches/0.8-stable redmine-0.8
mkdir /var/www/rails/
cd /var/www/rails/
cp -r /usr/src/redmine-0.8/ redmine/
chown -R apache.apache redmine
cd redmine

Create a clean backup of source files

tar czf Redmine0.8-clean.tar.gz .

Initialise mySQL:

service mysqld start

To secure mysql:

mysql_secure_installation

Create a mysql database for redmine…

mysql -u[username] -p

At the prompt enter:

create database redmine character set utf8;

Quit with:

quit

Copy the example database file to the “live” location

cd /var/www/rails/redmine
cp config/database.yml.example config/database.yml

Enter the appropriate settings for the [production] section ensuring that host is set to 127.0.0.1

vim /var/www/rails/redmine/config/database.yml

Set up email

cd /var/www/rails/redmine
cp config/email.yml.example config/email.yml

Enter the appropriate settings for the [production] section ensuring that “address” is set to the IP address of the SMTP host

vim /var/www/rails/redmine/config/email.yml

Install rails for redmine using gem…

cd /var/www/rails/redmine/app/
gem install -v=2.1.2 rails

Import the redmine database into the live database specified in the above config file

cd /var/www/rails/redmine/app/
rake db:migrate RAILS_ENV="production"

Install default configuration data in database (this is entirely optional, but recommended).

cd /var/www/rails/redmine/app/
rake redmine:load_default_data RAILS_ENV="production"

Bring up the testing webserver, once loaded check your config by browsing to http://[FQDN]:3000

cd /var/www/rails/redmine/
ruby script/server -e production

Make sure your apache config file edits are ok and that the services will start at boot by doing:

service httpd configtest
service httpd restart
chkconfig httpd on
chkconfig mysqld on

[Optional:] Add the following to your crontab which will create a database backup in the /home/[user] directory

/usr/bin/mysqldump -u <user> -p <password> <database> | gzip > /home/[user]/redmine_`date +%y_%m_%d`.gz

Make your subversion server configuration accessible to redmine by doing the following:

mkdir /etc/subversion
cp -r /root/.subversion/* /etc/subversion/
vim /var/www/rails/redmine/lib/redmine/scm/adapters/subversion_adapter.rb

Change the line:

SVN_BIN = "svn"

to:

SVN_BIN = "svn --config-dir /etc/subversion"

Then restart apache:

service httpd restart

On the other hand however we have the Mercedes road car which has drawn all of the experience of building the engines and parts for the F1 car, but have had the time to mature the technology used in F1, make it extremely resilient and safe and put it all into a stable car. You can be confident driving the road car that nothing will break unexpectedly and that even if it does, you can take it to the garage and they’ll figure out what’s wrong and make it right again (bug fixes). You get air bags (RHCE’s ). You also get the peace of mind knowing that the car has a warranty and will last for a long time to come, and that parts will always be available for it, and that the tyres won’t wear down quickly etc. All because you know the car has been safety tested and engineered to withstand a crash and a break-down.

I think that’s about as far as I can take the analogy – but I’m sure you get the drift

Rather than run the installation on my live server(s), I decided to do a test install on a Virtual Machine. I fired up VMWare and created a minimal installation of CentOS (and I mean minimal) and after installing VMware tools I installed the GNOME desktop along with the X11 Window Manager. I normally use KDE, but unfortunately Dropbox only currently supports Nautilus and not Konqueror .

yum --exclude=nautilus-sendto groupinstall 'X Window System' 'GNOME Desktop Environment'

Now, officially CentOS is not supported by Dropbox, there are no packages for CentOS provided by Dropbox so I thought I’d get the source and see what I could do with it. The package requirements are higher than the CentOS package versions available through traditional channels. I thought I’d have a pop anyway and document how far I got here. The two key problems are that Dropbox require glib2 version to be at least 2.14.0 and libnotify needs to be at least 0.4.4. CentOS 5.2 (current release at time of writing) only has packages for glib2 at 2.12.3-2 and libnotify at 0.4.2-6. I wasn’t about to let that stop my potential enjoyment of Dropbox though, so I installed the other dependencies using yum:

yum install bzip2 wget make gtk+-devel libnotify-devel nautilus-extensions.i386 nautilus-devel.i386 gnome-vfs2-devel compat-glibc-headers.i386 compat-glibc.i386 gnome-desktop-devel.i386

Then I got the latest source from the DropBox download page and untarred it:

wget http://dl.getdropbox.com/u/5143/nautilus-dropbox-packages/0.4.1/nautilus-dropbox-0.4.1.tar.bz2
tar jxf nautilus-dropbox-0.4.1.tar.bz2

Next, I had to alter the configure script to accept our versions of glib2 and libnotify which was just a matter of finding and replacing

GLIB_REQUIRED=2.14.0
LIBNOTIFY_REQUIRED=0.4.4

with

GLIB_REQUIRED=2.12.0
LIBNOTIFY_REQUIRED=0.4.2

Then I ran the

./configure
make
make install

Everything seemed to compile ok. Time to fire up the desktop… GNOME launched ok, but nautilus refuses to load. The problem is revealed when trying to start nautilus from the command line:

[rob@localhost ~]$ nautilus /home/rob
Initializing nautilus-dropbox 0.4.1
nautilus: symbol lookup error: /usr/lib/nautilus/extensions-1.0/libnautilus-dropbox.so: undefined symbol: g_timeout_add_seconds

It looks like Dropbox really does require the specified versions of those packages which is a real shame. So in short, unless anyone comes up with a workaround, or Dropbox release a more compatible version it looks like there’s no awesomeness to be had with Dropbox and CentOS / RHEL

Never-the-less the awesomeness still reigns on the Windows platform!