In order to set a maintenance page in apache 2 you need:

  1. Enable mod_rewrite. In my debian server I just need to do the following:
    ln -s /etc/apache2/mods-available/rewrite.load /etc/apache2/mods-enabled/rewrite.load
  2. Create the maintenance page somewhere in your disk server. I created it under /srv/www/maintenance
  3. Set up apache2 to redirect all requests to your site to the maintenance page (you will need to comment out the current apache2 directives for your website). In my case I have a /etc/apache2/sites-available/mysite file that is linked from /etc/apache2/sites-enabled/mysite.
    #Maintenance page
    <VirtualHost *:80>
    ServerName mysite.com
    ServerAdmin postmaster@mysite.com
    RewriteEngine on
    RewriteCond %{REQUEST_URI} !/index\.html$
    RewriteCond %{REQUEST_URI} !/logo\.gif$
    RewriteRule ^(.*)$ /index.html [L]
    DocumentRoot “/srv/www/maintenance”
    </VirtualHost>
  4. Reload apache2 configuration:
    /etc/init.d/apache2 reload

In my case I only have an index.html and a logo.gif file in the /srv/www/maintenance folder. If you have more files that are needed to render the maintenance page you will need to add some extra “RewriteCond %{REQUEST_URI} !/yourfile\.extension$” rules.

Note if you do not use the rewrite engine, the maintenance page will show up when you users access http://mysite.com or http://mysite.com/index.html, but if they access http://mysite.com/something_else they will get a nice “Page not found error”.

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When one of the hard disks in a RAID 1 gets out of the RAID because it is no longer in sync with the other disk, you can easily resynchronize it with the following command:

raidhotadd /dev/mdX /dev/sdY

X and Y should be set to the appropriate values.

‘cat /proc/mdstat’ would tell you if your RAID system is healthy.

The configuration of your RAID is set in the file /etc/raidtab which will tell you the disks in the RAID and you can compare the results with the cat command above to see which disk is missing.

I use this script to verify if all disks in my RAID 1 are working fine:


#!/bin/bash
#Check if both drive are up
if [ `grep [UU] /proc/mdstat | wc -l` != 2 ] || [ `grep "2/2" /proc/mdstat | wc -l` != 2 ]; then
  cat /proc/mdstat
  exit 1
fi
exit 0

More info here.

Adding MS fonts to Ubuntu

February 26, 2007

Ubuntu does not install Microsoft fonts like Arial or Trebuchet by default, as I guess they are not free.

However you can get them from the multiverse packages. To install them, enable the multiverse packages in System/Administration/Sofware Sources and go to a terminal and type

sudo apt-get install msttcorefonts

Have you ever had the need to access an internal CVS repository from the office and from home or any other place outside your organization’s intranet? This is something I have been doing for quite a while now as I work from home from time to time.

We don’t use any kind of VPN as we don’t have the necessary hardware to set it up properly but I have access to an internal machine from home through ssh that then allows me to connect to the CVS machine.

The tip is to create a SSH tunnel to connect to the CVS machine (I use ssh to access CVS). That way, your CVS repository is always accessed through a port opened in your localhost and so it looks the same to applications regardless of how you connect to the CVS repository.

Imagine the following scenario:

My laptop hostname is laptop.domain, the CVS server is cvs.domain and the machine I use to connect to the intranet from home is gateway.domain.

When I am at home I create the following tunnel (replace username with your login name in gateway.domain):
ssh -L2222:cvs.domain:22 username@gateway.domain

When I am in the office I create the following tunnel:
ssh -L2222:cvs.domain:22 laptop.domain

Note that you MUST NOT replace laptop.domain with localhost in the second ssh tunnel. If you do that, the SSH key associated to localhost will be your laptop’s one and this will prevent you from making a ssh connection to cvs.domain through the tunnel because the SSH host key that will be reported will be the cvs.domain’s one that will conflict with the the SSH key already registered (you laptop’s one) and therefore the client will refuse to open the connection.

To make things easier I have created two aliases that I add to my .bashrc or .alias or .bash_aliases depending on your GNU/Linux distribution:

alias cvs_home=’ssh -L2222:cvs.domain:22 username@gateway.domain’
alias cvs_office=’ssh -L2222:cvs.domain:22 laptop.domain’

When you configure the repository in your CVS client specify:

  • host: localhost
  • port: 2222
  • connection protocol: ext:ssh or ssh

Ubuntu rocks!

February 22, 2007

Recently I installed Ubuntu on every machine in the office, servers and desktops and I must say that it just rocks.

It is very easy to install and configure. I have been using debian at home for quite a long time and adding new packages with apt-get is the simplest thing I have ever seen.

Actually I had an issue installing it on my laptop. The installation process just keep on hanging. But as always with GNU/Linux there are many alternatives available on the web so I decided to go for a network installation. It worked smoothly. Maybe you need some GNU/Linux administration backgound to do it, but it was my first network installation and it just worked.

One thing that sets Ubuntu appart from other GNU/Linux distributions is the huge documentation available. You can find detailed easy-to-follow steps to do about anything. For instance, do you want to add support for rich media cotent? Just follow the instructions here.

To sum up, if you plan on installing GNU/Linux (or even if you don’t 😉 ), give Ubuntu a go.