sysadmin

We hosted Drupal websites at Hetzner for a few years. While it's unbeatable on price, it requires a skilled Linux sysadmin, which weights on personnel costs. Our guesstimate was that we'll pay a third more for a Drupal hosting, but our sysadmin costs would go down by ⅔. Add in non-material considerations, such as lower personnel turnover risks and better DDoS protection, and alternatives to Hetzner start to look almost attractive.

So, we decided to check Drupal cloud hosting solutions and asked for quotes from Pantheon and Acquia. Pantheon was less expensive and had more features. It also edged out Acquia on technology by using Linux containers instead of Amazon Web Services as underlying infrastructure. Unfortunately, Pantheon servers were located near Chicago, while most of our readers are from Europe, so we had no choice but to go for Acquia.

How it should work:

• insert a disk with a partition labelled as backup
• wait until the beep
• remove the disk

To label an ext3/ext4 disk, use

e2label device [newlabel]

Then, create an udev rule that runs your script when you insert a disk with a partition named backup:

echo 'KERNEL=="sd*", ENV{ID_FS_LABEL}=="backup", RUN+="/usr/local/bin/backup.sh"' 
   >> /etc/udev/rules.d/99-backup.rules

your backup script can be as simple as this:

#!/bin/sh
/bin/mount /dev/disk/by-label/backup /media/backup && \
  /usr/bin/rsync -r /home/* /media/backup && \
  /bin/umount /media/backup && \
  /usr/bin/beep

Watch out, $PATH is not set, you shoud use absolute paths everywhere.

To make it all work, reload udev rules with

udevadm control --reload-rules

Assuming that the internal screen is LVDS and the external screen is DVI-0. inotifywait comes from the inotify-tools package.

# Wait for the changes detected by the kernel laptop mode.
while inotifywait -e modify /proc/sys/vm/laptop_mode
do
laptop_mode=`cat /proc/sys/vm/laptop_mode`
  # If on battery, switch on the internal screen.
  if [[ $laptop_mode -gt 0 ]]; then
    xrandr --output LVDS --mode 1280x800
    xrandr --output DVI-0 --off
  # Otherwise,
  elif [[ $laptop_mode = 0 ]]; then
     # if the external screen is connected, switch it on.
     if [[ `xrandr -q|grep DVI-0|cut -f2 -d\ ` = connected ]]; then
       xrandr --output DVI-0 --mode 1920x1200
       xrandr --output LVDS --off
     fi
  fi
done

mknod backpipe p 
mknod log p
while :; do cat backpipe |nc -l -p 3001 |tee log| nc localhost 3000 |tee log >backpipe; done

Once in a time, I get to travel to places that make me worry about the data on my laptop. This time, it is not the US, but another openly democratic country where they kill you for a joint, let alone nude pictures. Enough politics, though.

I have a laptop with the /boot in a separate partition, followed by a /root partition and a /swap. Having a separate /boot is mandatory, as the BIOS has to load an unencrypted kernel and its initrd before being able to access the encrypted partition. Another option is to keep /boot on a USB stick, but its setup can take a whole other post.

First things first, let us install software for managing encrypted disks and updating the initrd image:

aptitude install cryptsetup initramfs-tools

We have to make sure that the encryption modules are present on the initrd, so I add the following three modules to the initrd config:

echo aes-i586 >>/etc/initramfs-tools/modules
echo dm-crypt >>/etc/initramfs-tools/modules
echo dm-mod >>/etc/initramfs-tools/modules

Next step is to inform cryptsetup and inittab of the partition mapping between /dev/hda2 (the physical device) and /dev/mapper/root (its encryption interface).

echo "root /dev/hda2 none luks" >>/etc/crypttab
sed -i 's#/dev/hda2#/dev/mapper/root#' /etc/fstab

We also have to change the root device for grub the same way we did it for inittab:

sed -i 's#/dev/hda2#/dev/mapper/root#' /boot/grub/menu.lst

Now, recreate the initrd image by issuing