Upgrade Ubuntu 10.04 server to 12.04 LTS

According to Ubuntu 12.04 release notes, "It is generally recommended that users of Ubuntu 10.04 LTS wait until the first point release, due in July, before upgrading."

If you do want to wait until the 12.04.1 is released in July 2012, follow the following steps:

1. Ensure you're up to date with latest updates for Ubuntu 10.04:

   sudo apt-get update
   sudo apt-get upgrade
   

2. Install update-manager-core if it is not already installed:

   sudo apt-get install update-manager-core
   

3. Edit /etc/update-manager/release-upgrades and set Prompt=lts:

   [DEFAULT]
   Prompt=lts
   

4. Launch the upgrade tool, and follow the on-screen instructions:

   sudo do-release-upgrade -d
   

NOTE:

At the end of the upgrade process you will be required to restart the server in order to boot into the new kernel. If you do not have access to the console of the system you are upgrading, you may need to edit /boot/grub/menu.lst and change the default boot kernel to the newly installed 12.04 kernel. If this step is not performed your server may attempt to boot into the 10.04 LTS kernel and will hang.