Upgrading Ubuntu 12.04 LTS to 14.04 LTS

Not much to go on here.

So I was just upgrading a production server to 14.04 LTS from 12.04, and I thought I might as well post something in case anyone searched for how to do it.

First, check your release version with this command:

$ lsb_release -a

It should give an output similar to:

Linux 3.2.0-51-generic x86_64
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 12.04.4 LTS
Release:	12.04
Codename:	precise

Now that you are sure of your version, grab all the necessary updates from the apt sources.

$ sudo apt-get update

If you don't have update-manager installed, (it should be installed by default, even on the server distros) you can do the following.

$ sudo apt-get install update-manager-core

Next step is to perform the upgrade.

$ sudo do-release-upgrade

On many instances, including mine, you will receive this message.

Checking for a new Ubuntu release
No new release found

This is because the update-manager is set not to upgrade between LTS versions. So we need to force the issue. The following command has the -d option which stands for -devel-release. It will upgrade to the latest development, or unstable, version. Which at the time of this writing, happens to be 14.04. You can check which version it will download before it starts.

$ sudo do-release-upgrade -d

This will start a prompt that upgrades the system to the latest development release.

Follow the terminal prompts, and you should be done!