2 Server

First become root:

sudo su

Then run

apt-get update

and install the latest updates:

apt-get upgrade

Then install the package update-manager-core:

apt-get install update-manager-core

Open the file /etc/update-manager/release-upgrades...

vi /etc/update-manager/release-upgrades

... and make sure it has Prompt=normal in it:

[...]
Prompt=normal

Then run

do-release-upgrade

to start the distribution upgrade.

root@server1:~# do-release-upgrade
Checking for a new ubuntu release
Get:1 Upgrade tool signature [198 B]
Get:2 Upgrade tool [1550 kB]
Fetched 1550 kB in 0s (0 B/s)
authenticate 'precise.tar.gz' against 'precise.tar.gz.gpg'
extracting 'precise.tar.gz'

Reading cache

Checking package manager

Continue running under SSH?

This session appears to be running under ssh. It is not recommended
to perform a upgrade over ssh currently because in case of failure it
is harder to recover.

If you continue, an additional ssh daemon will be started at port
'1022'.
Do you want to continue?

Continue [yN] <-- y

Starting additional sshd

To make recovery in case of failure easier, an additional sshd will
be started on port '1022'. If anything goes wrong with the running
ssh you can still connect to the additional one.

To continue please press [ENTER] <-- ENTER

[...]

Do you want to start the upgrade?


2 installed packages are no longer supported by Canonical. You can
still get support from the community.

5 packages are going to be removed. 52 new packages are going to be
installed. 426 packages are going to be upgraded.

You have to download a total of 286 M. This download will take about
2 minutes with your connection.

Installing the upgrade can take several hours. Once the download has
finished, the process cannot be canceled.

 Continue [yN]  Details [d] <-- y

During the update, a few services might need a restart. If the update manager asks you which services should be restarted (it shows a list of services), just accept the default services by pressing ENTER.

At the end of the upgrade process, you should remove obsolete packages:

Remove obsolete packages?


19 packages are going to be removed.

 Continue [yN]  Details [d] <-- y

The server needs to be rebooted to complete the upgrade:

System upgrade is complete.

Restart required

To finish the upgrade, a restart is required.
If you select 'y' the system will be restarted.

Continue [yN] <-- y

After the reboot, your server is running Ubuntu 12.04. To be sure, take a look at /etc/issue:

cat /etc/issue

root@server1:~# cat /etc/issue
Ubuntu 12.04 LTS \n \l

root@server1:~#

3 Links

• Ubuntu: http://www.ubuntu.com/