# Ubuntu Server 18.04 LTS upgrade issues and their solutions

I run KVM, PostgreSQL, Kubernetes and the ELK Stack on Ubuntu at home. These computers were running Ubuntu Server 16.04 LTS. These are the solutions to the problems encountered during the upgrade to the latest LTS version 18.04.

Disclaimer: These solutions may not be appropriate for you. Follow them at your own risk.

Upgrade Process

The operating system prompts you to upgrade whenever you log into a computer with an outdated distribution.
After creating the mandatory backups I ran the suggested command.

do-release-upgrade

The upgrade is relatively smooth. It displays several prompts, and everything works fine until it doesn’t.

Problems during the upgrade

/boot partition is full

Some computers that run for years, accumulate old kernels in the /boot partition. The upgrade reaches a point where apt crashes and nothing can be installed.

This guide to cleanup the /boot partition proved invaluable.

Note: The process to remove old kernels may have to be executed multiple times. Because sudo apt-get -f install can fill the /boot partition again.

Problems after the upgrade

Local DNS configuration disappeared

Every upgraded computer lost their local DNS configuration.

cat /etc/resolv.conf should print something like this:

nameserver 192.168.1.1   # your local DNS IP
search router123456.com  # your local search domain

If that is not the case, load the DNS configuration from the new location

sudo mv /etc/resolv.conf /etc/resolv.conf.bck
sudo ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf

KVM virtual machines failed to start

Sample Error:

$ virsh start vm1
error: Failed to start domain vm1
error: the CPU is incompatible with host CPU: Host CPU does not provide required features: hle, rtm

Note: These were virtual machines that were running on that same computer before the upgrade.

This Red Hat bug report has instructions to correct the issue.

Step 1: Edit the vm:

virsh edit vm1

Step 2: Add the following features to the cpu xml node

<feature policy='disable' name='rtm'/>
<feature policy='disable' name='hle'/>

Laptop screen does not turn off after long inactivity

This used to work in the old 16.04 version.

For the new 18.04 version I took a different approach. These commands make sure the computer doesn’t suspend when the lid is closed.

sudo sed -i 's/#HandleLidSwitchDocked=ignore/HandleLidSwitchDocked=ignore/g' /etc/systemd/logind.conf
sudo sed -i 's/#HandleLidSwitch=suspend/HandleLidSwitch=ignore/g' /etc/systemd/logind.conf
sudo reboot

Deprecated PostgreSQL package

The upgrade process mentioned the installed PostgreSQL version was deprecated. And that I should try running pg_upgradecluster and reading /usr/share/doc/postgresql-common/README.Debian.gz.

Since I had a backup of my data I reinstalled PostgreSQL and everything kept working just fine.

Bottomline

Although the Ubuntu 18.04 upgrade was not free of hiccups, these proved to be relatively easy to solve. Moreover, there was enough troubleshooting documentation readily available.