upgrade.sh

#!/bin/bash
set -euxo pipefail

# Wait for cloud-init to finish
if [ "$(cloud-init status | perl -ne '/^status: (.+)/ && print $1')" != "disabled" ]; then
  cloud-init status --long --wait
fi

# Let the sudo group members use root permissions without a password.
# NB d-i automatically added the vagrant user into the sudo group.
sed -i -E "s,^%sudo\s+.+,%sudo ALL=(ALL) NOPASSWD:ALL,g" /etc/sudoers

# Configure apt for non-interactive mode
export DEBIAN_FRONTEND=noninteractive

# Disable unattended upgrades.
# NB it interferes with our automation with errors like:
#     E: Could not get lock /var/lib/dpkg/lock-frontend. It is held by process 17599 (unattended-upgr)
#     E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it?
sudo apt-get -qq remove --purge unattended-upgrades

# Upgrade
sudo apt-get -qq update && sudo apt-get -qq dist-upgrade