#!/bin/sh -eux
export DEBIAN_FRONTEND=noninteractive

echo "disable release-upgrades"
sed -i.bak 's/^Prompt=.*$/Prompt=never/' /etc/update-manager/release-upgrades;

echo "disable systemd apt timers/services"
systemctl stop apt-daily.timer;
systemctl stop apt-daily-upgrade.timer;
systemctl disable apt-daily.timer;
systemctl disable apt-daily-upgrade.timer;
systemctl mask apt-daily.service;
systemctl mask apt-daily-upgrade.service;
systemctl daemon-reload;

# Disable periodic activities of apt to be safe
cat <<EOF >/etc/apt/apt.conf.d/10periodic;
APT::Periodic::Enable "0";
APT::Periodic::Update-Package-Lists "0";
APT::Periodic::Download-Upgradeable-Packages "0";
APT::Periodic::AutocleanInterval "0";
APT::Periodic::Unattended-Upgrade "0";
EOF

echo "remove the unattended-upgrades and ubuntu-release-upgrader-core packages"
rm -rf /var/log/unattended-upgrades;
apt-get -y purge unattended-upgrades ubuntu-release-upgrader-core;

echo "update the package list"
apt-get -y update;

echo "upgrade all installed packages incl. kernel and kernel headers"
apt-get -y dist-upgrade -o Dpkg::Options::="--force-confnew";

reboot