setup.sh

#!/bin/sh

# Enable openssh server
rc-update add sshd default

# Configure networking
cat > /etc/network/interfaces <<-EOF
iface lo inet loopback
iface eth0 inet dhcp
EOF

ln -s networking /etc/init.d/net.lo
ln -s networking /etc/init.d/net.eth0

rc-update add net.eth0 default
rc-update add net.lo boot

# Create root ssh directory
mkdir -p /root/.ssh
chmod 700 /root/.ssh

# Grab config from DigitalOcean metadata service
cat > /bin/do-init <<-EOF
#!/bin/sh
resize2fs /dev/vda
wget -T 5 http://169.254.169.254/metadata/v1/hostname    -q -O /etc/hostname
wget -T 5 http://169.254.169.254/metadata/v1/public-keys -q -O /root/.ssh/authorized_keys
hostname -F /etc/hostname
chmod 600 /root/.ssh/authorized_keys

fallocate -l 2G /swap
chmod 600 /swap
mkswap /swap
swapon /swap
echo "/swap swap swap defaults 0 0" >> /etc/fstab

rc-update del do-init default
exit 0
EOF

# Create do-init OpenRC service
cat > /etc/init.d/do-init <<-EOF
#!/sbin/openrc-run
depend() {
    need net.eth0
}
command="/bin/do-init"
command_args=""
pidfile="/tmp/do-init.pid"
EOF

# Make do-init and service executable
chmod +x /etc/init.d/do-init
chmod +x /bin/do-init

# Enable do-init service
rc-update add do-init default
rc-update add docker default