cloud-init

#!/bin/sh

# exit on failure
set -e

# exit on unassigned variable
set -u

# variables
USER_DATA_FILE=${USER_DATA_FILE:-/var/lib/cloud/user-data}
SSH_AUTHORIZED_KEYS_SRC=${SSH_AUTHORIZED_KEYS_SRC:-/var/lib/cloud/ssh.pub}
SSH_AUTHORIZED_KEYS_DST=${SSH_AUTHORIZED_KEYS_DST:-/root/.ssh/authorized_keys}

# configure SSH access for root user
if [ -f "${SSH_AUTHORIZED_KEYS_SRC}" ]; then
	if [ -f "${SSH_AUTHORIZED_KEYS_DST}" ]; then
		echo "SSH public key file ${SSH_AUTHORIZED_KEYS_DST} already exists"
		echo "Exit to avoid overwrite it in case it was mounted RW using 'docker run --volume'"

		# return EACCES (Permission denied) to systemd
		exit 13
	fi

	install \
		--verbose \
		--mode 0700 \
		--owner root \
		--group root \
		--directory \
		/root/.ssh

	install \
		--verbose \
		--mode 0600 \
		--owner root \
		--group root \
		${SSH_AUTHORIZED_KEYS_SRC} ${SSH_AUTHORIZED_KEYS_DST}
fi

# run cloud-init script and send output to the same log file as the *real* cloud-init service
if [ -f "${USER_DATA_FILE}" ]; then
	/bin/sh -c ${USER_DATA_FILE} 2>&1 | tee -a /var/log/cloud-init-output.log
else
	echo "User-data script ${USER_DATA_FILE} does not exists" >&2

	# return ENOENT (No such file or directory) to systemd
	exit 2
fi