Terraform metadata_startup_script for GCP runs even though file is present to prevent it from running

Question

Been trying to trouble shoot this for two days. Not sure if it is a terraform or GCP issue. Or my code. I'm trying to create a VM and run some installs. It then creates a file in /var/run called flag.txt. If that file is present the startup script should exit and not run on reboots. I wrote a python script to write the date and time to the flag.txt file so I could test. However, everytime I reboot the time and date are updated in the flag.txt file showing that the startup script is running.

Here is my metadata_startup_script code

metadata_startup_script = <<-EOF

#!/bin/bash

if [ ! -f /var/run/flag.txt ];

then

sudo apt-get update

sudo apt-get install -y gcloud

echo '${local.script_content}' > /tmp/install_docker.sh

echo '${local.flag_content}' > /tmp/date_flag.py

chmod +x /tmp/install_docker.sh

chmod +x /tmp/date_flag.py

#Below command is just to show root is executing this script

#whoami >> /usr/bin/runner_id

bash /tmp/install_docker.sh

/usr/bin/python3 /tmp/date_flag.py

else

exit 0

fi

EOF

}

Here is the date_flag.py file that creates the flag.txt file

import datetime

current_datetime = datetime.datetime.now()
formatted_datetime = current_datetime.strftime("%Y-%m-%d_%H-%M-%S")
file_name = f"{formatted_datetime}.txt"
with open("/var/run/flag.txt", "w") as file:
    file.write("This file was created at: " + formatted_date

Any thoughts or suggestions are welcome. This is really driving me crazy.

Answer 1

So it turns out that /var/run is symbolically linked to /run which is created at startup. I fixed this by writing the flag.txt file to /etc.