GCP VM Startup script to determine VMs serving traffic

Question

I have a VM startup script which is supposed to show me which instance behind the load balancer is serving the traffic. Unfortionately the variable is not working correctly. Below is the simple script:

    #! /bin/bash
    sudo apt-get update
    sudo apt-get install apache2 -y
    sudo a2ensite default-ssl
    sudo a2enmod SSL
    sudo vm_hostname="$(curl -H "Metadata-Flavor:Google" \
    http://169.254.169.254/computeMetadata/v1/instance/hostname)"
    sudo echo "Page served from: $vm_hostname" | \
    tee /var/www/html/index.html

The result I see is simply the following in the browser window: Page served from:

Does anyone see a possible issue with the line calling the metadata?

Answer 1

You need to remove sudo from the six steps it will be like the script below.

vm_hostname="$(curl -H "Metadata-Flavor:Google" \ http://169.254.169.254/computeMetadata/v1/instance/hostname)"

Your final script will be:

#! /bin/bash
sudo apt-get update
sudo apt-get install apache2 -y
sudo a2ensite default-ssl
sudo a2enmod SSL

vm_hostname="$(curl -H "Metadata-Flavor:Google" \
http://169.254.169.254/computeMetadata/v1/instance/hostname)"

sudo echo "Page served from: $vm_hostname" | \
tee /var/www/html/index.html