for i in $(seq 1 ${max_retries}); do
    gcloud compute instances get-serial-port-output ${target_vm_name} --zone=${target_vm_zone} > startup-script-output.txt 2>&1;
    
    if grep -q 'SCRIPT: COMPLETE' startup-script-output.txt; 
    then 
        rm startup-script-output.txt;
        break; 
    fi; 

    sleep ${retry_delay}; 
done