GCE: Setting Environment Variables from Metadata - environment-variables

Question

I am using Packer to generate an image on Google Compute Engine, and Terraform to create the instance. I have set this metadata:
key: env_vars
value: export test=10
Packer is using a script with something like this inside:
curl "http://metadata.google.internal/computeMetadata/v1/project/attributes/env_vars?recursive=tru&alt=text" -H "Metadata-Flavor: Google" -o /tmp/env_vars.sh
source /tmp/env_vars.sh # or . /tmp/env_vars.sh
The problem is that when I create an instance using this image through Terraform the env variables are not available. That means, If I run printenv or echo $test, it is empty.
Even if I write a startup-script for the instance, it doesn't work.
But, if I run the same exact script inside the instance via SSH, it does work.
In all scenarios described above, the file env_vars.sh is created.
I just want to set the env vars from my metadata for any instance.
Any suggestion on how can I achieve this?
EDIT:
Here's the terraform code:
# create instance
resource "google_compute_instance" "default" {
count = 1
name = var.machine_name
machine_type = var.machine_type
zone = var.region_zone
tags = ["allow-http-ssh-rule"]
boot_disk {
initialize_params {
image = var.source_image
}
}
network_interface {
network = "default"
access_config {
// Ephemeral IP
}
}
}

Answer 1

I have reproduced your issue in my own project, and you are right it seems that exportdoes not work on the strat-up script.
I also tried creating a start-up script in a bucket but it does not work.
On the other hand I was able to set the env var in my project:
I’m using a debian-9 image, so, I edited the /etc/profile to add the env vars.
I use the following code to create my VM with env variables:
provider "google" {
project = "<<PROJECT-ID>>"
region = "us-central1"
zone = "us-central1-c"
}
resource "google_compute_instance" "vm_instance" {
name = "terraform-instance"
machine_type = "f1-micro"
boot_disk {
initialize_params {
image = "debian-cloud/debian-9"
}
}
network_interface {
# A default network is created for all GCP projects
network = "default"
access_config {
}
}
# defining metadata
metadata = {
foo = "bar"
}
metadata_startup_script = "echo ENVVAR=DEVELOPMENT2 >> /etc/profile"
}
After the creation of my instance I was able to see the correct values:
$ echo $ENVVAR
DEVELOPMENT2