google cloud platform - Can not create gcp instance from machine image in a different project

Question

I have two GCP projects, projectA and projectB. In projectB, I have a machine image B-machine-image. My goal was to make a copy of the machine image in projectA. But since there is no way to copy the machine image from projectB to projectA directly, I thought I can create a instance in projectA using the machine image in projectB, then use the new instance in projectA to create a machine image locally.

I found a Google Doc for this: https://cloud.google.com/compute/docs/machine-images/create-instance-from-machine-image and followed the steps to first grant the service account in projectA admin role to the machine image B-machine-image in projectB, then run the command to make the instance like:

gcloud beta compute instances create my-new-instance --project=projectA --zone us-central1-b --source-machine-image projects/projectB/global/machineImages/B-machine-image --service-account 123456789000-compute@developer.gserviceaccount.com

and I am getting the error:

ERROR: (gcloud.beta.compute.instances.create) Could not fetch resource:

• Invalid value for field 'resource.networkInterfaces[0].network': 'projects/123456789000/global/networks/projectB-vpc'. The referenced network resource cannot be found.

In projectB, I do have a VPC called projectB-vpc.

What I do not understand is that in "projects/123456789000/global/networks/projectB-vpc", 123456789000 seems is for projectA as it is part of the email for projectA service account, while projectB-vpc is for projectB. In my command I have "projects/projectB/....", why the command replaced "projectB" with 123456789000?

Any idea where did I do wrong?

Thanks, Philip

Answer 1

As per the GCP documentation you can create VM using a machine image from a different project directly. Please note that, when you create a VM by using a machine image from a different project, you might not have access to the service account attached to that source project. In my reproduction steps I followed this steps:

1. Created an Multi-regional Machine Image

2. gcloud beta compute machine-images add-iam-policy-binding rhel-machine-image 
    --project=source-project 
    --member='serviceAccount:Source-compute@developer.gserviceaccount.com' 
    --role='roles/compute.admin'

3. Added the source project service account to destination project as iam.serviceAccountUser

4. gcloud beta compute instances create machine-image-vm     --project=destination-project --zone us-central1-a --source-machine-image projects/source-project/global/machineImages/rhel-machine-image --service-account Destination-compute@developer.gserviceaccount.com

On the last step I used destination project Compute Engine Default Service Account.

Created [https://www.googleapis.com/compute/beta/projects/destination-project/zones/us-central1-a/instances/machine-image-vm].
NAME              ZONE           MACHINE_TYPE  PREEMPTIBLE  INTERNAL_IP  EXTERNAL_IP     STATUS
machine-image-vm  us-central1-a  e2-medium                  x0.xxx.0.18  35.2x3.18x.x59  RUNNING