In order for GCP to import ssh key's on 1.2.1 image the ssh and ssh-import-id modules need to be loaded. This does not allow GCE to create new users, but it will allow GCE to import SSH keys for users created on the instance. This is required to access newly created GCE instances otherwise an authorized key cannot be set for the vyos user.
Required cloud-init modules for function :
```
cloud_init_modules:
- ssh
# The modules that run in the 'config' stage
cloud_config_modules:
- vyos
- ssh-import-id
# The modules that run in the 'final' stage
cloud_final_modules:
- runcmd
```