Google Cloud Deployment Manager: add instances to instance group via yaml configuration - google-cloud-platform

Question

I'm trying to create an unmanaged instanceGroup with several VM's in it via Deployment Manager Configuration (YAML file).
I can easily find docs about addInstances via Google API, but couldn't find docs about how to do this in a YAML file:
instances
instanceGroups
What properties should be included in instances/instanceGroup resource to make it work?

Answer 1

The YAML below will create a compute engine instance, create an unmanaged instance group, and add the instance to the group.
resources:
- name: instance-1
type: compute.v1.instance
properties:
zone: australia-southeast1-a
machineType: zones/australia-southeast1-a/machineTypes/n1-standard-1
disks:
- deviceName: boot
type: PERSISTENT
diskType: zones/australia-southeast1-a/diskTypes/pd-ssd
boot: true
autoDelete: true
initializeParams:
sourceImage: projects/debian-cloud/global/images/debian-9-stretch-v20180716
networkInterfaces:
- network: global/networks/default
accessConfigs:
- name: External NAT
type: ONE_TO_ONE_NAT
- name: ig-1
type: compute.v1.instanceGroup
properties:
zone: australia-southeast1-a
network: global/networks/default
- name: ig-1-members
action: gcp-types/compute-v1:compute.instanceGroups.addInstances
properties:
project: YOUR_PROJECT_ID
zone: australia-southeast1-a
instanceGroup: ig-1
instances: [ instance: $(ref.instance-1.selfLink) ]

Answer 2

There is no possibility right now, to do it with gcloud deployment manager.

Answer 3

This was tested and it seemed that while Google Deployment Manager was able to complete without issue having the following snippet:
{
"instances": [
{
"instance": string
}
]
}
it did not add the instances specified, but created the IGM.
However Terraform seems to be able to do it https://www.terraform.io/docs/providers/google/r/compute_instance_group.html

Answer 4

I think #mcourtney answer is correct.
I just had this scenario and i used python template with yaml config to add instances to an un-managed instance group.
Here is the snippet of resource definition in my python template :
{
'name': name + '-ig-members',
'action': 'gcp-types/compute-v1:compute.instanceGroups.addInstances',
'properties': {
'project': '<YOUR PROJECT ID>',
'zone' : context.properties['zone'], // Defined in config yaml
'instanceGroup': '<YOUR Instance Group name ( not url )>',
"instances": [
{
"instance": 'projects/<PROJECT ID>/zones/<YOUR ZONE>/instances/<INSTANCE NAME>'
}
]
}
}
Reference API is documented here :
https://cloud.google.com/compute/docs/reference/rest/beta/instanceGroups/addInstances
This is just an example. you can abstract all the hard coded things to either yaml configuration or variables at the top of python template.