config.yaml

--- 
imports: 
  - path: manynodes.jinja
resources: 
  - 
    name: manynodes
    type: manynodes.jinja
    properties: 
      image: https://www.googleapis.com/compute/v1/projects/debian-cloud/global/images/debian-8-jessie-v20150818
      region: us-central1
      machine_type: n1-standard-1
      zones: 
        us-central1-f: 
          num_servers: 50
        us-central1-b: 
          num_servers: 50

manynodes.jinja

{% set INSTANCE_TEMPLATE =  env["name"] + "-it"  %}
{% set INSTANCE_GROUP =   env["name"] + "-ig" %}

resources:
- name: {{ INSTANCE_TEMPLATE }}
  type: compute.v1.instanceTemplate
  properties:
    project: {{ env["project"] }}
    properties:
      machineType: {{ properties["machine_type"] }} 
      disks:
      - deviceName: boot
        type: PERSISTENT
        boot: true
        autoDelete: true
        initializeParams:
          sourceImage: {{ properties["image"] }}
      networkInterfaces:
      - network: https://www.googleapis.com/compute/v1/projects/{{ env["project"] }}/global/networks/default
        accessConfigs:
        - name: External NAT
          type: ONE_TO_ONE_NAT
      serviceAccounts: 
      - email: "default"
        scopes: 
        - "https://www.googleapis.com/auth/compute"
      tags:
        items:
        - sometag
      metadata:
        items:
        - key: startup-script
          value: |
            #! /bin/bash
            apt-get update -y

{% for zone in properties["zones"] %}
# Instance Group Manager 
- name: {{ INSTANCE_GROUP + "-" + zone }}
  type: compute.v1.instanceGroupManager
  properties:
    zone: {{ zone }}
    targetSize: {{ properties["zones"][zone]["num_servers"] }}
    size: {{ properties["zones"][zone]["num_servers"] }}
    baseInstanceName: {{ env["name"] }}
    instanceTemplate: $(ref.{{ INSTANCE_TEMPLATE }}.selfLink)
{% endfor %}