Ansible: Trying to create multiple EC2 instances in multiple regions in one shot

Keep in mind that Ansible is a "plugable" system, so it's really easy to customize it for your self. Sometimes it's even easier and faster than trying to find a workaround by using "native" modules.

In your case you can easily write your own custom lookup_plugin that would search for a correct subnet.

For example:

1. Create a folder called lookup_plugins in your main folder.
2. Create a file (if you do not have one) called ansible.cfg

[defaults]
lookup_plugins = lookup_plugins

Create a file in lookup_plugins called subnets.py

import boto.vpc
class LookupModule(object):
    def __init__(self, basedir=None, **kwargs):
        self.basedir = basedir
        self.plugin_name = 'subnets'
    def run(self, regions, variable=None, **kwargs):
        if not isinstance(regions, list):
            regions = [regions]
        for region in regions:
            return [boto.vpc.connect_to_region(region).get_all_subnets()[0].id]

The above simple code would look for a subnet in a given region. Of course you can customize it however you want.

Then in your playbook reference this plugin to find correct subnet:

Example:

- hosts: localhost
  gather_facts: no
  tasks:
    - name: Start instance
      debug: msg="Starting instance {{ item.ami }} in {{ item.region }} in {{ item.subnet }}"
      with_items:
        - region: us-west-1
          name: ss12
          ami: ami-b33dccf7  
          subnet: "{{ lookup('subnets', 'us-west-1') }}"
        - region: ap-northeast-1
          name: ss21
          ami: ami-9e5cff9e  
          subnet: "{{ lookup('subnets', 'ap-northeast-1') }}"
        - region: eu-west-1
          name: ss32
          ami: ami-7c4b0a0b 
          subnet: "{{ lookup('subnets', 'ap-northeast-1') }}"

In your case you would probably need to reference the correct AMI and associated Region .

if you still want to do this without help from another module you can calculate the modulo '%' of the servers and the subnets length:

"{{subnets[item.0 | int % subnets | length | int].aws_ec2_subnets}}"

example code

vars:

subnets:
  - {zone: "us-east-1a", aws_ec2_subnets: 'subnet-123'}
  - {zone: "us-east-1b", aws_ec2_subnets: 'subnet-456'}
  - {zone: "us-east-1d", aws_ec2_subnets: 'subnet-789'}

server_list:
  - server1
  - server2
  - server3

task:

- name: Create new ec2 instance
  ec2:
    profile: "{{aws_profile}}"
    key_name: "{{aws_key_name}}"
    group_id: "{{aws_security_group}}"
    instance_type: "{{aws_instance_type}}"
    image: "{{aws_ami}}"
    region: "{{region}}"
    exact_count: "1"
    #instance_profile_name: none
    wait: yes
    wait_timeout: 500
    volumes: "{{volumes}}"
    monitoring: no
    vpc_subnet_id: "{{subnets[item.0 | int % subnets | length | int].aws_ec2_subnets}}"
    assign_public_ip: no
    tenancy: default
    termination_protection: yes
    instance_tags:
      App: "{{app_name}}"
      Environment: "{{environment_type}}"
      Platform: "{{platform_name}}"
      Name: "{{item.1}}"
    count_tag:
      App: "{{app_name}}"
      Environment: "{{environment_type}}"
      Platform: "{{platform_name}}"
      Name: "{{item.1}}"
  register: ec2_new_instance
  with_indexed_items:
    - "{{server_list}}"