How to create a complex variable from an existing variable (not a clone)

[Cyril Scetbon]

Hi,

I'm using a lot of parameters when I instantiate an ec2 instance. I'd like to reuse the same configuration for all my instances and extend them depending on instances.

For example, my global variable is 

ec2_parameters:

  key_name: mykey

  instance_type: mytype

  image: ami-60a10117

  region: myregion

and in my playbook, I'd like to use the same ec2_parameters and to add some configuration depending on the instance I configure :

host: instance_type_1

  vars:

    ec2:

      "{{ ec2_parameters + dict(foo='bar') }}"

host: instance_type_2

  vars:

    ec2:

      "{{ ec2_parameters + dict(foo='toto') }}"

Is there a way to do that easily ?

Thanks