Ansible: Dynamic Inventory (using the AWS EC2 External Inventory Script)

Where hosts can appear and disappear (e.g. with AWS ASGs) the EC2 external inventory script (ec2.py) comes in useful.

All you need to do is to export your AWS keys as environment variables and ec2.py is good.

ec2.ini options

The EC2 inventory output can become very large. To manage its size, you can configure which groups should be created using ec2.ini options. E.g.

Note on how these are created:

  • format is tag_KEY_VALUE
  • special characters are changed to an underscore

E.g. with a NAME of my instance name we would get a tag of  tag_NAME_my_instance_name.

 

These inikeys are read in ec2.py. E.g.

See also:

https://github.com/ansible/ansible/blob/devel/contrib/inventory/ec2.py#L482

and

https://docs.ansible.com/ansible/2.6/user_guide/intro_dynamic_inventory.html#example-aws-ec2-external-inventory-script

 

 

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