Ansible role: creating EC2 instances

Motivation

This role simplifies the process of creating EC2 instances with Ansible by reducing the amount of input you'd normally have to feed the ec2_* modules with. This is achieved by setting default values once, in defaults/main.yml, that are used whenever you don't explicitly specify a required setting. On top of that, there are some convenience functions like choosing the subnet with the most free IP addresses or selecting the newest operating system image.

Requirements

• Ansible 2.7
• boto3
• Jinja 2.10
  • add jinja2_native = true to your ansible.cfg

There are (breaking) incompatiblities with versions lower than listed above. Using

pip install --user --upgrade ansible boto3 jinja2

will set you up just fine.

Authorization

If you're not using IAM role privileges you have to set aws_access_key and aws_secret_key in a pre-task when using this role. The preferred way is that you create a vault and include that in your play. Don't make a habit of hard-coding credentials.

Usage

This repository is meant to be used as submodule from within your Ansible project:

git submodule add https://github.com/generaliinformatik/ansible_role_ec2.git roles/ec2

Set the appropriate default values for your AWS environment in defaults/main.yml.

Example plays

A simple "hello world"-style example for an Ansible play using this role looks like this:

- hosts: localhost
  vars:
    instance_configuration:     # the configuration dictionary
      myinstance:               # this name can be freely chosen
        name: MYINSTANCENAME    # this name will appear in the 'Name' tag
  pre_tasks:
    - name: set AWS credentials
      set_fact:
        aws_access_key: "foo"   # For demonstration purposes only - hard-coding
        aws_secret_key: "bar"   # credentials is a bad practice.
  roles:
    - ec2

This will create an instance named MYINSTANCENAME based on the default settings as defined in defaults/main.yml.

A more elaborate example using more options:

- hosts: localhost
  vars:
    instance_configuration:
      instance1:
        name: SERVER01
        instance_type: m4.large
        root_volume_size: 60         # value in GiB
      instance2:
        name: SERVER02
        instance_type: m4.4xlarge
        root_volume_size: 40         # value in GiB
        additional_volumes:
          - device_name: /dev/sdb
            volume_type: gp2
            volume_size: 100         # value in GiB
  pre_tasks:
   - name: get AWS credentials from vault
      include_vars:  # aws_access_key, aws_secret_key
        file: /etc/ansible/aws_vault.yml
  roles:
    - ec2

You can check tasks/launch_ec2.yml to see all the options that are passed to ec2_instance; they can all be used in the instance_configuration dictionary.

License

MIT © 2019 Generali Deutschland Informatik Services GmbH