This script is mostly unmaintained and relies on the deprecated and
unmaintained `boto` library. Featuring it prominently in the docs
leads to many new users using it instead of the supported `aws_ec2`
inventory plugin.
Once your nodes are spun up, you'll probably want to talk to them again. With a cloud setup, it's best to not maintain a static list of cloud hostnames
in text files. Rather, the best way to handle this is to use the ec2 dynamic inventory script. See :ref:`dynamic_inventory`.
in text files. Rather, the best way to handle this is to use the aws_ec2 inventory plugin. See :ref:`dynamic_inventory`.
This will also dynamically select nodes that were even created outside of Ansible, and allow Ansible to manage them.
See :ref:`dynamic_inventory` for how to use this, then return to this chapter.
The plugin will also return instances that were created outside of Ansible and allow Ansible to manage them.
.._aws_tags_and_groups:
Tags And Groups And Variables
`````````````````````````````
When using the ec2 inventory script, hosts automatically appear in groups based on how they are tagged in EC2.
When using the inventory plugin, you can configure extra inventory structure based on the metadata returned by AWS.
For instance, you might use ``keyed_groups`` to create groups from instance tags::
plugin: aws_ec2
keyed_groups:
- prefix: tag
key: tags
For instance, if a host is given the "class" tag with the value of "webserver",
it will be automatically discoverable via a dynamic group like so::
You can then target all instances with a "class" tag where the value is "webserver" in a play::
- hosts: tag_class_webserver
tasks:
- ping
Using this philosophy can be a great way to keep systems separated by the function they perform.
In this example, if we wanted to define variables that are automatically applied to each machine tagged with the 'class' of 'webserver', 'group_vars'
in ansible can be used. See :ref:`splitting_out_vars`.
Similar groups are available for regions and other classifications, and can be similarly assigned variables using the same mechanism.
You can also use these groups with 'group_vars' to set variables that are automatically applied to matching instances. See :ref:`splitting_out_vars`.
@ -106,164 +106,6 @@ And technically, though there is no major good reason to do it, this also works
So in other words, you can use those variables in arguments/actions as well.
.._aws_example:
Inventory script example: AWS EC2
=================================
If you use Amazon Web Services EC2, maintaining an inventory file might not be the best approach, because hosts may come and go over time, be managed by external applications, or you might even be using AWS autoscaling. For this reason, you can use the `EC2 external inventory <https://raw.githubusercontent.com/ansible-collections/community.aws/main/scripts/inventory/ec2.py>`_ script.
You can use this script in one of two ways. The easiest is to use Ansible's ``-i`` command line option and specify the path to the script after marking it executable:
..code-block:: bash
ansible -i ec2.py -u ubuntu us-east-1d -m ping
The second option is to copy the script to `/etc/ansible/hosts` and `chmod +x` it. You must also copy the `ec2.ini <https://raw.githubusercontent.com/ansible-collections/community.aws/main/scripts/inventory/ec2.ini>`_ file to `/etc/ansible/ec2.ini`. Then you can run ansible as you would normally.
To make a successful API call to AWS, you must configure Boto (the Python interface to AWS). You can do this in `several ways <http://docs.pythonboto.org/en/latest/boto_config_tut.html>`_ available, but the simplest is to export two environment variables:
..code-block:: bash
export AWS_ACCESS_KEY_ID='AK123'
export AWS_SECRET_ACCESS_KEY='abc123'
You can test the script by itself to make sure your config is correct:
After a few moments, you should see your entire EC2 inventory across all regions in JSON.
If you use Boto profiles to manage multiple AWS accounts, you can pass ``--profile PROFILE`` name to the ``ec2.py`` script. An example profile might be:
..code-block:: text
[profile dev]
aws_access_key_id = <dev access key>
aws_secret_access_key = <dev secret key>
[profile prod]
aws_access_key_id = <prod access key>
aws_secret_access_key = <prod secret key>
You can then run ``ec2.py --profile prod`` to get the inventory for the prod account, although this option is not supported by ``ansible-playbook``.
You can also use the ``AWS_PROFILE`` variable - for example: ``AWS_PROFILE=prod ansible-playbook -i ec2.py myplaybook.yml``
Since each region requires its own API call, if you are only using a small set of regions, you can edit the ``ec2.ini`` file and comment out the regions you are not using.
There are other config options in ``ec2.ini``, including cache control and destination variables. By default, the ``ec2.ini`` file is configured for **all Amazon cloud services**, but you can comment out any features that aren't applicable. For example, if you don't have ``RDS`` or ``elasticache``, you can set them to ``False`` :
..code-block:: text
[ec2]
...
# To exclude RDS instances from the inventory, uncomment and set to False.
rds = False
# To exclude ElastiCache instances from the inventory, uncomment and set to False.
elasticache = False
...
At their heart, inventory files are simply a mapping from some name to a destination address. The default ``ec2.ini`` settings are configured for running Ansible from outside EC2 (from your laptop for example) -- and this is not the most efficient way to manage EC2.
If you are running Ansible from within EC2, internal DNS names and IP addresses may make more sense than public DNS names. In this case, you can modify the ``destination_variable`` in ``ec2.ini`` to be the private DNS name of an instance. This is particularly important when running Ansible within a private subnet inside a VPC, where the only way to access an instance is via its private IP address. For VPC instances, `vpc_destination_variable` in ``ec2.ini`` provides a means of using which ever `boto.ec2.instance variable <http://docs.pythonboto.org/en/latest/ref/ec2.html#module-boto.ec2.instance>`_ makes the most sense for your use case.
The EC2 external inventory provides mappings to instances from several groups:
Global
All instances are in group ``ec2``.
Instance ID
These are groups of one since instance IDs are unique.
e.g.
``i-00112233``
``i-a1b1c1d1``
Region
A group of all instances in an AWS region.
e.g.
``us-east-1``
``us-west-2``
Availability Zone
A group of all instances in an availability zone.
e.g.
``us-east-1a``
``us-east-1b``
Security Group
Instances belong to one or more security groups. A group is created for each security group, with all characters except alphanumerics, converted to underscores (_). Each group is prefixed by ``security_group_``. Currently, dashes (-) are also converted to underscores (_). You can change using the replace_dash_in_groups setting in ec2.ini (this has changed across several versions so check the ec2.ini for details).
e.g.
``security_group_default``
``security_group_webservers``
``security_group_Pete_s_Fancy_Group``
Tags
Each instance can have a variety of key/value pairs associated with it called Tags. The most common tag key is 'Name', though anything is possible. Each key/value pair is its own group of instances, again with special characters converted to underscores, in the format ``tag_KEY_VALUE``
When the Ansible is interacting with a specific server, the EC2 inventory script is called again with the ``--host HOST`` option. This looks up the HOST in the index cache to get the instance ID, and then makes an API call to AWS to get information about that specific instance. It then makes information about that instance available as variables to your playbooks. Each variable is prefixed by ``ec2_``. Here are some of the variables available:
- ec2_architecture
- ec2_description
- ec2_dns_name
- ec2_id
- ec2_image_id
- ec2_instance_type
- ec2_ip_address
- ec2_kernel
- ec2_key_name
- ec2_launch_time
- ec2_monitored
- ec2_ownerId
- ec2_placement
- ec2_platform
- ec2_previous_state
- ec2_private_dns_name
- ec2_private_ip_address
- ec2_public_dns_name
- ec2_ramdisk
- ec2_region
- ec2_root_device_name
- ec2_root_device_type
- ec2_security_group_ids
- ec2_security_group_names
- ec2_spot_instance_request_id
- ec2_state
- ec2_state_code
- ec2_state_reason
- ec2_status
- ec2_subnet_id
- ec2_tag_Name
- ec2_tenancy
- ec2_virtualization_type
- ec2_vpc_id
Both ``ec2_security_group_ids`` and ``ec2_security_group_names`` are comma-separated lists of all security groups. Each EC2 tag is a variable in the format ``ec2_tag_KEY``.
To see the complete list of variables available for an instance, run the script by itself:
flowerysong
4 years ago
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