[SOLVED] Ansible aws_ec2 plugin set ansible_host: from multiple private ips based on 'description:'

Issue

I have looked at this post, but it doesn't really help me.

Symptom

Using EC2 Dynamic Inventory, I am unable to configure the ansible_host: var to the private-ip-address: of a specific interface when there are two interfaces available with private-ip-address: on different subnets.

Reason for question

The two interfaces in use on the hosts are management and server-lan. The Ansible Control node can only access hosts via the management interface.

Note: I've simplified the code for reading and changed the host and IP details.

I have the following very simple example ec2_aws inventory file.

plugin: aws_ec2
regions:
  - us-west-x
filters:
  tag:Name: ec2-host-01
  instance-state-name: running
keyed_groups:
  # Add hosts to tag_Name_Value groups for each Name/Value tag pair
  - prefix: tag
    key: tags
hostnames:
  - tag:Name
compose:
  ansible_host: private-ip-address

My sample host has 2 Network interfaces management and server-lan, as identified in the description:.

{
    "_meta": {
        "hostvars": {
            "ec2-host-01": {
                .....
                "network_interfaces": [
                    {...
                         "description": "management",
                         "private_ip_addresses": [
                             {
                                 "primary": true,
                                 "private_dns_name": "ip-10-0-1-1.eu-west-x.compute.internal",
                                 "private_ip_address": "10.0.1.1"
                             }
                         ],
                    },
                    {...
                         "description": "server-lan",
                         "private_ip_addresses": [
                             {
                                 "primary": true,
                                 "private_dns_name": "ip-10-0-20-1.eu-west-x.compute.internal",
                                 "private_ip_address": "10.0.20.1"
                             }
                         ],
                    }
...
}

I'm not sure if this makes a difference, but both interfaces have primary: true.

This is the output I currently get from the ansible-inventory command. The ec2 plugin appears to randomly assign the ansible_host . Where as I need to set the ansible_host var to the IP address of the management interface. Currently, I am unable to specify the private-ip-address of the management interface.

{
    "_meta": {
        "hostvars": {
            "ec2-host-01": {
                "ami_launch_index": 0,
                "ansible_host": "10.0.20.1",       ## NB: This should be 10.0.1.1
                "architecture": "x86_64",
                "block_device_mappings": [
....

Here is the output of the ansible-inventory --graph --vars command:

  |  |--ec2-host-01
  |  |  |--{ansible_host = 10.0.20.1}
  ...............
  |  |  |--{network_interfaces = [{'attachment': {'attach_time': datetime.datetime(2022, 7, 13, 13, 45, 38, tzinfo=tzlocal()), 'attachment_id': 'eni-attach-xxxxxxxxxxxxxxxxx', 'delete_on_termination': False, 'device_index': 1, 'status': 'attached', 'network_card_index': 0}, 'description': 'server-lan', 'groups': [{'group_name': 'server_group', 'group_id': 'xxxxxxxxxxxxxxxxxxx'}], 'ipv6_addresses': [], 'mac_address': 'xx:xx:xx:xx:xx:xx', 'network_interface_id': 'eni-xxxxxxxxxxxxxxxxx', 'owner_id': '123456789123', 'private_dns_name': 'ip-10-0-20-1.eu-west-x.compute.internal', 'private_ip_address': '10.0.20.1', 'private_ip_addresses': [{'primary': True, 'private_dns_name': 'ip-10-0-20-1.eu-west-x.compute.internal', 'private_ip_address': '10.0.20.1'}], 'source_dest_check': True, 'status': 'in-use', 'subnet_id': 'subnet-management-xxxxxx', 'vpc_id': 'vpc-abc123xxxxxxxxxx', 'interface_type': 'interface'}, {'attachment': {'attach_time': datetime.datetime(2022, 7, 13, 13, 45, 38, tzinfo=tzlocal()), 'attachment_id': 'eni-attach-xxxxxxxxxxxxxxxxx', 'delete_on_termination': False, 'device_index': 0, 'status': 'attached', 'network_card_index': 0}, 'description': 'management', 'groups': [{'group_name': 'server_group', 'group_id': 'xxxxxxxxxxxxxxxxxxx'}], 'ipv6_addresses': [], 'mac_address': 'xx:xx:xx:xx:xx:xx', 'network_interface_id': 'eni-xxxxxxxxxxxxxxxxx', 'owner_id': '123456789123', 'private_dns_name': 'ip-10-0-1-1.eu-west-x.compute.internal', 'private_ip_address': '10.0.1.1', 'private_ip_addresses': [{'primary': True, 'private_dns_name': 'ip-10-0-1-1.eu-west-x.compute.internal', 'private_ip_address': '10.0.1.1'}], 'source_dest_check': True, 'status': 'in-use', 'subnet_id': 'subnet-lan-xxxxxxxxxxxxxx', 'vpc_id': 'vpc-abc123xxxxxxxxxx', 'interface_type': 'interface'}]}
  |  |  |--{private_dns_name = ip-10-0-20-1.eu-west-x.compute.internal}
  |  |  |--{private_dns_name_options = {'hostname_type': 'ip-name', 'enable_resource_name_dns_a_record': False, 'enable_resource_name_dns_aaaa_record': False}}
  |  |  |--{private_ip_address = 10.0.20.1}
  ...............
  |  |  |--{source_dest_check = True}
  |  |  |--{state = {'code': 16, 'name': 'running'}}
  |  |  |--{state_transition_reason = }
  ...............
  |  |  |--{usage_operation = RunInstances}
  |  |  |--{usage_operation_update_time = 2022-07-13 13:45:38+00:00}

Required Result

I need to be able to configure the aws_ec2.yml configuration file (possibly via the compose: key) to set the ansible_host: var as the private-ip-address of the management interface.

compose:
  # I need to set this var to:  10.0.1.1  eg: the management interface IP.
  ansible_host: private-ip-address ???????

β.εηοιτ.βε has already provided a solution to be able to retrieve the management and server-lan ip addresses during a playbook run (here), but this is different, as this is defining the inventory vars.

Solution

plugin: aws_ec2
cache: yes
regions:
  - eu-central-1
hostnames:
  - tag:Name
filters:
  instance-state-name:
    - running
compose:
  ansible_host: network_interfaces | selectattr('description', 'defined') | selectattr('description', '==', 'management') | map(attribute='private_ip_addresses') | map(attribute='private_ip_address')

Answered By - Markus

Answer Checked By - Mildred Charles (WPSolving Admin)