Create ec2 instance within vpc with two nics through ansible - amazon-ec2

Question

after a day of googling I decided to give up and ask here:
I'm still quite new to ansible and AWS, hence this question might lack background information which I'm happy to provide on request.
What I'm trying to achieve:
Write an Ansible playbook, which creates a new ec2 instance within my vpc.
This instance shall be provided with two new nics, eth0 and eth1. These nics should be associated with each one specific security group.
My playbook so far is built like this:
Create eth0
Create eth1
Create ec2 instance
My problem:
All documentation says I need to provide the eni-id of the interface I'd like to attach to my instance. I can't provide this, since the ids do not exist yet. The only thing I know is the name of the interfaces so I was trying to get the id of the interfaces separately, which also didn't work.
If I try to register the output of the creation of eth{0,1} in ansible, the whole output is stored and breaks the validation later when calling the variables in the section of the instance creation. Same with the extra step after the creation process.
More about the setup:
Running a VPC in AWS, hosts inside VPC are only accessible through VPN.
Running Ansible on macOS:
ansible --version
ansible [core 2.14.1]
config file = None
configured module search path = ['/Users/mg/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
ansible python module location = /usr/local/Cellar/ansible/7.1.0/libexec/lib/python3.11/site-packages/ansible
ansible collection location = /Users/mg/.ansible/collections:/usr/share/ansible/collections
executable location = /usr/local/bin/ansible
python version = 3.11.1 (main, Dec 23 2022, 09:40:27) [Clang 14.0.0 (clang-1400.0.29.202)] (/usr/local/Cellar/ansible/7.1.0/libexec/bin/python3.11)
jinja version = 3.1.2
libyaml = True
Playbook:
---
- name: Create ec2 instances
hosts: localhost
gather_facts: false
tasks:
# Block is a Group of Tasks combined together
- name: Get Info Block
block:
- name: Get Running instance Info
ec2_instance_info:
register: ec2info
- name: Print info
debug: var="ec2info.instances"
# By specifying always on the tag,
# I let this block to run all the time by module_default
# this is for security to net create ec2 instances accidentally
tags: ['always', 'getinfoonly']
- name: Create ec2 block
block:
- amazon.aws.ec2_vpc_net_info:
vpc_ids: vpc-XXXXXXXXXXXXXXXXX
- name: Create ec2 network interface eth0_lan
delegate_to: localhost
tags: ec2-create
amazon.aws.ec2_eni:
name: "eth0_lan_{{ vpc_hostname }}"
description: "eth0_lan_{{ vpc_hostname }}"
subnet_id: "{{ vpc_subnetid }}"
state: present
delete_on_termination: true
region: eu-central-1
security_groups: "sg-XXXXXXXXXXXXXXXXX"
- name: Get id of eth0
delegate_to: localhost
tags: ec2-create
amazon.aws.ec2_eni:
name: "eth0_lan_{{ vpc_hostname }}"
register: eth0
- name: Create ec2 network interface eth1_wan
delegate_to: localhost
tags: ec2-create
amazon.aws.ec2_eni:
name: "eth1_wan_{{ vpc_hostname }}"
description: "eth1_wan_{{ vpc_hostname }}"
subnet_id: "subnet-XXXXXXXXXXXXXXXXX"
state: present
delete_on_termination: true
region: eu-central-1
security_groups: 'sg-XXXXXXXXXXXXXXXXX'
- name: Get id of eth1
delegate_to: localhost
tags: ec2-create
amazon.aws.ec2_eni:
name: "eth1_wan_{{ vpc_hostname }}"
register: eth1
- name: Launch ec2 instances
tags: ec2-create
amazon.aws.ec2_instance:
name: "{{ vpc_hostname }}"
region: "eu-central-1"
key_name: "MyKey"
image_id: ami-XXXXXXXXXXXXXXXXX
vpc_subnet_id: "{{ vpc_subnetid }}"
instance_type: "{{ instance_type }}"
volumes:
- device_name: /dev/sda1
ebs:
volume_size: 30
delete_on_termination: true
network:
interfaces:
- id: "{{ eth0 }}"
- id: "{{ eth1 }}"
detailed_monitoring: true
register: ec2
delegate_to: localhost
# By specifying never on the tag of this block,
# I let this block to run only when explicitely being called
tags: ['never', 'ec2-create']
(If you're wondering about the tag-stuff, this comes from the tutorial I followed initially, credits: https://www.middlewareinventory.com/blog/ansible-aws-ec2/#How_Ansible_works_with_AWS_EC2_Setup_Boto_for_Ansible)
The execution of the ansible playbook breaks with this error:
An exception occurred during task execution. To see the full traceback, use -vvv. The error was: Invalid type for parameter NetworkInterfaces[1].NetworkInterfaceId, value: {'changed': True, 'interface': {'id': 'eni-XXXXXXXXXXXXXXXXX', 'subnet_id': 'subnet-XXXXXXXXXXXXXXXXX', 'vpc_id': 'vpc-XXXXXXXXXXXXXXXXX', 'description': 'somedescription', 'owner_id': 'XXXXXXXXXXXXXXXXX', 'status': 'available', 'mac_address': 'xx:xx:xx:xx:xx:xx, 'private_ip_address': 'xx.xx.xxx.xx', 'source_dest_check': True, 'groups': {'sg-XXXXXXXXXXXXXXXXX': 'SGNAME'}, 'private_ip_addresses': [{'private_ip_address': 'xx.xx.xxx.xx', 'primary_address': True}], 'name': 'eth1_wan_<fqdn>', 'tags': {'Name': 'eth1_wan_<fqdn>'}}, 'failed': False}, type: <class 'dict'>, valid types: <class 'str'>

Answer 1

So, my colleague and I managed to solve this: Use "{{ eth0.interface.id }}" instead. However, all instances continue to terminate themselves on creation. In AWS console: Client.InternalError. This is related to kms/ebs encryption which I turned on by default today.
It turned out, that I tried to use an asymmetrical customer-managed-key for default ebs encryption. As soon as I replaced this with a symmetrical one, it worked and the instances would start.