How can I run an Ansible playbook without hosts specificed? - ansible

Question

I'm writing a playbook that spins up X number of EC2 AWS instances then just installs some software on them (apt packages and pip modules). When I run my playbook, it executes the shell commands on my local system because Ansible won't run unless I specify a host and I put localhost.
In the playbook, I've tried specifying "hosts: all" at the top-level, but this just makes the playbook run for a second without doing anything.
playbook.yml
- name: Spin up spot instances
hosts: localhost
connection: local
vars_files: ansible-vars.yml
tasks:
- name: create {{ spot_count }} spot instances with spot_price of ${{ spot_price }}
local_action:
module: ec2
region: us-east-2
spot_price: '{{ spot_price }}'
spot_wait_timeout: 180
keypair: My-keypair
instance_type: t3a.nano
image: ami-0f65671a86f061fcd
group: Allow from Home
instance_initiated_shutdown_behavior: terminate
wait: yes
count: '{{ spot_count }}'
register: ec2
- name: Wait for the instances to boot by checking the ssh port
wait_for: host={{item.public_ip}} port=22 delay=15 timeout=300 state=started
with_items: "{{ ec2.instances }}"
- name: test whoami
args:
executable: /bin/bash
shell: whoami
with_items: "{{ ec2.instances }}"
- name: Update apt
args:
executable: /bin/bash
shell: apt update
become: yes
with_items: "{{ ec2.instances }}"
- name: Install Python and Pip
args:
executable: /bin/bash
shell: apt install python3 python3-pip -y
become: yes
with_items: "{{ ec2.instances }}"
- name: Install Python modules
args:
executable: /bin/bash
shell: pip3 install bs4 requests
with_items: "{{ ec2.instances }}"
ansible-vars.yml
ansible_ssh_private_key_file: ~/.ssh/my-keypair.pem
spot_count: 1
spot_price: '0.002'
remote_user: ubuntu
The EC2 instances get created just fine and the "wait for SSH" task works, but the shell tasks get run on my local system instead of the remote hosts.
How can I tell Ansible to connect to the EC2 instances without using a hosts file since we're creating them on the fly?

Answer 1

Can you try this if it works.
- name: test whoami
args:
executable: /bin/bash
shell: whoami
delegate_to: "{{ item }}"
with_items: "{{ ec2.instances }}"