I’m running an ansible playbook which calls an initial task that runs on localhost to add known_hosts ssh keys for all hosts returned by the inventory. This playbook runs fine if I use an explicit inventory list.

However, if I run the same playbook using aws_ec2.yml dynamic inventory and limit it to a single host or group it does not resolve localhost.

How can I configure an explicit localhost for ansible to resolve?

Here is what I run…

ansible-playbook build.yml -i ../inventories/DYNAMIC/aws_ec2.yml --limit HOST104

PLAY [Write key to known hosts] **********************************************************************************************************************************************************
skipping: no hosts matched

-----------------------------------------------------------------------------------------------------

Here is my playbook.


- name: Wait for connection to host
  hosts: localhost
  connection: local
  gather_facts: no
  become: true

  tasks:
    - name: Write Keys to known_hosts
      include_tasks: ../tasks/add-known-hosts.yml



I tried to call the aws_ec2.yml dynamically and specifically add localhost to the limit which does resolve the localhost. However, then it tries to write the ssh keys to known_hosts for ALL hosts instead of limiting to just a single host or group.

ansible-playbook build.yml -i ../inventories/DYNAMIC/aws_ec2.yml --limit HOST104:localhost

TASK [Write key to known hosts] *************************************************************************************************************************************************************
changed: [localhost -> 127.0.0.1] => (item=HOST100)
changed: [localhost -> 127.0.0.1] => (item=HOST101)
changed: [localhost -> 127.0.0.1] => (item=HOST102)
changed: [localhost -> 127.0.0.1] => (item=HOST103)
changed: [localhost -> 127.0.0.1] => (item=HOST104)


Here is my task to write keys to known_hosts...


- name: Write key to known hosts
  shell: "ssh-keyscan {{ hostvars[item].ansible_host }} >> ~/.ssh/known_hosts"
  when: hostvars[item].ansible_host is defined
  with_items: "{{ groups['all'] }}"