Ansible playbook to get ssh host keys from Azure virtual machines

update-known-hosts.yml

---
- hosts: localhost
  gather_facts: no
  vars:
     home: "{{ lookup('env','HOME') }}"
  tasks:
  - name: Fetch SSH public keys
    shell: 'az vm run-command invoke --name {{item}} --command-id RunShellScript --scripts "cat /etc/ssh/ssh_host_ecdsa_key.pub" --query output[0].message | grep -o "ecdsa-sha2-nistp256 .*="'
    register: host_key
    with_items: "{{groups['all']|sort}}"

  - name: Import SSH public keys
    lineinfile:
      dest: "{{home}}/.ssh/known_hosts"
      line: "{{item.1}}.example.com,{{hostvars[item.1].private_ip}}{{(hostvars[item.1].public_ip is none)|ternary('', ',' + [hostvars[item.1].public_ip]|join(''))}} {{host_key.results[item.0].stdout}}"
    with_indexed_items: "{{groups['all']|sort}}"