Unable to pass ec2 variable from one ansible host to another

[deepak.d...@gmail.com]

I want to pass "private_dns_name" of my newly created ec2 instances to some other host in my ansible play book. I have tried using set_fact module to define the variable but no luck! This is ansible playbook entries for host1

Enter code here...

- name: new EC2 instance
   hosts: host1   
  tasks:
    - name: Launch the new EC2 Instance
      ec2:
       aws_access_key: "{{ aws_id }}"
       aws_secret_key: "{{ aws_key }}"
       group_id: "{{ security_group_id }}"
       instance_type: "{{ instance_type }}"
       image: "{{ image }}"
       key_name: "{{ ssh_keyname }}"
       wait: yes
       wait_timeout: 900
       region: "{{ region }}"
       count: 1
       instance_tags:
         Name: Prod-Engineering
      register: ec2
    - name: Register public DNS fact
      set_fact: public_dns= "{{ item.private_dns_name }}"
      with_items: ec2.instances  

    - debug: var=hostvars

- hosts: host2
   become: yes
   tasks:
    - command: ipa host-add "{{ hostvars['host1']['public_dns'] }}" --password=xxxxx
 But i am getting "'ansible.vars.hostvars.HostVars object' has no attribute" error. Every try of mine is failing and i am stuck with this issue. Would really appreciate if some one can help with this. I am using Ansible 2.1.1.0

Thanks, Deepak