renaming hosts

[Joe]

I'm fairly new to ansible, so I'm still learning it.  Please bare with me.   I have a variable file that defines maps current hostnames of devices to new hostnames.  I'm trying to write a playbook that will re the variable file and change the hostnames of the devices.  So far I haven't had any luck, can some one tell me where I'm going wrong with this?  

The variable file and play book are pasted below

[joec@automation change_hostname]# cat hostname.yml

---

  - host: test13

    newhostname: test-switch1

  - host: jnpr-ans-test

    newhostname: test-switch2

[joec@automation change_hostname]# cat change_hostname.yml

---

- name: Examples of juniper_junos_command

  hosts: juniper

  gather_facts: no

  tasks:

    - include_vars:

        file: hostname.yml

        name: newnames

    - name: Get Facts.

      junos_facts:

        gather_subset: all

      register: facts

    - name: Rename device

      junos_facts:

        hostname: "{{ newnames.namehostname }}"

        when: facts.ansible_facts.ansible_net_hostname == newnames.host

        loop: "{{ newnames }}"