How to do it...

1. Create a new file inside the group_vars directory called network.yml:

$ cat group_vars/network.yml

---
ntp_servers:
  - 172.20.1.1
  - 172.20.2.1

2. Create a new templates directory and create a new ios_basic.j2 file with the following content:

$ cat templates/ios_basic.j2
hostname {{ hostname }}
!
{% for server in ntp_servers %}
ntp {{ server }}
{% endfor %}
!

3. Create a new junos_basic.j2 file within the templates directory with the following content:

$ cat templates/junos_basic.j2
set system host-name {{ hostname }}
{% for server in ntp_servers %}
set system ntp server {{ server }}
{% endfor %}

4. Create a new playbook called ansible_jinja2.yml with the following content:

---
  - name: Generate Cisco config from Jinja2
    hosts: localhost
    gather_facts: no
    tasks:
      - name: Create Configs Directory
        file: path=configs state=directory

  - name: Generate Cisco config from Jinja2
    hosts: cisco
    gather_facts: no
    tasks:
      - name: Generate Cisco Basic Config
        template:
          src: "templates/ios_basic.j2"
          dest: "configs/{{inventory_hostname}}.cfg"
        delegate_to: localhost

  - name: Generate Juniper config from Jinja2
    hosts: juniper
    gather_facts: no
    tasks:
      - name: Generate Juniper Basic Config
        template:
          src: "templates/junos_basic.j2"
          dest: "configs/{{inventory_hostname}}.cfg"
        delegate_to: localhost

5. Run the Ansible playbook as shown here:

$ ansible-playbook -i hosts ansible_jinja2.yml