ansible :Connect to an host which is an output from previous play

Question

I am trying to connect to an host which is nothing but an cisco ios switch which I get by executing an powershell script. So basically the switch is output from an xml string from an powershell script. I am able to successfully receive the switch name from Ansible output. Now my question is how do I connect to the switch and see the details of the switch using show commands.

This my playbook:

hosts: localhost
connection: local
tasks:
  - name: Parse the XML output
    xml:
      xmlstring: "{{ hostvars[groups['win'][0]]['splat']['stdout'] }}"
      xpath: "/HostDiscovery/Host/Connection/NetworkDevice[Candidate='true' and  Uplink='false']/DeviceName"
      content: text
    register: data
  - debug:
      msg: "{{ item.DeviceName }}"
    with_items: "{{ data.matches }}"

This will give an output as follows

TASK [debug]
************************************************************************************************************************************************
task path: /etc/ansible/splat_executeps_script.yml:21 ok: [localhost] => (item={u'DeviceName': u'abc'}) => { "msg": "abc" }

where abc is the host to which I need to connect to in the subsequent task in the same playbook. I have tried writing something as below in the same yaml file

hosts: "{{ item.DeviceName }}"

connection: network_cli
tasks:
  - name: Show VLAN
    ios_command:
      commands:
        - show vlan brief | include {{id}}
        - show interfaces {{interface}} status
    register: vlan
  - debug: var=vlan.stdout_lines
    with_items: "{{ data.matches }}"

But this does not run and gives the below error:

META: ran handlers ERROR! The field 'hosts' has an invalid value, which includes an undefined variable. The error was: 'item' is undefined

The error appears to have been in '/etc/ansible/splat_executeps_script.yml': line 27, column 3, but may be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

hosts: "{{ item.DeviceName }}" ^ here

How can I correct the details, any help would be appreciated? Please note that the device which I am trying to connect in the subsequent task would be dynamically generated by the xml which is returned from PS script.

Answer 1

item only exists for the duration of the loop in that task. Use variables that you have registered.

add_host is one way to dynamically modify inventory. Then run the next play in your playbook against that group:

  - name: Add discovered switches to inventory
    add_host:
      name: "{{ item.DeviceName }}"
      groups: switch
    loop: "{{ data.matches }}"

hosts: switch

To not have to manage the inventory every time in your playbook, write a dynamic inventory script or plugin. This could be a variation on that PowerShell script that emits JSON instead, which Ansible can use as an inventory script. Examples are in the Ansible source code, under contrib/inventory.