when condition does not match with "ansible_host" Ansible 2.10? - ansible

Question

I try something very simple but it does not work:
I want to execute a task only, if two strings are the same:
hostname=1-Europe-ECV-Site2
ansible_host=1-Europe-ECV-Site2
This is the playbook:
- debug: var=hostname
- debug: var=ansible_host
- name: Gather a virtual machine info
vmware_guest_info:
hostname: '{{ vsphere_host }}'
username: '{{ vsphere_user }}'
password: '{{ vsphere_password }}'
validate_certs: false
datacenter: "{{ vsphere_datacenter }}"
name: "{{ hostname }}"
schema: vsphere
properties:
- guest.ipAddress
retries: 60
delay: 10
until: gather_vm_info.instance.guest.ipAddress is not none
register: gather_vm_info
delegate_to: localhost
when: ansible_host == hostname
I got this result, even if I can see by debugging, that both values are equal:
PLAY [Configure vyOS BGP LAN Router] *****************************************************************************************************************************************************
TASK [get_ip_vsphere : debug] ************************************************************************************************************************************************************
ok: [1-Europe-ECV-Site2] =>
hostname: 1-Europe-ECV-Site2
ok: [1-Europe-ECV-Site3] =>
hostname: 1-Europe-ECV-Site3
ok: [1-Europe-ECV-Site1-1] =>
hostname: 1-Europe-ECV-Site1-1
ok: [1-Europe-ECV-Site1-2] =>
hostname: 1-Europe-ECV-Site1-2
TASK [get_ip_vsphere : debug] ************************************************************************************************************************************************************
ok: [1-Europe-ECV-Site2] =>
ansible_host: 1-Europe-ECV-Site2
ok: [1-Europe-ECV-Site3] =>
ansible_host: 1-Europe-ECV-Site3
ok: [1-Europe-ECV-Site1-1] =>
ansible_host: 1-Europe-ECV-Site1-1
ok: [1-Europe-ECV-Site1-2] =>
ansible_host: 1-Europe-ECV-Site1-2
TASK [get_ip_vsphere : Gather a virtual machine info] ************************************************************************************************************************************
skipping: [1-Europe-ECV-Site2]
skipping: [1-Europe-ECV-Site3]
skipping: [1-Europe-ECV-Site1-1]
skipping: [1-Europe-ECV-Site1-2]
TASK [get_ip_vsphere : Gather a virtual machine info] ************************************************************************************************************************************
skipping: [1-Europe-ECV-Site2]
skipping: [1-Europe-ECV-Site3]
skipping: [1-Europe-ECV-Site1-1]
skipping: [1-Europe-ECV-Site1-2]
Question:
Why this condition does not match? Do I need to do something special if I want to use the build in variable ansible_host I use Ansible 2.10
EDIT:
The purpose of this playbook is to write only the discovered IP address into the inventory YAML file under host_vars, if it is not already defined. As you can see in my example, the ansible_host is equal to the hostname of the VM, if no IP address was detected.
For this I have to check if ansible_host == hostname and only then IP must be fetched and written into the YAML inventory file.
Another solution is to check if 192.168. is not included in "ansbile_host" and then execute the task:
when: "'192.168' in ansible_host"
But this also does not work!
What do I miss?

Answer 1

I don't think issue is with the ansible_host variable. It is because you are trying to match hostname with ansible_host, which should ideally match every time (looking at the debug output).
For example, when the task vmware_guest_info runs on 1-Europe-ECV-Site3:
hostname == ansible_host
Will be:
"1-Europe-ECV-Site3" == "1-Europe-ECV-Site3"
#=> True
Which is not what you want, even if it runs. If you want the task to run only when ansible_hostname matches 1-Europe-ECV-Site2, then the condition should be:
- name: Gather a virtual machine info
vmware_guest_info:
hostname: '{{ vsphere_host }}'
username: '{{ vsphere_user }}'
password: '{{ vsphere_password }}'
validate_certs: false
datacenter: "{{ vsphere_datacenter }}"
name: "{{ hostname }}"
schema: vsphere
properties:
- guest.ipAddress
retries: 60
delay: 10
until: gather_vm_info.instance.guest.ipAddress is not none
register: gather_vm_info
delegate_to: localhost
when: ansible_hostname == "1-Europe-ECV-Site2"

Answer 2

This solution works, I don't know why the other conditions does not fit:
---
- name: Gather a virtual machine info
vmware_guest_info:
hostname: '{{ vsphere_host }}'
username: '{{ vsphere_user }}'
password: '{{ vsphere_password }}'
validate_certs: false
datacenter: "{{ vsphere_datacenter }}"
name: "{{ hostname }}"
schema: vsphere
properties:
- guest.ipAddress
retries: 60
delay: 10
until: gather_vm_info.instance.guest.ipAddress is not none
register: gather_vm_info
delegate_to: localhost
when: "'192.168' not in ansible_host"
- name: Gather a virtual machine info
vmware_guest_info:
hostname: '{{ vsphere_host }}'
username: '{{ vsphere_user }}'
password: '{{ vsphere_password }}'
validate_certs: false
datacenter: "{{ vsphere_datacenter }}"
name: "{{ hostname }}"
schema: vsphere
properties:
- guest.ipAddress
retries: 60
delay: 10
until: gather_vm_info.instance.guest.ipAddress != "0.0.0.0"
register: gather_vm_info
delegate_to: localhost
when: "'192.168' not in ansible_host"
- debug: var=gather_vm_info.instance.guest.ipAddress
- name: Update IP
block:
- name: Add ansible_host IP to the YAML inventory file
delegate_to: localhost
lineinfile:
path: host_vars/{{ hostname }}.yml
line: " ansible_host: {{ gather_vm_info.instance.guest.ipAddress }}"
- name: Update dynamic ansible_host with new IP Address
set_fact:
ansible_host: "{{ gather_vm_info.instance.guest.ipAddress }}"
ansible_hostname: "{{ hostname }}"
when: "'192.168' not in ansible_host"

Answer 3

If you use IP address in when condition, it works. Hostname resolution did not happen in my case.
when: ansible_host == "xx.xx.xx.xx"