when condition as per hostname in ansible task of azure devops pipeline

Question

Hostname usually look like vcs-200-01. So when ever the hostname has vcs or vhs task should be run. I have tried below task but its running on all VMs instead of running on specific Vms

- name:Exceute shell script
  become:yes
  become_user:root
  become_method:sudo
  command: sh /usr/..../example.sh
  when:("'vcs' in inventory_hostname_short") or ("'vhs' in inventory_hostname_short")

Answer 1

The problem is the quotation of the logical expressions inside the parenthesis. These expressions are not evaluated but taken as strings. A not empty string evaluates to True . This is the reason the condition is always True .

      when: ("'vcs' in inventory_hostname_short") or
            ("'vhs' in inventory_hostname_short")

The solution is simple. Remove the quotation. For example the task

    - debug:
        var: inventory_hostname_short
      when: ('vcs' in inventory_hostname_short) or
            ('vhs' in inventory_hostname_short)

and the inventory

shell> cat hosts
vcs-200-01
vhs-200-01
vxs-200-01

give

ok: [vcs-200-01] => 
  inventory_hostname_short: vcs-200-01
ok: [vhs-200-01] => 
  inventory_hostname_short: vhs-200-01
skipping: [vxs-200-01]

---

The origin of this mistake might be YAML parser asking for a quotation. For example

 when: 'vcs' in inventory_hostname_short

      when: ('vcs' in inventory_hostname_short)  # OK

The recommended quotation fixes the problem

      when: ("'vcs' in inventory_hostname_short")  # WRONG

so does also the closing in parenthesis

 when: ('vcs' in inventory_hostname_short) # OK

but not both parenthesis and quotation

 when: ("'vcs' in inventory_hostname_short") # WRONG

---

The or expression

      when: "'vcs' in inventory_hostname_short" or
            "'vhs' in inventory_hostname_short"

will produce a similar error and the same recommendation

      when: ('vcs' in inventory_hostname_short) or
            ('vhs' in inventory_hostname_short)

But here the recommended solution will not work and will produce the same error and the same recommendation

      when: "('vcs' in inventory_hostname_short) or
             ('vhs' in inventory_hostname_short)"

The logical expressions in or must be closed in parenthesis

 when: ('vcs' in inventory_hostname_short) or ('vhs' in inventory_hostname_short)

Then the condition may be optionally quoted

 when: "('vcs' in inventory_hostname_short) or ('vhs' in inventory_hostname_short)"