kubespray/roles/kubernetes/preinstall/tasks/vsphere-credential-check.yml

- name: check vsphere environment variables
  fail:
    msg: "{{ item.name }} is missing"
  when: item.value is not defined or item.value == ''
  with_items:
    - name: vsphere_vcenter_ip
      value: "{{ vsphere_vcenter_ip }}"
    - name: vsphere_vcenter_port
      value: "{{ vsphere_vcenter_port }}"
    - name: vsphere_user
      value: "{{ vsphere_user }}"
    - name: vsphere_password
      value: "{{ vsphere_password }}"
    - name: vsphere_datacenter
      value: "{{ vsphere_datacenter }}"
    - name: vsphere_datastore
      value: "{{ vsphere_datastore }}"
    - name: vsphere_working_dir
      value: "{{ vsphere_working_dir }}"
    - name: vsphere_insecure
      value: "{{ vsphere_insecure }}"