Allow role to run without Intel Virtualisation Technology (VT)

While this provides better VM performance, it may not be available in
certain environments.

Author: markgoddard

README.md

@@ -29,6 +29,11 @@ should be a dict containing the following items:
   supported.
 - `bridge` The name of the bridge interface for this network.
 
+`libvirt_host_require_vt`is whether to require that Intel Virtualisation
+Technology (VT) is enabled in order to run this role. While this provides
+better VM performance, it may not be available in certain environments. The
+default value is `true`.
+
 Dependencies
 ------------
 

defaults/main.yml

@@ -17,3 +17,8 @@ libvirt_host_pools: []
 # supported.
 # bridge: The name of the bridge interface for this network.
 libvirt_host_networks: []
+
+# Whether to require that Intel Virtualisation Technology (VT) is enabled in
+# order to run this role. While this provides better VM performance, it may not
+# be available in certain environments.
+libvirt_host_require_vt: true

tasks/validate.yml

@@ -5,9 +5,20 @@
   failed_when: False
   register: result
 
+- name: Notify if Virtualization Technology (VT) is disabled
+  debug:
+    msg: >
+      Virtualization Technology (VT) is currently disabled. Please enable VT
+      before running this role again.
+  when:
+    - not libvirt_host_require_vt | bool
+    - result.rc != 0
+
 - name: Fail if Virtualization Technology (VT) is disabled
   fail:
     msg: >
       Virtualization Technology (VT) is currently disabled. Please enable VT
       before running this role again.
-  when: result.rc != 0
+  when:
+    - libvirt_host_require_vt | bool
+    - result.rc != 0