Switch Node Problem Detector to only pull IfNotPresent, make it configurable

roles/openshift_node_problem_detector/defaults/main.yaml

@@ -21,6 +21,7 @@ openshift_node_problem_detector_image_version: "{{ openshift_node_problem_detect
 # node_problem_detector daemonset setup
 openshift_node_problem_detector_daemonset_name: node-problem-detector
 openshift_node_problem_detector_daemonset_template_file: templates/node-problem-detector-daemonset.yaml.j2
+openshift_node_problem_detector_image_pull_policy: IfNotPresent
 
 # node_problem_detector service account setup
 openshift_node_problem_detector_service_account: node-problem-detector

roles/openshift_node_problem_detector/tasks/install.yaml

@@ -1,4 +1,9 @@
 ---
+- name: validate openshift_node_problem_detector_image_pull_policy variable
+  fail:
+    msg: "openshift_node_problem_detector_image_pull_policy must be one of Always, Never, IfNotPresent. Got {{ openshift_node_problem_detector_image_pull_policy }}"
+  when: openshift_node_problem_detector_image_pull_policy not in ['Always', 'Never', 'IfNotPresent']
+
 - name: create Node Problem Detector service account
   oc_serviceaccount:
     name: "{{ openshift_node_problem_detector_service_account }}"

roles/openshift_node_problem_detector/templates/node-problem-detector-daemonset.yaml.j2

@@ -22,7 +22,7 @@ spec:
               apiVersion: v1
               fieldPath: spec.nodeName
         image: {{ openshift_node_problem_detector_image_prefix }}node-problem-detector:{{ openshift_node_problem_detector_image_version }}
-        imagePullPolicy: Always
+        imagePullPolicy: {{ openshift_node_problem_detector_image_pull_policy }}
         name: {{ openshift_node_problem_detector_daemonset_name }}
         resources: {}
         securityContext: