Make k8s_drain work when only one pod is present

changelogs/fragments/770-fix-k8s-drain-doesnt-wait-for-single-pod.yaml

@@ -0,0 +1,2 @@
+bugfixes:
+  - k8s_drain - Fix k8s_drain does not wait for single pod (https://github.com/ansible-collections/kubernetes.core/issues/769).

plugins/modules/k8s_drain.py

@@ -291,23 +291,25 @@ def _elapsed_time():
             return (datetime.now() - start).seconds
 
         response = None
-        pod = pods.pop()
+        pod = None
         while (_elapsed_time() < wait_timeout or wait_timeout == 0) and pods:
             if not pod:
-                pod = pods.pop()
+                pod = pods[-1]
             try:
                 response = self._api_instance.read_namespaced_pod(
                     namespace=pod[0], name=pod[1]
                 )
                 if not response:
                     pod = None
+                    del pods[-1]
                 time.sleep(wait_sleep)
             except ApiException as exc:
                 if exc.reason != "Not Found":
                     self._module.fail_json(
                         msg="Exception raised: {0}".format(exc.reason)
                     )
                 pod = None
+                del pods[-1]
             except Exception as e:
                 self._module.fail_json(msg="Exception raised: {0}".format(to_native(e)))
         if not pods: