Add check_mode support for k8s_drain module (#1086) (#1091)

This is a backport of PR #1086 as merged into main (d239adb).
SUMMARY

Closes #1037

added support for check_mode
Converted warnings into informational display when user has explicitly requested to delete daemontset-managed pods, unmanaged pods or pods with local storage


ISSUE TYPE


Feature Pull Request

COMPONENT NAME

k8s_drain

Reviewed-by: Bianca Henderson <beeankha@gmail.com>

tests/integration/targets/k8s_drain/templates/daemonset.yml.j2

@@ -0,0 +1,28 @@
+---
+apiVersion: apps/v1
+kind: DaemonSet
+metadata:
+  name: '{{ daemonset_name }}'
+spec:
+  affinity:
+    nodeAffinity:
+      requiredDuringSchedulingIgnoredDuringExecution:
+        nodeSelectorTerms:
+        - matchFields:
+          - key: metadata.name
+            operator: In
+            values:
+            - '{{ node_to_drain }}'
+  selector:
+    matchLabels:
+      drain: daemonset-pod
+  template:
+    metadata:
+      labels:
+        drain: daemonset-pod
+    spec:
+      containers:
+      - name: prometheus
+        image: prom/node-exporter
+        ports:
+        - containerPort: 80

tests/integration/targets/k8s_drain/templates/deployment.yml.j2

@@ -0,0 +1,40 @@
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: '{{ deployment_name }}'
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      drain: emptyDir
+  template:
+    metadata:
+      labels:
+        drain: emptyDir
+    spec:
+      metadata:
+        labels:
+          drain: emptyDir
+      affinity:
+        nodeAffinity:
+          requiredDuringSchedulingIgnoredDuringExecution:
+            nodeSelectorTerms:
+            - matchFields:
+              - key: metadata.name
+                operator: In
+                values:
+                - '{{ node_to_drain }}'
+      containers:
+        - name: busybox-container
+          image: busybox
+          command:
+            - /bin/sh
+            - -c
+            - while true;do date;sleep 5; done
+          volumeMounts:
+            - mountPath: /emptydir
+              name: emptydir
+      volumes:
+        - name: emptydir
+          emptyDir: {}

tests/integration/targets/k8s_drain/templates/pod1.yml.j2

@@ -0,0 +1,24 @@
+---
+apiVersion: v1
+kind: Pod
+metadata:
+  name: '{{ pod1_name }}'
+  labels:
+    drain: unmanaged-pod
+spec:
+  affinity:
+    nodeAffinity:
+      requiredDuringSchedulingIgnoredDuringExecution:
+        nodeSelectorTerms:
+          - matchFields:
+              - key: metadata.name
+                operator: In
+                values:
+                  - '{{ node_to_drain }}'
+  containers:
+    - name: busybox-container
+      image: busybox
+      command:
+        - /bin/sh
+        - -c
+        - while true;do date;sleep 5; done