Add delete_emptydir_data to drain delete_options (#322)

Add delete_emptydir_data to drain delete_options

SUMMARY
Adds delete_emptydir_data option to k8s_drain.delete_options to evict pods with an emptyDir volume attached.
ISSUE TYPE

Feature Pull Request

COMPONENT NAME
k8s_drain
ADDITIONAL INFORMATION
Be gentle, this is my first pull request 😨 
Basically adds the kubectl drain <node> --delete-emptydir-data feature, including tests.

Reviewed-by: Abhijeet Kasurde <None>
Reviewed-by: Jorn Eilander <None>
Reviewed-by: None <None>
Reviewed-by: None <None>

changelogs/fragments/322-Add-delete_emptydir_data-to-drain-delete_options.yaml

@@ -0,0 +1,3 @@
+---
+minor_changes:
+  - k8s_drain - Adds ``delete_emptydir_data`` option to ``k8s_drain.delete_options`` to evict pods with an ``emptyDir`` volume attached (https://github.com/ansible-collections/kubernetes.core/pull/322).

docs/kubernetes.core.k8s_drain_module.rst

@@ -137,6 +137,26 @@ Parameters
                         <div>Specify options to delete pods.</div>
                         <div>This option has effect only when <code>state</code> is set to <em>drain</em>.</div>
                 </td>
+            </tr>
+                                <tr>
+                    <td class="elbow-placeholder"></td>
+                <td colspan="1">
+                    <div class="ansibleOptionAnchor" id="parameter-"></div>
+                    <b>delete_emptydir_data</b>
+                    <a class="ansibleOptionLink" href="#parameter-" title="Permalink to this option"></a>
+                    <div style="font-size: small">
+                        <span style="color: purple">boolean</span>
+                    </div>
+                </td>
+                <td>
+                        <ul style="margin: 0; padding: 0"><b>Choices:</b>
+                                    <li><div style="color: blue"><b>no</b>&nbsp;&larr;</div></li>
+                                    <li>yes</li>
+                        </ul>
+                </td>
+                <td>
+                        <div>Continue even if there are pods using emptyDir (local data that will be deleted when the node is drained)</div>
+                </td>
             </tr>
             <tr>
                     <td class="elbow-placeholder"></td>

molecule/default/tasks/drain.yml

@@ -5,6 +5,7 @@
       drain_namespace: "drain"
       drain_daemonset_name: "promotheus-dset"
       drain_pod_name: "pod-drain"
+      drain_deployment_emptydir_name: "deployment-emptydir-drain"
 
   - name: Create {{ drain_namespace }} namespace
     k8s:
@@ -99,6 +100,61 @@
             - -c
             - while true;do date;sleep 5; done
 
+  - name: Create Deployment with an emptyDir volume.
+    k8s:
+      namespace: '{{ drain_namespace }}'
+      wait: yes
+      definition:
+        apiVersion: apps/v1
+        kind: Deployment
+        metadata:
+          name: '{{ drain_deployment_emptydir_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: c0
+                image: busybox
+                command:
+                - /bin/sh
+                - -c
+                - while true;do date;sleep 5; done
+                volumeMounts:
+                - mountPath: /emptydir
+                  name: emptydir
+              volumes:
+              - name: emptydir
+                emptyDir: {}
+
+  - name: Register emptyDir Pod name
+    k8s_info:
+      namespace: '{{ drain_namespace }}'
+      kind: Pod
+      label_selectors:
+      - "drain = emptyDir"
+    register: emptydir_pod_result
+    failed_when:
+    - emptydir_pod_result.resources | length != 1
+
   - name: Cordon node
     k8s_drain:
       state: cordon
@@ -167,14 +223,16 @@
       - drain_result is failed
       - '"cannot delete DaemonSet-managed Pods" in drain_result.msg'
       - '"cannot delete Pods not managed by ReplicationController, ReplicaSet, Job, DaemonSet or StatefulSet" in drain_result.msg'
+      - '"cannot delete Pods with local storage" in drain_result.msg'
 
-  - name: Drain node using ignore_daemonsets and force options
+  - name: Drain node using ignore_daemonsets, force, and delete_emptydir_data options
     k8s_drain:
       state: drain
       name: '{{ node_to_drain }}'
       delete_options:
         force: true
         ignore_daemonsets: true
+        delete_emptydir_data: true
         wait_timeout: 0
     register: drain_result
 
@@ -192,6 +250,14 @@
     register: _result
     failed_when: _result.resources
 
+  - name: assert that emptyDir pod was deleted
+    k8s_info:
+      namespace: '{{ drain_namespace }}'
+      kind: Pod
+      name: "{{ emptydir_pod_result.resources[0].metadata.name }}"
+    register: _result
+    failed_when: _result.resources | length != 0
+
   - name: Test drain idempotency
     k8s_drain:
       state: drain
@@ -199,6 +265,7 @@
       delete_options:
         force: true
         ignore_daemonsets: true
+        delete_emptydir_data: true
     register: drain_result
 
   - name: Check idempotency

plugins/modules/k8s_drain.py

@@ -64,6 +64,12 @@ options:
             - Ignore DaemonSet-managed pods.
             type: bool
             default: False
+        delete_emptydir_data:
+            description:
+            - Continue even if there are pods using emptyDir (local data that will be deleted when the node is drained).
+            type: bool
+            default: False
+            version_added: 2.3.0
         disable_eviction:
             description:
             - Forces drain to use delete rather than evict.
@@ -138,7 +144,7 @@ except ImportError:
     pass
 
 
-def filter_pods(pods, force, ignore_daemonset):
+def filter_pods(pods, force, ignore_daemonset, delete_emptydir_data):
     k8s_kind_mirror = "kubernetes.io/config.mirror"
     daemonSet, unmanaged, mirror, localStorage, to_delete = [], [], [], [], []
     for pod in pods:
@@ -153,7 +159,6 @@ def filter_pods(pods, force, ignore_daemonset):
             continue
 
         # Pod with local storage cannot be deleted
-        # TODO: support new option delete-emptydatadir in order to allow deletion of such pod
         if pod.spec.volumes and any(vol.empty_dir for vol in pod.spec.volumes):
             localStorage.append((pod.metadata.namespace, pod.metadata.name))
             continue
@@ -198,7 +203,14 @@ def filter_pods(pods, force, ignore_daemonset):
     # local storage
     if localStorage:
         pod_names = ",".join([pod[0] + "/" + pod[1] for pod in localStorage])
-        errors.append("cannot delete Pods with local storage: {0}.".format(pod_names))
+        if not delete_emptydir_data:
+            errors.append(
+                "cannot delete Pods with local storage: {0}.".format(pod_names)
+            )
+        else:
+            warnings.append("Deleting Pods with local storage: {0}.".format(pod_names))
+            for pod in localStorage:
+                to_delete.append((pod[0], pod[1]))
 
     # DaemonSet managed Pods
     if daemonSet:
@@ -349,8 +361,11 @@ class K8sDrainAnsible(object):
             # Filter pods
             force = self._drain_options.get("force", False)
             ignore_daemonset = self._drain_options.get("ignore_daemonsets", False)
+            delete_emptydir_data = self._drain_options.get(
+                "delete_emptydir_data", False
+            )
             pods, warnings, errors = filter_pods(
-                pod_list.items, force, ignore_daemonset
+                pod_list.items, force, ignore_daemonset, delete_emptydir_data
             )
             if errors:
                 _revert_node_patch()
@@ -467,6 +482,7 @@ def argspec():
                     terminate_grace_period=dict(type="int"),
                     force=dict(type="bool", default=False),
                     ignore_daemonsets=dict(type="bool", default=False),
+                    delete_emptydir_data=dict(type="bool", default=False),
                     disable_eviction=dict(type="bool", default=False),
                     wait_timeout=dict(type="int"),
                     wait_sleep=dict(type="int", default=5),