Improve error message for pod disruption budget when draining a node (#798) (#815)

This is a backport of PR #798 as merged into main (52f2cb5).
SUMMARY
Closes #797 .
The error message "Too Many Requests" is confusing and is changed to a more meaningful message:
TASK [Drain node] *************************************************************************
Montag 25 November 2024  09:20:28 +0100 (0:00:00.014)       0:00:00.014 ******* 
fatal: [host -> localhost]: FAILED! => {"changed": false, "msg": "Failed to delete pod kube-public/draintest-6b84677b99-9jf7m due to: Cannot evict pod as it would violate the pod's disruption budget."}


The new task output would allow to deal with a pod disruption budget with the retries/until logic in a more controlled way:
---
- hosts: "{{ target }}"
  serial: 1
  gather_facts: false
  tasks:
    - name: Drain node
      kubernetes.core.k8s_drain:
        kubeconfig: "{{ kubeconfig_path }}"
        name: "{{ inventory_hostname }}"
        delete_options:
          ignore_daemonsets: true
          delete_emptydir_data: true
          wait_timeout: 100
          disable_eviction: false
          wait_sleep: 1
      delegate_to: localhost
      retries: 10
      delay: 5
      until: drain_result is success or 'disruption budget' not in drain_result.msg
      register: drain_result

ISSUE TYPE


Feature Pull Request

COMPONENT NAME
k8s_drain

changelogs/fragments/798-drain-pdb-error-message.yaml

@@ -0,0 +1,2 @@
+minor_changes:
+  - k8s_drain - Improve error message for pod disruption budget when draining a node (https://github.com/ansible-collections/kubernetes.core/issues/797).

plugins/modules/k8s_drain.py

@@ -143,6 +143,7 @@ result:
 """
 
 import copy
+import json
 import time
 import traceback
 from datetime import datetime
@@ -187,6 +188,17 @@ except ImportError:
         HAS_EVICTION_API = False
 
 
+def format_dynamic_api_exc(exc):
+    if exc.body:
+        if exc.headers and exc.headers.get("Content-Type") == "application/json":
+            message = json.loads(exc.body).get("message")
+            if message:
+                return message
+        return exc.body
+    else:
+        return "%s Reason: %s" % (exc.status, exc.reason)
+
+
 def filter_pods(pods, force, ignore_daemonset, delete_emptydir_data):
     k8s_kind_mirror = "kubernetes.io/config.mirror"
     daemonSet, unmanaged, mirror, localStorage, to_delete = [], [], [], [], []
@@ -336,7 +348,7 @@ class K8sDrainAnsible(object):
                 if exc.reason != "Not Found":
                     self._module.fail_json(
                         msg="Failed to delete pod {0}/{1} due to: {2}".format(
-                            namespace, name, exc.reason
+                            namespace, name, to_native(format_dynamic_api_exc(exc))
                         )
                     )
             except Exception as exc: