Add webserver PodDisruptionBudget

chart/templates/webserver/webserver-poddisruptionbudget.yaml

@@ -0,0 +1,46 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+################################
+## Airflow Webserver PodDisruptionBudget
+#################################
+{{- if .Values.webserver.podDisruptionBudget.enabled }}
+kind: PodDisruptionBudget
+{{- if semverCompare ">= 1.21.x" (include "kubeVersion" .) }}
+apiVersion: policy/v1
+{{- else }}
+apiVersion: policy/v1beta1
+{{- end }}
+metadata:
+  name: {{ .Release.Name }}-webserver-pdb
+  labels:
+    tier: airflow
+    component: webserver
+    release: {{ .Release.Name }}
+    chart: {{ .Chart.Name }}
+    heritage: {{ .Release.Service }}
+{{- with .Values.labels }}
+{{ toYaml . | indent 4 }}
+{{- end }}
+spec:
+  selector:
+    matchLabels:
+      tier: airflow
+      component: webserver
+      release: {{ .Release.Name }}
+{{ toYaml .Values.webserver.podDisruptionBudget.config | indent 2 }}
+{{- end }}

chart/tests/test_pdb_webserver.py

@@ -0,0 +1,35 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+import unittest
+
+from tests.helm_template_generator import render_chart
+
+
+class WebserverPdbTest(unittest.TestCase):
+    def test_should_pass_validation_with_just_pdb_enabled_v1(self):
+        render_chart(
+            values={"webserver": {"podDisruptionBudget": {"enabled": True}}},
+            show_only=["templates/webserver/webserver-poddisruptionbudget.yaml"],
+        )  # checks that no validation exception is raised
+
+    def test_should_pass_validation_with_just_pdb_enabled_v1beta1(self):
+        render_chart(
+            values={"webserver": {"podDisruptionBudget": {"enabled": True}}},
+            show_only=["templates/webserver/webserver-poddisruptionbudget.yaml"],
+            kubernetes_version='1.16.0',
+        )  # checks that no validation exception is raised

chart/values.schema.json

@@ -1605,7 +1605,10 @@
                             "properties": {
                                 "maxUnavailable": {
                                     "description": "Max unavailable pods for scheduler.",
-                                    "type": "integer",
+                                    "type": [
+                                        "integer",
+                                        "string"
+                                    ],
                                     "default": 1
                                 }
                             }
@@ -2476,6 +2479,33 @@
                         }
                     }
                 },
+                "podDisruptionBudget": {
+                    "description": "Webserver pod disruption budget.",
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                        "enabled": {
+                            "description": "Enable pod disruption budget.",
+                            "type": "boolean",
+                            "default": false
+                        },
+                        "config": {
+                            "description": "Disruption budget configuration.",
+                            "type": "object",
+                            "additionalProperties": false,
+                            "properties": {
+                                "maxUnavailable": {
+                                    "description": "Max unavailable pods for webserver.",
+                                    "type": [
+                                        "integer",
+                                        "string"
+                                    ],
+                                    "default": 1
+                                }
+                            }
+                        }
+                    }
+                },
                 "extraNetworkPolicies": {
                     "description": "Additional NetworkPolicies as needed (Deprecated - renamed to `webserver.networkPolicy.ingress.from`).",
                     "type": "array",
@@ -3296,7 +3326,10 @@
                             "properties": {
                                 "maxUnavailable": {
                                     "description": "Max unavailable pods for PgBouncer.",
-                                    "type": "integer",
+                                    "type": [
+                                        "integer",
+                                        "string"
+                                    ],
                                     "default": 1
                                 }
                             }

chart/values.yaml

@@ -838,6 +838,14 @@ webserver:
     # Annotations to add to webserver kubernetes service account.
     annotations: {}
 
+  # Webserver pod disruption budget
+  podDisruptionBudget:
+    enabled: false
+
+    # PDB configuration
+    config:
+      maxUnavailable: 1
+
   # Allow overriding Update Strategy for Webserver
   strategy: ~