Merge pull request #1885 from somaz94/feat/chart-pod-disruption-budget

feat: add opt-in PodDisruptionBudget to the Helm chart

charts/descheduler/README.md

@@ -63,6 +63,10 @@ The following table lists the configurable parameters of the _descheduler_ chart
 | `deschedulingInterval`              | If using kind:Deployment, sets time between consecutive descheduler executions.                                       | `5m`                                      |
 | `replicas`                          | The replica count for Deployment                                                                                      | `1`                                       |
 | `leaderElection`                    | The options for high availability when running replicated components                                                  | _see values.yaml_                         |
+| `podDisruptionBudget.enabled`       | If `true` and `kind` is `Deployment`, create a PodDisruptionBudget for the descheduler                                | `false`                                   |
+| `podDisruptionBudget.minAvailable`  | Minimum descheduler pods that must stay available (mutually exclusive with `maxUnavailable`)                          | `1`                                       |
+| `podDisruptionBudget.maxUnavailable`| Maximum descheduler pods that can be unavailable (mutually exclusive with `minAvailable`)                             | `""`                                      |
+| `podDisruptionBudget.annotations`   | Annotations to add to the PodDisruptionBudget                                                                         | `{}`                                      |
 | `cmdOptions`                        | The options to pass to the _descheduler_ command                                                                      | _see values.yaml_                         |
 | `priorityClassName`                 | The name of the priority class to add to pods                                                                         | `system-cluster-critical`                 |
 | `rbac.create`                       | If `true`, create & use RBAC resources                                                                                | `true`                                    |

charts/descheduler/templates/poddisruptionbudget.yaml

@@ -0,0 +1,30 @@
+{{- if and (eq .Values.kind "Deployment") (.Values.podDisruptionBudget).enabled }}
+{{- if .Capabilities.APIVersions.Has "policy/v1/PodDisruptionBudget" }}
+apiVersion: policy/v1
+{{- else }}
+apiVersion: policy/v1beta1
+{{- end }}
+kind: PodDisruptionBudget
+metadata:
+  name: {{ template "descheduler.fullname" . }}
+  namespace: {{ include "descheduler.namespace" . }}
+  labels:
+    {{- include "descheduler.labels" . | nindent 4 }}
+  {{- with .Values.podDisruptionBudget.annotations }}
+  annotations:
+    {{- toYaml . | nindent 4 }}
+  {{- end }}
+spec:
+  {{- if .Values.podDisruptionBudget.minAvailable }}
+  minAvailable: {{ .Values.podDisruptionBudget.minAvailable }}
+  {{- end }}
+  {{- if .Values.podDisruptionBudget.maxUnavailable }}
+  maxUnavailable: {{ .Values.podDisruptionBudget.maxUnavailable }}
+  {{- end }}
+  {{- with .Values.podDisruptionBudget.unhealthyPodEvictionPolicy }}
+  unhealthyPodEvictionPolicy: {{ . }}
+  {{- end }}
+  selector:
+    matchLabels:
+      {{- include "descheduler.selectorLabels" . | nindent 6 }}
+{{- end }}

charts/descheduler/tests/poddisruptionbudget_test.yaml

@@ -0,0 +1,75 @@
+suite: Test Descheduler PodDisruptionBudget
+
+templates:
+  - "*.yaml"
+
+release:
+  name: descheduler
+
+tests:
+  - it: is not created for the default CronJob kind even when enabled
+    template: templates/poddisruptionbudget.yaml
+    set:
+      podDisruptionBudget:
+        enabled: true
+    asserts:
+      - hasDocuments:
+          count: 0
+
+  - it: is not created for Deployment kind unless enabled
+    template: templates/poddisruptionbudget.yaml
+    set:
+      kind: Deployment
+    asserts:
+      - hasDocuments:
+          count: 0
+
+  - it: creates a PodDisruptionBudget for Deployment kind when enabled
+    template: templates/poddisruptionbudget.yaml
+    set:
+      kind: Deployment
+      podDisruptionBudget:
+        enabled: true
+    asserts:
+      - isKind:
+          of: PodDisruptionBudget
+      - equal:
+          path: spec.minAvailable
+          value: 1
+      - notExists:
+          path: spec.maxUnavailable
+      - equal:
+          path: spec.selector.matchLabels["app.kubernetes.io/name"]
+          value: descheduler
+
+  - it: supports maxUnavailable instead of minAvailable
+    template: templates/poddisruptionbudget.yaml
+    set:
+      kind: Deployment
+      podDisruptionBudget:
+        enabled: true
+        minAvailable: ""
+        maxUnavailable: 1
+    asserts:
+      - equal:
+          path: spec.maxUnavailable
+          value: 1
+      - notExists:
+          path: spec.minAvailable
+
+  - it: supports unhealthyPodEvictionPolicy and annotations
+    template: templates/poddisruptionbudget.yaml
+    set:
+      kind: Deployment
+      podDisruptionBudget:
+        enabled: true
+        unhealthyPodEvictionPolicy: IfHealthyBudget
+        annotations:
+          example.com/team: platform
+    asserts:
+      - equal:
+          path: spec.unhealthyPodEvictionPolicy
+          value: IfHealthyBudget
+      - equal:
+          path: metadata.annotations["example.com/team"]
+          value: platform

charts/descheduler/values.yaml

@@ -80,6 +80,20 @@ leaderElection: {}
 #  resourceName: "descheduler"
 #  resourceNamespace: "kube-system"
 
+# Pod Disruption Budget for the descheduler Deployment. Optional.
+# Only rendered when kind is "Deployment". The descheduler runs a single replica
+# by default, so this is disabled by default. Enable it for highly available
+# setups (replicas > 1 with leaderElection enabled) to keep a descheduler pod
+# available during voluntary node disruptions.
+podDisruptionBudget:
+  enabled: false
+  # minAvailable and maxUnavailable are mutually exclusive; set only one.
+  minAvailable: 1
+  maxUnavailable: ""
+  # See https://kubernetes.io/docs/tasks/run-application/configure-pdb/
+  # unhealthyPodEvictionPolicy: IfHealthyBudget
+  annotations: {}
+
 command:
 - "/bin/descheduler"