Agent: add pod disruption budged and topology spread constraints (#9)

* agent: add pdb and topology spread

* agent: bump chart version to 0.4.0

Author: benben

charts/agent/Chart.yaml

@@ -15,7 +15,7 @@ type: application
 # This is the chart version. This version number should be incremented each time you make changes
 # to the chart and its templates, including the app version.
 # Versions are expected to follow Semantic Versioning (https://semver.org/)
-version: 0.3.2
+version: 0.4.0
 
 # This is the version number of the application being deployed. This version number should be
 # incremented each time you make changes to the application. Versions are not expected to

charts/agent/templates/deployment.yaml

@@ -98,3 +98,7 @@ spec:
       tolerations:
         {{- toYaml . | nindent 8 }}
       {{- end }}
+      {{- with .Values.topologySpreadConstraints }}
+      topologySpreadConstraints:
+        {{- toYaml . | nindent 8 }}
+      {{- end }}

charts/agent/templates/poddisruptionbudget.yaml

@@ -0,0 +1,19 @@
+{{- if .Values.podDisruptionBudget.enabled -}}
+apiVersion: policy/v1
+kind: PodDisruptionBudget
+metadata:
+  name: {{ include "agent.fullname" . }}
+  namespace: {{ .Release.Namespace }}
+  labels:
+    {{- include "agent.labels" . | nindent 4 }}
+spec:
+  {{- if .Values.podDisruptionBudget.minAvailable }}
+  minAvailable: {{ .Values.podDisruptionBudget.minAvailable }}
+  {{- end }}
+  {{- if .Values.podDisruptionBudget.maxUnavailable }}
+  maxUnavailable: {{ .Values.podDisruptionBudget.maxUnavailable }}
+  {{- end }}
+  selector:
+    matchLabels:
+      {{- include "agent.selectorLabels" . | nindent 6 }}
+{{- end }}

charts/agent/values.yaml

@@ -110,4 +110,41 @@ nodeSelector: {}
 
 tolerations: []
 
+# https://kubernetes.io/docs/concepts/scheduling-eviction/assign-pod-node/#affinity-and-anti-affinity
 affinity: {}
+# podAntiAffinity:
+#   requiredDuringSchedulingIgnoredDuringExecution:
+#     - labelSelector:
+#         matchExpressions:
+#           - key: app.kubernetes.io/name
+#             operator: In
+#             values:
+#               - agent
+#           - key: app.kubernetes.io/instance
+#             operator: In
+#             values:
+#               - RELEASE-NAME
+#       topologyKey: kubernetes.io/hostname
+
+# https://kubernetes.io/docs/tasks/run-application/configure-pdb/
+podDisruptionBudget:
+  enabled: false
+  # minAvailable: 1
+  # maxUnavailable: 1
+  # Only one of minAvailable or maxUnavailable can be set
+
+# https://kubernetes.io/docs/concepts/scheduling-eviction/topology-spread-constraints/
+topologySpreadConstraints: []
+# Example configurations:
+# - maxSkew: 1
+#   topologyKey: topology.kubernetes.io/zone
+#   whenUnsatisfiable: DoNotSchedule
+#   labelSelector:
+#     matchLabels:
+#       app.kubernetes.io/name: agent
+# - maxSkew: 1
+#   topologyKey: kubernetes.io/hostname
+#   whenUnsatisfiable: ScheduleAnyway
+#   labelSelector:
+#     matchLabels:
+#       app.kubernetes.io/name: agent