Add configurable topologySpreadConstraints for Trino gateway deployment (#336)

Author: raj-manvar

charts/gateway/README.md

@@ -145,6 +145,18 @@ A Helm chart for Trino Gateway
 * `terminationGracePeriodSeconds` - int, default: `30`
 * `nodeSelector` - object, default: `{}`
 * `tolerations` - list, default: `[]`
+* `topologySpreadConstraints` - list, default: `[]`  
+
+  [Deployment Topology Spread Constraints](https://kubernetes.io/docs/concepts/scheduling-eviction/topology-spread-constraints/) configuration. Useful to control how Pods are spread across domains such as regions, zones, nodes etc.
+  Example:
+  ```yaml
+   - maxSkew: 1
+     topologyKey: "kubernetes.io/hostname"
+     whenUnsatisfiable: ScheduleAnyway
+   - maxSkew: 1
+     topologyKey: "topology.kubernetes.io/zone"
+     whenUnsatisfiable: ScheduleAnyway
+  ```
 * `affinity` - object, default: `{}`
 * `commonLabels` - object, default: `{}`  
 

charts/gateway/templates/deployment.yaml

@@ -121,3 +121,7 @@ spec:
       tolerations:
         {{- toYaml . | nindent 8 }}
       {{- end }}
+      {{- with .Values.topologySpreadConstraints }}
+      topologySpreadConstraints:
+        {{- toYaml . | nindent 8 }}
+      {{- end }}

charts/gateway/values.yaml

@@ -192,6 +192,21 @@ nodeSelector: {}
 
 tolerations: []
 
+topologySpreadConstraints: []
+# topologySpreadConstraints -- [Deployment Topology Spread Constraints](https://kubernetes.io/docs/concepts/scheduling-eviction/topology-spread-constraints/) configuration.
+# Useful to control how Pods are spread across domains such as regions, zones, nodes etc.
+# @raw
+# Example:
+# ```yaml
+#  - maxSkew: 1
+#    topologyKey: "kubernetes.io/hostname"
+#    whenUnsatisfiable: ScheduleAnyway
+#  - maxSkew: 1
+#    topologyKey: "topology.kubernetes.io/zone"
+#    whenUnsatisfiable: ScheduleAnyway
+# ```
+
+
 affinity: {}
 
 # -- Labels that get applied to every resource's metadata