feat(chart): configure best effort topology spread constraints for k8…

…sensor deployment
instana · Feb 6, 2024 · 3311df3 · 3311df3
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diff --git a/instana-agent/README.md b/instana-agent/README.md
@@ -141,6 +141,7 @@ The following table lists the configurable parameters of the Instana chart and t
 | `zones`                                             | Multi-zone daemonset configuration.                                                                                                                                                                                                                                                                                    | `nil` see [below](#multiple-zones) for details                                                                                          |
 | `k8s_sensor.podDisruptionBudget.enabled`            | Whether to create DisruptionBudget for k8sensor to limit the number of concurrent disruptions                                                                                                                                                                                                                          | `false`                                                                                                                                 |
 | `k8s_sensor.deployment.pod.affinity`                | `k8sensor` deployment affinity format                                                                                                                                                                                                                                                                                  | `podAntiAffinity` defined in `values.yaml`                                                                                              |
+| `k8s_sensor.deployment.pod.topologySpreadConstraints`                | `k8sensor` deployment topology spread constraints format                                                                                                                                                                                                                                                                                  | `topologySpreadConstraints` defined in `values.yaml`                                                                                              |
 
 ### Agent Modes
 

diff --git a/instana-agent/templates/k8s-sensor-deployment.yaml b/instana-agent/templates/k8s-sensor-deployment.yaml
@@ -127,6 +127,8 @@ spec:
       {{- end }}
       affinity:
         {{- toYaml .Values.k8s_sensor.deployment.pod.affinity | nindent 8 }}
+      topologySpreadConstraints:
+        {{- toYaml .Values.k8s_sensor.deployment.pod.topologySpreadConstraints | nindent 8 }}
 {{- end -}}
 {{- end -}}
 {{- end -}}
diff --git a/instana-agent/values.yaml b/instana-agent/values.yaml
@@ -259,6 +259,23 @@ k8s_sensor:
                   operator: In
                   values: [ KUBERNETES ]
               topologyKey: "kubernetes.io/hostname"
+      # k8s_sensor.deployment.pod.topologySpreadConstraints are constraints to influence how pods are distributed accross nodes
+      # https://kubernetes.io/docs/concepts/scheduling-eviction/topology-spread-constraints/
+      topologySpreadConstraints:
+        - labelSelector:
+            matchLabels:
+              app.kubernetes.io/instance: instana-agent
+              app: k8sensor
+          maxSkew: 1
+          topologyKey: topology.kubernetes.io/zone
+          whenUnsatisfiable: ScheduleAnyway
+        - labelSelector:
+            matchLabels:
+              app.kubernetes.io/instance: instana-agent
+              app: k8sensor
+          maxSkew: 1
+          topologyKey: kubernetes.io/hostname
+          whenUnsatisfiable: ScheduleAnyway
   podDisruptionBudget:
     # Specifies whether or not to setup a pod disruption budget for the k8sensor deployment
     enabled: false