[logstash] feat: add podAffinity settings (#1257) (#1275)

Co-authored-by: t.decaux <t.decaux@qwant.com>

Co-authored-by: Thomas Decaux <ebuildy@gmail.com>
Co-authored-by: t.decaux <t.decaux@qwant.com>

logstash/README.md

@@ -133,6 +133,7 @@ useful for the [http input plugin][], for instance.
 | `maxUnavailable`          | The [maxUnavailable][] value for the pod disruption budget. By default this will prevent Kubernetes from having more than 1 unhealthy pod in the node group                                                                          | `1`                                   |
 | `nameOverride`            | Overrides the chart name for resources. If not set the name will default to `.Chart.Name`                                                                                                                                            | `""`                                  |
 | `nodeAffinity`            | Value for the [node affinity settings][]                                                                                                                                                                                             | `{}`                                  |
+| `podAffinity`             | Value for the [pod affinity settings][]                                                                                                                                                                                             | `{}`                                  |
 | `nodeSelector`            | Configurable [nodeSelector][] so that you can target specific nodes for your Logstash cluster                                                                                                                                        | `{}`                                  |
 | `persistence`             | Enables a persistent volume for Logstash data                                                                                                                                                                                        | see [values.yaml][]                   |
 | `podAnnotations`          | Configurable [annotations][] applied to all Logstash pods                                                                                                                                                                            | `{}`                                  |
@@ -220,7 +221,8 @@ about our development and testing process.
 [logstash docker image]: https://www.elastic.co/guide/en/logstash/6.8/docker.html
 [logstash oss docker image]: https://www.docker.elastic.co/r/logstash/logstash-oss
 [maxUnavailable]: https://kubernetes.io/docs/tasks/run-application/configure-pdb/#specifying-a-poddisruptionbudget
-[node affinity settings]: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#node-affinity-beta-feature
+[node affinity settings]: https://kubernetes.io/docs/tasks/configure-pod-container/assign-pods-nodes-using-node-affinity/
+[pod affinity settings]: https://kubernetes.io/docs/concepts/scheduling-eviction/assign-pod-node/#inter-pod-affinity-and-anti-affinity
 [nodeSelector]: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#nodeselector
 [note]: https://www.elastic.co/guide/en/logstash/6.8/docker-config.html#docker-env-config
 [priorityClass]: https://kubernetes.io/docs/concepts/configuration/pod-priority-preemption/#priorityclass

logstash/templates/statefulset.yaml

@@ -80,7 +80,7 @@ spec:
       nodeSelector:
 {{ toYaml . | indent 8 }}
       {{- end }}
-      {{- if or (eq .Values.antiAffinity "hard") (eq .Values.antiAffinity "soft") .Values.nodeAffinity }}
+      {{- if or (eq .Values.antiAffinity "hard") (eq .Values.antiAffinity "soft") .Values.nodeAffinity .Values.podAffinity }}
       {{- if .Values.priorityClassName }}
       priorityClassName: {{ .Values.priorityClassName }}
       {{- end }}
@@ -111,6 +111,10 @@ spec:
       {{- end }}
       {{- with .Values.nodeAffinity }}
         nodeAffinity:
+{{ toYaml . | indent 10 }}
+      {{- end }}
+      {{- with .Values.podAffinity }}
+        podAffinity:
 {{ toYaml . | indent 10 }}
       {{- end }}
       terminationGracePeriodSeconds: {{ .Values.terminationGracePeriod }}
@@ -204,7 +208,7 @@ spec:
           {{- range $path, $config := .Values.logstashPattern }}
           - name: logstashpattern
             mountPath: {{ $logstashPatternDir }}{{ $path }}
-            subPath: {{ $path }} 
+            subPath: {{ $path }}
           {{- end -}}
           {{- end -}}
         {{- if .Values.extraVolumeMounts }}

logstash/tests/logstash_test.py

@@ -557,6 +557,28 @@ def test_adding_a_node_affinity():
     }
 
 
+def test_adding_a_pod_affinity_rule():
+    config = """
+podAffinity:
+  requiredDuringSchedulingIgnoredDuringExecution:
+  - labelSelector:
+      matchExpressions:
+      - key: app
+        operator: In
+        values:
+        - elasticsearch
+    topologyKey: kubernetes.io/hostname
+"""
+
+    r = helm_template(config)
+    assert (
+        r["statefulset"][name]["spec"]["template"]["spec"]["affinity"]["podAffinity"][
+            "requiredDuringSchedulingIgnoredDuringExecution"
+        ][0]["topologyKey"]
+        == "kubernetes.io/hostname"
+    )
+
+
 def test_adding_in_logstash_config():
     config = """
 logstashConfig:

logstash/values.yaml

@@ -160,9 +160,13 @@ antiAffinityTopologyKey: "kubernetes.io/hostname"
 antiAffinity: "hard"
 
 # This is the node affinity settings as defined in
-# https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#node-affinity-beta-feature
+# https://kubernetes.io/docs/concepts/scheduling-eviction/assign-pod-node/#node-affinity
 nodeAffinity: {}
 
+# This is inter-pod affinity settings as defined in
+# https://kubernetes.io/docs/concepts/scheduling-eviction/assign-pod-node/#inter-pod-affinity-and-anti-affinity
+podAffinity: {}
+
 # The default is to deploy all pods serially. By setting this to parallel all pods are started at
 # the same time when bootstrapping the cluster
 podManagementPolicy: "Parallel"