Added scheduling.minAvailable

Author: bastianeicher

charts/generic-service/README.md

@@ -69,7 +69,7 @@ app:
 | `rollout.flagger`                               | `false`                     | Use Flagger to control rollouts (`rollout.controller` must be `Deployment` or `StatefulSet`)             |
 | `rollout.analysis`                              | req. for Canary or Flagger  | Flagger or Argo Rollouts analysis for automatic `Canary` or `BlueGreen` promotion                        |
 | `rollout.revisionHistoryLimit`                  | `null`                      | Number of old ReplicaSets to retain (`rollout.controller` must be `Deployment` or `ArgoRollout`)         |
-| `replicas`                                      | `1`                         | The number of instances of the service to run (set at least `2` for Pod Disruption Budget)               |
+| `replicas`                                      | `1`                         | The number of instances of the service to run                                                            |
 | `autoscaling.enabled`                           | `false`                     | Enables automatic starting of additional instances                                                       |
 | `autoscaling.maxReplicas`                       | `3`                         | The maximum number of instances to run (must be larger than `replicas`)                                  |
 | `autoscaling.metric.type`                       | `Resource`                  | The type of metric to use for scaling (`Resource`, `Pods`, `Object` or `External`)                       |
@@ -86,6 +86,7 @@ app:
 | `scheduling.podAffinity`                        | `{}`                        | Labels to select other pods this service should share nodes with if possible                             |
 | `scheduling.podAntiAffinity`                    | `{}`                        | Labels to select other pods this service must not share nodes with                                       |
 | `scheduling.replicaSpread`                      | `BestEffort`                | How to spread replicas across nodes (`BestEffort`, `Strict`, `None`)                                     |
+| `scheduling.minAvailable`                       | `1`                         | Minimum number of instances to keep running during cluster maintenance (only if smaller than `replicas`) |
 | `persistence.enabled`                           | `false`                     | Enables persistent storage for the service                                                               |
 | `persistence.storageClass`                      |                             | The type of disk to use for storage instead of the cluster default                                       |
 | `persistence.accessModes`                       | `[ReadWriteOnce]`           | The support access modes the volume can be mounted with                                                  |

charts/generic-service/ci/scheduling-values.yaml

@@ -4,6 +4,8 @@ image:
   repository: jwilder/whoami
   tag: latest
 
+replicas: 3
+
 scheduling:
   priority: system-cluster-critical
   nodePreferences:
@@ -16,3 +18,4 @@ scheduling:
   podAntiAffinity:
     otherKey: otherValue
   replicaSpread: Strict
+  minAvailable: 2

charts/generic-service/templates/pdb.yaml

@@ -1,4 +1,4 @@
-{{- if and .Values.ingress.enabled (gt .Values.replicas 1.0) }}
+{{- if and (gt .Values.scheduling.minAvailable 0.0) (lt .Values.scheduling.minAvailable .Values.replicas) }}
 
 apiVersion: policy/v1
 kind: PodDisruptionBudget
@@ -7,7 +7,7 @@ metadata:
   labels: {{- include "generic-service.top-level-labels" . | nindent 4 }}
 
 spec:
-  minAvailable: 1
+  minAvailable: {{ .Values.scheduling.minAvailable }}
 
   selector:
     matchLabels: {{- include "generic-service.selector-labels" . | nindent 6 }}

charts/generic-service/values.schema.json

@@ -443,7 +443,7 @@
     "replicas": {
       "type": "integer",
       "default": 1,
-      "description": "The number of instances of the service to run (set at least 2 for Pod Disruption Budget)"
+      "description": "The number of instances of the service to run"
     },
     "autoscaling": {
       "type": "object",
@@ -585,6 +585,11 @@
           ],
           "default": "BestEffort",
           "description": "How to spread replicas across nodes"
+        },
+        "minAvailable": {
+          "type": "integer",
+          "default": 1,
+          "description": "Minimum number of instances to keep running during cluster maintenance (only applied if this value is smaller than replicas)"
         }
       },
       "additionalProperties": false

charts/generic-service/values.yaml

@@ -90,6 +90,7 @@ scheduling:
   podAffinity: {}
   podAntiAffinity: {}
   replicaSpread: BestEffort
+  minAvailable: 1
 
 persistence:
   enabled: false