Affinity not applied

Kubernetes
1

Hi,

We got fed up with Redis not behaving well and constantly crashing, even though it was expected to be highly available. So, we moved to Dragonfly, and we’ve been quite happy since then.

However, we noticed an odd behavior, and perhaps it’s something obvious. When setting up podAntiAffinity it’s not actually applied to the StatefulSet (STS) or the pods. I don’t think it can be, but does the operator perform any magic to enforce the affinity settings defined in the Dragonfly resource?

Below is the Dragonfly resource. The affinity section is not being propagated to the StatefulSet created by the operator,

apiVersion: dragonflydb.io/v1alpha1
kind: Dragonfly
metadata:
  labels:
    app.kubernetes.io/managed-by: dragonfly-operator
    app.kubernetes.io/version: 0.0.1
    contact/alerts.pagerduty: Kubernetes_B.Hours
    contact/alerts.slack: engops-notifications
    contact/help.slack: engops-help
    contact/jira: ENGOPS
    contact/owner: EngOps
    helm.sh/chart: levelblue-dragonfly-0.0.4
  name: apm-redis
  namespace: apm
spec:
  affinity:
    podAntiAffinity:
      preferredDuringSchedulingIgnoredDuringExecution:
      - podAffinityTerm:
          labelSelector:
            matchLabels:
              app: apm-redis
          topologyKey: topology.kubernetes.io/zone
        weight: 100
      - podAffinityTerm:
          labelSelector:
            matchLabels:
              app: apm-redis
          topologyKey: kubernetes.io/hostname
        weight: 100
  args:
  - --cluster_mode=emulated
  image: nexus.aveng.me:5000/levelblue-dragonfly:v1.34.2
  imagePullPolicy: Always
  labels:
    app: apm-redis
    app.kubernetes.io/managed-by: dragonfly-operator
    app.kubernetes.io/version: 0.0.1
    contact/alerts.pagerduty: Kubernetes_B.Hours
    contact/alerts.slack: engops-notifications
    contact/help.slack: engops-help
    contact/jira: ENGOPS
    contact/owner: EngOps
    helm.sh/chart: levelblue-dragonfly-0.0.4
  replicas: 3
  resources:
    limits:
      cpu: 600m
      memory: 750Mi
    requests:
      cpu: 500m
      memory: 500Mi
2

It works now. Perhaps we had something not updated.

3

Thanks for the update!

We don’t get a lot of issue reports regarding this, to be honest.

If you encounter something in the future regarding the operator, consider opening a GitHub issue directly as well in the Dragonfly K8s Operator repo.