Kubernetes：并行更新所有 pod

Question

Is there any way to perform an update action on all pods simultaneously?

We have a process running in kubernetes as a stateful set where we want to update all the pods at the same time. We cannot seem to find a configuration for that. I am aware of rollingUpdate , which only updates one pod at a time.

This is what we have currently

  updateStrategy:
    rollingUpdate:
      partition: 2
    type: RollingUpdate

I also tried with maxUnavailable , but still did not work. Is there any other hack to get this done?

Answer 1

There is no native alternative for updating all pods simultaneously when using Statefulsets.

The closest thing to it is to use the Parallel Pod Management policy , but it only affects the behavior for scaling operations (including initial setup) and doesn't work for updates.

---

Although, the OpenKruise project has an extended component suite that enables Advanced StatefulSet to update workflow.

Here is a minimal working example that will upgrade all pods at once :

apiVersion: apps.kruise.io/v1beta1
kind: StatefulSet
metadata:
  name: sample
spec:
  replicas: 5
  serviceName: fake-service
  selector:
    matchLabels:
      app: sample
  template:
    metadata:
      labels:
        app: sample
    spec:
      readinessGates:
      - conditionType: InPlaceUpdateReady
      containers:
      - name: main
        image: nginx:alpine
  podManagementPolicy: Parallel
  updateStrategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 100%

Note this will certainly cause downtime , but you can adjust to something like maxUnavailable: 50% to make it more resilient.