Advanced DaemonSet in OpenKruise: Granular Rolling Updates for Large Clusters

Overview

OpenKruise extends the native Kubernetes DaemonSet with an Advanced DaemonSet controller that provides production‑grade rollout capabilities for large, heterogeneous clusters.

Key API Additions

type RollingUpdateType string
const (
    StandardRollingUpdateType RollingUpdateType = "Standard"
    SurgingRollingUpdateType  RollingUpdateType = "Surging"
)

type RollingUpdateDaemonSet struct {
    Type           RollingUpdateType        `json:"rollingUpdateType,omitempty"`
    MaxUnavailable *intstr.IntOrString    `json:"maxUnavailable,omitempty"`
    Selector       *metav1.LabelSelector   `json:"selector,omitempty"`
    Partition      *int32                  `json:"partition,omitempty"`
    Paused         *bool                   `json:"paused,omitempty"`
    MaxSurge       *intstr.IntOrString    `json:"maxSurge,omitempty"`
}

type DaemonSetSpec struct {
    // ... other fields ...
    BurstReplicas *intstr.IntOrString `json:"burstReplicas,omitempty"`
}

Rollout Strategies

Node‑level Canary (selector) Use a label selector to target a subset of nodes. Only nodes matching selector.matchLabels receive the new Pod version.

apiVersion: apps.kruise.io/v1alpha1
kind: DaemonSet
spec:
  updateStrategy:
    type: RollingUpdate
    rollingUpdate:
      selector:
        matchLabels:
          nodeType: canary

Quantity‑based Partition Define partition to keep a fixed number of Pods on the old version. The controller updates status.DesiredNumberScheduled - partition Pods at a time.

apiVersion: apps.kruise.io/v1alpha1
kind: DaemonSet
spec:
  updateStrategy:
    type: RollingUpdate
    rollingUpdate:
      partition: 100

For a DaemonSet on 120 nodes, partition: 100 upgrades only 20 Pods initially.

Multi‑dimensional Gray‑scale Combine selector , partition , and optionally maxUnavailable . The controller first filters nodes by the selector, then applies the partition count within that subset, and finally caps concurrent updates with maxUnavailable .

apiVersion: apps.kruise.io/v1alpha1
kind: DaemonSet
spec:
  updateStrategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 5
      partition: 100
      selector:
        matchLabels:
          nodeType: canary

Hot Upgrade (Surging) Set type: Surging to create new Pods before deleting old ones. maxSurge (absolute number or percentage) limits the number of extra Pods that can run concurrently, enabling zero‑downtime upgrades.

apiVersion: apps.kruise.io/v1alpha1
kind: DaemonSet
spec:
  updateStrategy:
    rollingUpdate:
      type: Surging
      maxSurge: 30%

Publish Pause Set paused: true to stop the controller from processing further updates.

apiVersion: apps.kruise.io/v1alpha1
kind: DaemonSet
spec:
  updateStrategy:
    rollingUpdate:
      paused: true

Usage Example

A typical Advanced DaemonSet manifest combining selector, partition, and maxUnavailable:

apiVersion: apps.kruise.io/v1alpha1
kind: DaemonSet
metadata:
  name: my-daemon
spec:
  selector:
    matchLabels:
      app: my-daemon
  template:
    metadata:
      labels:
        app: my-daemon
    spec:
      containers:
      - name: daemon
        image: my-image:v2
  updateStrategy:
    type: RollingUpdate
    rollingUpdate:
      selector:
        matchLabels:
          nodeType: canary
      partition: 80
      maxUnavailable: 10

Repository

Source code and releases are hosted at https://github.com/openkruise/kruise.