通常Kubernetes Master节点上会有污点Taints，如果希望DaemonSet运行在Kubernetes所有节点上则需要在Pod Spec层级添加对应tolerations。

1. 查看Master节点Tolerations

可以通过kuberctl describe nodes 查看指定Master Taints

[root@k8s~]# kubectl describe nodes kubernetes-master01
Name:               kubernetes-master01
Roles:              controlplane,etcd
Labels:             beta.kubernetes.io/arch=amd64
                    beta.kubernetes.io/os=linux
                    kubernetes.io/arch=amd64
                    kubernetes.io/hostname=kubernetes-master01
                    kubernetes.io/os=linux
                    node-role.kubernetes.io/controlplane=true
                    node-role.kubernetes.io/etcd=true
Annotations:        flannel.alpha.coreos.com/backend-data: {"VtepMAC":"ca:89:74:c4:d1:5d"}
                    flannel.alpha.coreos.com/backend-type: vxlan
                    flannel.alpha.coreos.com/kube-subnet-manager: true
                    flannel.alpha.coreos.com/public-ip: 10.10.10.1
                    node.alpha.kubernetes.io/ttl: 0
                    projectcalico.org/IPv4IPIPTunnelAddr: 10.42.1.1
                    rke.cattle.io/external-ip: 10.10.10.1
                    rke.cattle.io/internal-ip: 10.10.10.1
                    volumes.kubernetes.io/controller-managed-attach-detach: true
CreationTimestamp:  Sat, 27 Jun 2020 19:06:44 +0800
Taints:             node-role.kubernetes.io/etcd=true:NoExecute
                    node-role.kubernetes.io/controlplane=true:NoSchedule
Unschedulable:      false
Lease:
  HolderIdentity:  kubernetes-master01
  AcquireTime:     <unset>
  RenewTime:       Sun, 19 Jul 2020 17:30:00 +0800

2. 在DaemonSet YAML中配置Tolerations

  在pod spec层级下添加tolerations对应Master节点上的Taints。

---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: daemonset-test
  namespace: demo
spec:
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      tolerations:
        - key: node-role.kubernetes.io/controlplane
          operator: Exists
          effect: NoSchedule
        - key: node-role.kubernetes.io/etcd
          operator: Exists
          effect: NoExecute
      containers:
        - name: nginx
          image: nginx:latest
          imagePullPolicy: IfNotPresent

3. 查看效果

可以看到DaemonSet在Kubernetes所有节点上都运行了一个Pod。

[root@k8s ~]# kubectl get pod -n demo -o wide
NAME                   READY   STATUS    RESTARTS   AGE   IP            NODE                  NOMINATED NODE   READINESS GATES
daemonset-test-9tq2n   1/1     Running   0          26m   10.42.2.2     kubernetes-master03   <none>           <none>
daemonset-test-pxqdf   1/1     Running   0          26m   10.42.0.2     kubernetes-master02   <none>           <none>
daemonset-test-gxc8j   1/1     Running   0          26m   10.42.1.3     kubernetes-master01   <none>           <none>
daemonset-test-2vd94   1/1     Running   0          26m   10.42.5.93    kubernetes-node01     <none>           <none>
daemonset-test-wnsdc   1/1     Running   0          26m   10.42.4.145   kubernetes-node03     <none>           <none>
daemonset-test-zz9wp   1/1     Running   0          26m   10.42.3.22    kubernetes-node02     <none>           <none>