DaemonSet 应用

DaemonSet 资源

• DaemonSet 用于在集群的每个节点上运行特定的 Pod，确保每个节点都有一个 Pod 的副本在运行。这对于在集群中的每个节点上运行后台任务、监控代理、日志收集器等常驻性任务非常有用。

• aemonSet 不会根据副本数来调度 Pod。相反，它会根据节点的数量自动创建或删除 Pod，以确保每个节点上都有一个 Pod 的副本在运行。

1. 编写YAML文件
   编写 daemonset-nginx.yml

   apiVersion: apps/v1
   kind: DaemonSet
   metadata:
     name: daemonset-nginx         
   spec:
     selector:
       matchLabels:
         name: nginx-ds
     template:
       metadata:
         labels:
           name: nginx-ds
       spec:
         tolerations:                      # tolerations代表容忍
         - key: node-role.kubernetes.io/master  # 能容忍的污点key
           effect: NoSchedule   # kubectl explain pod.spec.tolerations查看(能容忍的污点effect)
         containers:
         - name: nginx
           image: nginx:1.15-alpine
           imagePullPolicy: IfNotPresent
           resources:    # resources资源限制是为了防止master节点的资源被占太多(根据实际情况配置)
             limits:
               memory: 100Mi
             requests:
               memory: 100Mi
   

2. apply 应用 YAML 文件

   [root@k8smaster001 ~]# kubectl apply -f daemonset-nginx.yml 
   daemonset.apps/daemonset-nginx created
   

3. 验证

   [root@k8smaster001 ~]# kubectl get daemonset
   NAME              DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR   AGE
   daemonset-nginx   2         2         1       2            1           <none>          23s
   

[root@k8smaster001 ~]# kubectl get pods -o wide
NAME                    READY   STATUS    RESTARTS   AGE   IP              NODE           NOMINATED NODE   READINESS GATES
daemonset-nginx-jl7lj   1/1     Running   0          90s   10.244.35.59    k8sworker002   <none>           <none>
daemonset-nginx-n2mpr   1/1     Running   0          90s   10.244.87.228   k8sworker001   <none>           <none>

k8s集群中每个 worker 节点都会运行一个pod