k8s Daemonset功能

1. k8s-Daemonset功能

• DaemonSet功能：

  • 在每一个Node上运行一个Pod
  • 新加入的Node也同样会自动运行一个Pod

• 应用场景：网络插件（kube-proxy、calico）、其他Agent

• 示图：
  

• 示例代码：

  [root@k8s-master deployment]# vim daemonset.yaml
  [root@k8s-master deployment]# cat daemonset.yaml
  apiVersion: apps/v1
  kind: DaemonSet
  metadata:
    name: filebeat
    namespace: kube-system
  spec:
    selector:
      matchLabels:
        name: filebeat
    template:
      metadata:
        labels:
          name: filebeat
      spec:
        containers:
        - name: log
          image: elastic/filebeat:7.3.2
  
  

2. 案例

• 编写配置

  [root@k8s-master deployment]# vim daemonset.yaml
  [root@k8s-master deployment]# cat daemonset.yaml
  apiVersion: apps/v1
  kind: DaemonSet
  metadata:
    name: filebeat
    namespace: kube-system
  spec:
    selector:
      matchLabels:
        name: filebeat
    template:
      metadata:
        labels:
          name: filebeat
      spec:
        containers:
        - name: log
          image: elastic/filebeat:7.3.2
  

• 执行案例

  [root@k8s-master deployment]# kubectl apply -f daemonset.yaml 
  daemonset.apps/filebeat created
  

• 查询服务

  [root@k8s-master deployment]# kubectl get pods -n kube-system 
  NAME                                       READY   STATUS    RESTARTS   AGE
  calico-kube-controllers-5dc87d545c-nscfb   1/1     Running   3          6d20h
  calico-node-j6rhw                          1/1     Running   3          6d20h
  calico-node-n7d6s                          1/1     Running   3          6d20h
  calico-node-x86s2                          1/1     Running   3          6d20h
  coredns-6d56c8448f-hkgnk                   1/1     Running   4          6d23h
  coredns-6d56c8448f-jfbjs                   1/1     Running   3          6d23h
  etcd-k8s-master                            1/1     Running   4          6d23h
  filebeat-7cz4r                             1/1     Running   0          3m25s
  filebeat-tdsm9                             1/1     Running   0          3m25s
  kube-apiserver-k8s-master                  1/1     Running   9          6d23h
  kube-controller-manager-k8s-master         1/1     Running   9          6d23h
  kube-proxy-fhgbd                           1/1     Running   3          6d22h
  kube-proxy-l7q4r                           1/1     Running   3          6d23h
  kube-proxy-qwpjp                           1/1     Running   3          6d22h
  kube-scheduler-k8s-master                  1/1     Running   10         6d23h