K8s复习笔记3-DaemonSet

2. DaemonSet

DaemonSet 确保全部（或者某些）节点上运行一个 Pod 的副本。 当有节点加入集群时， 也会为他们新增一个 Pod 。 当有节点从集群移除时，这些 Pod 也会被回收。删除 DaemonSet 将会删除它创建的所有 Pod。
DaemonSet 的一些典型用法：

• 在每个节点上运行集群守护进程
• 在每个节点上运行日志收集守护进程
• 在每个节点上运行监控守护进程

一种简单的用法是为每种类型的守护进程在所有的节点上都启动一个 DaemonSet。 一个稍微复杂的用法是为同一种守护进程部署多个 DaemonSet；每个具有不同的标志， 并且对不同硬件类型具有不同的内存、CPU 要求。

apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: fluentd-elasticsearch
  namespace: kube-system
  labels:
    k8s-app: fluentd-logging
spec:
  selector:
    matchLabels:
      name: fluentd-elasticsearch
  template:
    metadata:
      labels:
        name: fluentd-elasticsearch
    spec:
      tolerations:
      # 这些容忍度设置是为了让该守护进程集在控制平面节点上运行
      # 如果你不希望自己的控制平面节点运行 Pod，可以删除它们
      - key: node-role.kubernetes.io/control-plane
        operator: Exists
        effect: NoSchedule
      - key: node-role.kubernetes.io/master
        operator: Exists
        effect: NoSchedule
      containers:
      - name: fluentd-elasticsearch
        image: quay.io/fluentd_elasticsearch/fluentd:v2.5.2
        resources:
          limits:
            memory: 200Mi
          requests:
            cpu: 100m
            memory: 200Mi
        volumeMounts:
        - name: varlog
          mountPath: /var/log
        - name: varlibdockercontainers
          mountPath: /var/lib/docker/containers
          readOnly: true
      terminationGracePeriodSeconds: 30
      volumes:
      - name: varlog
        hostPath:
          path: /var/log
      - name: varlibdockercontainers
        hostPath:
          path: /var/lib/docker/containers

在每个节点都启动了fluentd-elasticsearch的pod

 root@k8s-master-01:~/yml# kubectl get pods -o wide -n kube-system
NAME                                       READY   STATUS    RESTARTS   AGE    IP                NODE             NOMINATED NODE   READINESS GATES
calico-kube-controllers-76586bcfb6-2pmfx   1/1     Running   1          100d   192.168.31.111    192.168.31.111   <none>           <none>
calico-node-48nd2                          1/1     Running   0          52d    192.168.31.102    192.168.31.102   <none>           <none>
calico-node-6csj7                          1/1     Running   0          52d    192.168.31.103    192.168.31.103   <none>           <none>
calico-node-brphr                          1/1     Running   1          100d   192.168.31.112    192.168.31.112   <none>           <none>
calico-node-jd8xr                          1/1     Running   0          52d    192.168.31.101    192.168.31.101   <none>           <none>
calico-node-pl8sz                          1/1     Running   0          3d7h   192.168.31.113    192.168.31.113   <none>           <none>
calico-node-xzfgw                          1/1     Running   1          100d   192.168.31.111    192.168.31.111   <none>           <none>
coredns-55556fc4d7-5qnzw                   1/1     Running   0          3d7h   172.100.109.70    192.168.31.111   <none>           <none>
fluentd-elasticsearch-75dsf                1/1     Running   0          37s    172.100.140.76    192.168.31.112   <none>           <none>
fluentd-elasticsearch-g298m                1/1     Running   0          37s    172.100.95.1      192.168.31.102   <none>           <none>
fluentd-elasticsearch-ndttm                1/1     Running   0          37s    172.100.151.129   192.168.31.101   <none>           <none>
fluentd-elasticsearch-nl67m                1/1     Running   0          37s    172.100.109.72    192.168.31.111   <none>           <none>
fluentd-elasticsearch-pztpt                1/1     Running   0          37s    172.100.76.141    192.168.31.113   <none>           <none>
fluentd-elasticsearch-wgvvg                1/1     Running   0          37s    172.100.183.129   192.168.31.103   <none>           <none>
metrics-server-994ccf56d-wqhq6             1/1     Running   0          3d7h   172.100.140.71    192.168.31.112   <none>           <none>