Kubernetes 之 DaemonSet 根本原理
DaemonSet 界说
DaemonSet 确保全部（或者某些）节点上运行一个 Pod 的副本。 当有节点参加集群时， 也会为他们新增一个 Pod 。 当有节点从集群移除时，这些 Pod 也会被接纳。删除 DaemonSet 将会删除它创建的全部 Pod。它最经常被使用在收集集群日志的用途上。
DaemonSet 使用
- 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
- # 可能需要设置较高的优先级类以确保 DaemonSet Pod 可以抢占正在运行的 Pod
- # priorityClassName: important
- terminationGracePeriodSeconds: 30
- volumes:
- - name: varlog
- hostPath:
- path: /var/log
- root@k8s-master1:~# kubectl get ds -n kube-system
- NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE
- fluentd-elasticsearch 3 3 3 3 3 <none> 112s
- kube-proxy 3 3 3 3 3 kubernetes.io/os=linux 18d
- root@k8s-master1:~# kubectl get pods -n kube-system -owide -l name=fluentd-elasticsearch
- NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
- fluentd-elasticsearch-6fmkb 1/1 Running 0 3m8s 10.244.194.122 k8s-worker1 <none> <none>
- fluentd-elasticsearch-pd4ps 1/1 Running 0 3m8s 10.244.159.156 k8s-master1 <none> <none>
- fluentd-elasticsearch-tkkvq 1/1 Running 0 3m8s 10.244.126.2 k8s-worker2 <none> <none>
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