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K8S中DaemonSet

时间:2019-12-23 20:51:59      阅读:123      评论:0      收藏:0      [点我收藏+]

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DaemonSet

DaemonSet 确保全部(或者一些)Node 上运行一个 Pod 的副本。当有 Node 加入集群时,也会为他们新增一
个 Pod 。当有 Node 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
使用 DaemonSet 的一些典型用法:

  • 运行集群存储 daemon,例如在每个 Node 上运行 glusterd 、 ceph
  • 在每个 Node 上运行日志收集 daemon,例如 fluentd 、 logstash
  • 在每个 Node 上运行监控 daemon,例如 Prometheus Node Exporter、 collectd 、Datadog 代理、New Relic 代理,或 Ganglia gmond
[root@k8s-master mnt]# cat daemonset.yaml
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: deamonset-example
  labels:
    app: daemonset
spec:
  selector:
    matchLabels:
      name: deamonset-example
  template:
    metadata:
      labels:
        name: deamonset-example
    spec:
      containers:
      - name: daemonset-example
        image: wangyanglinux/myapp:v3
[root@k8s-master mnt]#

 

[root@k8s-master mnt]# vim daemonset.yaml
[root@k8s-master mnt]# kubectl create -f daemonset.yaml
daemonset.apps/deamonset-example created
[root@k8s-master mnt]# kubectl get pod -o wide
NAME                      READY   STATUS    RESTARTS   AGE   IP            NODE         NOMINATED NODE   READINESS GATES
deamonset-example-tpdf8   1/1     Running   0          8s    10.244.2.21   k8s-node01   <none>           <none>
deamonset-example-xxt2z   1/1     Running   0          8s    10.244.1.23   k8s-node02   <none>           <none>
[root@k8s-master mnt]# curl 10.244.2.21
Hello MyApp | Version: v3 | <a href="hostname.html">Pod Name</a>
[root@k8s-master mnt]# kubectl delete deamonset-example-tpdf8
error: resource(s) were provided, but no name, label selector, or --all flag specified
[root@k8s-master mnt]# kubectl delete pod deamonset-example-tpdf8
pod "deamonset-example-tpdf8" deleted
[root@k8s-master mnt]# kubectl get pod -o wide
NAME                      READY   STATUS    RESTARTS   AGE    IP            NODE         NOMINATED NODE   READINESS GATES
deamonset-example-vdzjp   1/1     Running   0          3s     10.244.2.22   k8s-node01   <none>           <none>
deamonset-example-xxt2z   1/1     Running   0          107s   10.244.1.23   k8s-node02   <none>           <none>

删除以后,会重新创建一个。

 指定Node节点

DaemonSet会忽略Node的unschedulable状态,有两种方式来指定Pod只运行在指定的Node节点上:

  • nodeSelector:只调度到匹配指定label的Node上
  • nodeAffinity:功能更丰富的Node选择器,比如支持集合操作
  • podAffinity:调度到满足条件的Pod所在的Node上

nodeSelector示例

首先给Node打上标签

kubectl label nodes node-01 disktype=ssd

 

然后在daemonset中指定nodeSelector为disktype=ssd:

spec:
  nodeSelector:
    disktype: ssd

 

nodeAffinity示例

nodeAffinity目前支持两种:requiredDuringSchedulingIgnoredDuringExecution和preferredDuringSchedulingIgnoredDuringExecution,分别代表必须满足条件和优选条件。比如下面的例子代表调度到包含标签kubernetes.io/e2e-az-name并且值为e2e-az1或e2e-az2的Node上,并且优选还带有标签another-node-label-key=another-node-label-value的Node。

apiVersion: v1
kind: Pod
metadata:
  name: with-node-affinity
spec:
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
        nodeSelectorTerms:
        - matchExpressions:
          - key: kubernetes.io/e2e-az-name
            operator: In
            values:
            - e2e-az1
            - e2e-az2
      preferredDuringSchedulingIgnoredDuringExecution:
      - weight: 1
        preference:
          matchExpressions:
          - key: another-node-label-key
            operator: In
            values:
            - another-node-label-value
  containers:
  - name: with-node-affinity
    image: gcr.io/google_containers/pause:2.0

 

podAffinity示例

podAffinity基于Pod的标签来选择Node,仅调度到满足条件Pod所在的Node上,支持podAffinity和podAntiAffinity。这个功能比较绕,以下面的例子为例:

  • 如果一个“Node所在Zone中包含至少一个带有security=S1标签且运行中的Pod”,那么可以调度到该Node
  • 不调度到“包含至少一个带有security=S2标签且运行中Pod”的Node上
apiVersion: v1
kind: Pod
metadata:
  name: with-pod-affinity
spec:
  affinity:
    podAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
      - labelSelector:
          matchExpressions:
          - key: security
            operator: In
            values:
            - S1
        topologyKey: failure-domain.beta.kubernetes.io/zone
    podAntiAffinity:
      preferredDuringSchedulingIgnoredDuringExecution:
      - weight: 100
        podAffinityTerm:
          labelSelector:
            matchExpressions:
            - key: security
              operator: In
              values:
              - S2
          topologyKey: kubernetes.io/hostname
  containers:
  - name: with-pod-affinity
    image: gcr.io/google_containers/pause:2.0

静态Pod

除了DaemonSet,还可以使用静态Pod来在每台机器上运行指定的Pod,这需要kubelet在启动的时候指定manifest目录:

kubelet --pod-manifest-path=/etc/kubernetes/manifests

然后将所需要的Pod定义文件放到指定的manifest目录中。

注意:静态Pod不能通过API Server来删除,但可以通过删除manifest文件来自动删除对应的Pod。

K8S中DaemonSet

标签:yam   VID   操作   代理   tor   val   gluster   dea   lin   

原文地址:https://www.cnblogs.com/dalianpai/p/12088118.html

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