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kubernetes运行应用2之DaemonSet详解

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kubernetes运行应用1之Deployment详解

查看daemonset

如下，k8s自身的 DaemonSet kube-flannel-ds和kube-proxy分别负责在每个结点上运行flannel和kube-proxy组件
daemonset在每个节点上最多只能运行一个副本。 

[machangwei@mcwk8s-master ~]$ kubectl get daemonset

No resources found in default namespace.

[machangwei@mcwk8s-master ~]$ kubectl get daemonset  --namespace=kube-system

NAME              DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR            AGE

kube-flannel-ds   3         3         1       3            1           <none>                   5d

kube-proxy        3         3         3       3            3           kubernetes.io/os=linux   5d

[machangwei@mcwk8s-master ~]$ kubectl get pod --namespace=kube-system  -o wide

NAME                                    READY   STATUS             RESTARTS          AGE   IP           NODE            NOMINATED NODE   READINESS GATES

coredns-6d8c4cb4d-cnj2t                 1/1     Running            0                 5d    10.244.0.2   mcwk8s-master   <none>           <none>

coredns-6d8c4cb4d-ngfm4                 1/1     Running            0                 5d    10.244.0.3   mcwk8s-master   <none>           <none>

etcd-mcwk8s-master                      1/1     Running            0                 5d    10.0.0.4     mcwk8s-master   <none>           <none>

kube-apiserver-mcwk8s-master            1/1     Running            1 (13h ago)       5d    10.0.0.4     mcwk8s-master   <none>           <none>

kube-controller-manager-mcwk8s-master   1/1     Running            5 (80m ago)       5d    10.0.0.4     mcwk8s-master   <none>           <none>

kube-flannel-ds-cn4m9                   0/1     CrashLoopBackOff   147 (3m51s ago)   12h   10.0.0.6     mcwk8s-node2    <none>           <none>

kube-flannel-ds-hpgkz                   1/1     Running            0                 5d    10.0.0.4     mcwk8s-master   <none>           <none>

kube-flannel-ds-nnjvj                   0/1     CrashLoopBackOff   185 (3m38s ago)   5d    10.0.0.5     mcwk8s-node1    <none>           <none>

kube-proxy-92g5c                        1/1     Running            0                 12h   10.0.0.6     mcwk8s-node2    <none>           <none>

kube-proxy-kk22j                        1/1     Running            0                 5d    172.16.0.5   mcwk8s-node1    <none>           <none>

kube-proxy-xjjgf                        1/1     Running            0                 5d    10.0.0.4     mcwk8s-master   <none>           <none>

kube-scheduler-mcwk8s-master            1/1     Running            5 (82m ago)       5d    10.0.0.4     mcwk8s-master   <none>           <none>

[machangwei@mcwk8s-master ~]$

学习kube-flannel-ds

截取部分：https://www.cnblogs.com/machangwei-8/p/15759077.html#_label7 

apiVersion: apps/v1

kind: DaemonSet  #语法结构和Deployment几乎往前一样，只是将kind设为DaemonSet

metadata:

  name: kube-flannel-ds

  namespace: kube-system

  labels:

    tier: node

    app: flannel

spec:

  selector:

    matchLabels:

      app: flannel

  template:

    metadata:

      labels:

        tier: node

        app: flannel

    spec:

      hostNetwork: true #指定Pod直接使用的是Node网络，相当于docker run --network=host。

               #考虑到flannel需要为集群提供网络连接，这个要求是合理的

      initContainers:#定义了运行flannel服务的两个容器

      - name: install-cni-plugin

        image: rancher/mirrored-flannelcni-flannel-cni-plugin:v1.0.0

        command:

      containers:   #定义了运行flannel服务的两个容器

      - name: kube-flannel

        image: quay.io/coreos/flannel:v0.15.1

        command:

        - /opt/bin/flanneld

        args:

        - --ip-masq

        - --kube-subnet-mgr

学习kube-proxy,查看daemonset配置 
[machangwei@mcwk8s-master ~]$ kubectl edit daemonset kube-proxy --namespace=kube-system

# Please edit the object below. Lines beginning with a '#' will be ignored,

# and an empty file will abort the edit. If an error occurs while saving this file will be

# reopened with the relevant failures.

#

apiVersion: apps/v1

kind: DaemonSet #指定资源类型

metadata:

  annotations:

    deprecated.daemonset.template.generation: "1"

  creationTimestamp: "2022-01-12T15:15:18Z"

  generation: 1

  labels:

    k8s-app: kube-proxy

  name: kube-proxy

  namespace: kube-system

  resourceVersion: "18274"

  uid: 04cfea8d-94b3-4963-b8d2-b10a7b6a46b0

spec:

  revisionHistoryLimit: 10

  selector:

    matchLabels:

      k8s-app: kube-proxy

  template:

    metadata:

      creationTimestamp: null

      labels:

        k8s-app: kube-proxy

    spec:

      containers:

      - command:

        - /usr/local/bin/kube-proxy

# Please edit the object below. Lines beginning with a '#' will be ignored,

# and an empty file will abort the edit. If an error occurs while saving this file will be

# reopened with the relevant failures.

#

apiVersion: apps/v1

kind: DaemonSet   #指定资源类型

metadata:

  annotations:

    deprecated.daemonset.template.generation: "1"

  creationTimestamp: "2022-01-12T15:15:18Z"

  generation: 1

  labels:

    k8s-app: kube-proxy

  name: kube-proxy

  namespace: kube-system

  resourceVersion: "18274"

  uid: 04cfea8d-94b3-4963-b8d2-b10a7b6a46b0

spec:

  revisionHistoryLimit: 10

  selector:

    matchLabels:

      k8s-app: kube-proxy

  template:

    metadata:

      creationTimestamp: null

      labels:

        k8s-app: kube-proxy

    spec:

      containers:  #定义kube-proxy的容器

      - command:

        - /usr/local/bin/kube-proxy

        - --config=/var/lib/kube-proxy/config.conf

        - --hostname-override=$(NODE_NAME)

        env:

        - name: NODE_NAME

          valueFrom:

            fieldRef:

              apiVersion: v1

              fieldPath: spec.nodeName

        image: registry.aliyuncs.com/google_containers/kube-proxy:v1.23.1

        imagePullPolicy: IfNotPresent

        name: kube-proxy

        resources: {}

        securityContext:

          privileged: true

        terminationMessagePath: /dev/termination-log

        terminationMessagePolicy: File

        volumeMounts:

        - mountPath: /var/lib/kube-proxy

          name: kube-proxy

        - mountPath: /run/xtables.lock

          name: xtables-lock

        - mountPath: /lib/modules

          name: lib-modules

          readOnly: true

      dnsPolicy: ClusterFirst

      hostNetwork: true

      nodeSelector:

        kubernetes.io/os: linux

      priorityClassName: system-node-critical

      restartPolicy: Always

      schedulerName: default-scheduler

      securityContext: {}

      serviceAccount: kube-proxy

      serviceAccountName: kube-proxy

      terminationGracePeriodSeconds: 30

      tolerations:

      - operator: Exists

      volumes:

      - configMap:

          defaultMode: 420

          name: kube-proxy

        name: kube-proxy

      - hostPath:

          path: /run/xtables.lock

          type: FileOrCreate

        name: xtables-lock

      - hostPath:

          path: /lib/modules

          type: ""

        name: lib-modules

  updateStrategy:

    rollingUpdate:

      maxSurge: 0

      maxUnavailable: 1

    type: RollingUpdate

status:  #当前DamonSet的运行状态，这个部分是kubectl edit 特有的。其实kubernetes集群中每个当前运行的资源都

  currentNumberScheduled: 3 #可以通过kubectl edit 查看器配置和运行状态，

  desiredNumberScheduled: 3 #比如： kubectl edit deployment mcwnginx-deployment

  numberAvailable: 3

  numberMisscheduled: 0

  numberReady: 3

  observedGeneration: 1

  updatedNumberScheduled: 3

[machangwei@mcwk8s-master ~]$ kubectl edit daemonset kube-proxy --namespace=kube-system #跟vim一样，q退出，如果修改了那么应该是wq吧

Edit cancelled, no changes made.

运行自己的DaemonSet失败

有时间再看这个失败问题，如果哪位大佬知道，指点下也好 

[machangwei@mcwk8s-master ~]$ vim mcwJiankong.yml

[machangwei@mcwk8s-master ~]$ cat mcw

cat: mcw: No such file or directory

[machangwei@mcwk8s-master ~]$ cat mcw

mcwJiankong.yml  mcwNginx.yml

[machangwei@mcwk8s-master ~]$ cat mcwJiankong.yml

apiVersion: apps/v1

kind: DaemonSet

metadata:

  name: mcw-prometheus-node-daemonset

spec:

  replicas: 3

  selector:

    matchLabels:

     app: mcw_prometheus

  template:

    metadata:

      labels:

        app: mcw_prometheus

    spec:

      hostNetwork: true

      containers:

        - name: mcw-pr-node

          image: prom/node-exporter

          imagePullPolicy: IfNotPresent

          command:

          - /bin/node_exporter

          - --pathprocfs

          - /host/proc

          - --path.sysfs

          - /host/sys

          - --collector.filesystem.ignored-mount-points

          - ^/(sys|proc|dev|host|etc)($|/)

          volumeMounts:

          - name: proc

            mountPath: /host/proc

          - name: sys

            mountPath: /host/sys

          - name: root

            mountPath: /rootfs

      volumes:

      - name: proc

        hostPath:

          path: /proc

      - name: sys

        hostPath:

          path: /sys

      - name: root

        hostPath:

          path: /

[machangwei@mcwk8s-master ~]$ kubectl apply -f mcwJiankong.yml  #daemonset不能指定副本数量，好像每个节点都会运行，这里可能没包括主节点

error: error validating "mcwJiankong.yml": error validating data: ValidationError(DaemonSet.spec): unknown field "replicas" in io.k8s.api.apps.v1.DaemonSetSpec; if you choose to ignore these errors, turn validation off with --validate=false

[machangwei@mcwk8s-master ~]$

[machangwei@mcwk8s-master ~]$ vim mcwJiankong.yml

[machangwei@mcwk8s-master ~]$ cat mcwJiankong.yml  #去掉副本数

apiVersion: apps/v1

kind: DaemonSet

metadata:

  name: mcw-prometheus-node-daemonset

spec:

  selector:

    matchLabels:

     app: mcw_prometheus

  template:

    metadata:

      labels:

        app: mcw_prometheus

    spec:

      hostNetwork: true

      containers:

        - name: mcw-pr-node

          image: prom/node-exporter

          imagePullPolicy: IfNotPresent

          command:

          - /bin/node_exporter

          - --pathprocfs

          - /host/proc

          - --path.sysfs

          - /host/sys

          - --collector.filesystem.ignored-mount-points

          - ^/(sys|proc|dev|host|etc)($|/)

          volumeMounts:

          - name: proc

            mountPath: /host/proc

          - name: sys

            mountPath: /host/sys

          - name: root

            mountPath: /rootfs

      volumes:

      - name: proc

        hostPath:

          path: /proc

      - name: sys

        hostPath:

          path: /sys

      - name: root

        hostPath:

          path: /

[machangwei@mcwk8s-master ~]$

[machangwei@mcwk8s-master ~]$

[machangwei@mcwk8s-master ~]$ kubectl apply -f mcwJiankong.yml

daemonset.apps/mcw-prometheus-node-daemonset created

[machangwei@mcwk8s-master ~]$ kubectl get daemonset #查看daemonset

NAME                            DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR   AGE

mcw-prometheus-node-daemonset   2         2         0       2            0           <none>          19s

[machangwei@mcwk8s-master ~]$ kubectl get pod -o wide  #查看pod，结果未能成功运行。不清楚原因，有时间再看这个问题

NAME                                  READY   STATUS             RESTARTS      AGE   IP         NODE           NOMINATED NODE   READINESS GATES

mcw-prometheus-node-daemonset-cv8k2   0/1     CrashLoopBackOff   2 (17s ago)   60s   10.0.0.5   mcwk8s-node1   <none>           <none>

mcw-prometheus-node-daemonset-z2vvc   0/1     Error              2 (30s ago)   60s   10.0.0.6   mcwk8s-node2   <none>           <none>

[machangwei@mcwk8s-master ~]$ kubectl describe pod mcw-prometheus-node-daemonset-cv8k2

Name:         mcw-prometheus-node-daemonset-cv8k2

Namespace:    default

Priority:     0

Node:         mcwk8s-node1/10.0.0.5

Start Time:   Tue, 18 Jan 2022 00:34:32 +0800

Labels:       app=mcw_prometheus

              controller-revision-hash=7b99d77578

              pod-template-generation=1

Annotations:  <none>

Status:       Running

IP:           10.0.0.5

IPs:

  IP:           10.0.0.5

Controlled By:  DaemonSet/mcw-prometheus-node-daemonset

Containers:

  mcw-pr-node:

    Container ID:  docker://7ff049b0c303ebb997c4794c9ffadbe7520f8cfdba71caec3b6b32c193ea1369

    Image:         prom/node-exporter

    Image ID:      docker-pullable://prom/node-exporter@sha256:f2269e73124dd0f60a7d19a2ce1264d33d08a985aed0ee6b0b89d0be470592cd

    Port:          <none>

    Host Port:     <none>

    Command:

      /bin/node_exporter

      --pathprocfs

      /host/proc

      --path.sysfs

      /host/sys

      --collector.filesystem.ignored-mount-points

      ^/(sys|proc|dev|host|etc)($|/)

    State:          Waiting

      Reason:       CrashLoopBackOff

    Last State:     Terminated

      Reason:       Error

      Exit Code:    1

      Started:      Tue, 18 Jan 2022 00:36:24 +0800

      Finished:     Tue, 18 Jan 2022 00:36:24 +0800

    Ready:          False

    Restart Count:  4

    Environment:    <none>

    Mounts:

      /host/proc from proc (rw)

      /host/sys from sys (rw)

      /rootfs from root (rw)

      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-w9bkl (ro)

Conditions:

  Type              Status

  Initialized       True

  Ready             False

  ContainersReady   False

  PodScheduled      True

Volumes:

  proc:

    Type:          HostPath (bare host directory volume)

    Path:          /proc

    HostPathType:

  sys:

    Type:          HostPath (bare host directory volume)

    Path:          /sys

    HostPathType:

  root:

    Type:          HostPath (bare host directory volume)

    Path:          /

    HostPathType:

  kube-api-access-w9bkl:

    Type:                    Projected (a volume that contains injected data from multiple sources)

    TokenExpirationSeconds:  3607

    ConfigMapName:           kube-root-ca.crt

    ConfigMapOptional:       <nil>

    DownwardAPI:             true

QoS Class:                   BestEffort

Node-Selectors:              <none>

Tolerations:                 node.kubernetes.io/disk-pressure:NoSchedule op=Exists

                             node.kubernetes.io/memory-pressure:NoSchedule op=Exists

                             node.kubernetes.io/network-unavailable:NoSchedule op=Exists

                             node.kubernetes.io/not-ready:NoExecute op=Exists

                             node.kubernetes.io/pid-pressure:NoSchedule op=Exists

                             node.kubernetes.io/unreachable:NoExecute op=Exists

                             node.kubernetes.io/unschedulable:NoSchedule op=Exists

Events:

  Type     Reason     Age                 From               Message

  ----     ------     ----                ----               -------

  Normal   Scheduled  2m36s               default-scheduler  Successfully assigned default/mcw-prometheus-node-daemonset-cv8k2 to mcwk8s-node1

  Normal   Pulling    2m36s               kubelet            Pulling image "prom/node-exporter"

  Normal   Pulled     2m9s                kubelet            Successfully pulled image "prom/node-exporter" in 27.526626918s

  Normal   Created    45s (x5 over 2m9s)  kubelet            Created container mcw-pr-node

  Normal   Started    45s (x5 over 2m8s)  kubelet            Started container mcw-pr-node

  Normal   Pulled     45s (x4 over 2m8s)  kubelet            Container image "prom/node-exporter" already present on machine

  Warning  BackOff    31s (x9 over 2m7s)  kubelet            Back-off restarting failed container

[machangwei@mcwk8s-master ~]$

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