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相较于Deployment资源，DaemonSet在每个节点仅运行一个副本，以提供守护服务。

查看DaemonSet类型的系统组件（kube-proxy和kube-flannel-ds-amd64）

获取kube-system命名空间的daemonset列表

[root@k8s01 ~]# kubectl get daemonsets.apps --namespace=kube-system 
NAME                      DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR            AGE
kube-flannel-ds-amd64     5         5         5       5            5           <none>                   6d16h
kube-flannel-ds-arm       0         0         0       0            0           <none>                   6d16h
kube-flannel-ds-arm64     0         0         0       0            0           <none>                   6d16h
kube-flannel-ds-ppc64le   0         0         0       0            0           <none>                   6d16h
kube-flannel-ds-s390x     0         0         0       0            0           <none>                   6d16h
kube-proxy                5         5         5       5            5           kubernetes.io/os=linux   6d16h
[root@k8s01 ~]#

获取kube-system命名空间pod列表详情（每个节点都运行一个daemonset类型容器副本）

[root@k8s01 ~]# kubectl get pods --namespace=kube-system -o wide
NAME                            READY   STATUS    RESTARTS   AGE     IP             NODE    NOMINATED NODE   READINESS GATES
coredns-66bff467f8-5x8nf        1/1     Running   0          6d16h   10.244.1.2     k8s02   <none>           <none>
coredns-66bff467f8-mgcd2        1/1     Running   0          6d16h   10.244.0.2     k8s01   <none>           <none>
etcd-k8s01                      1/1     Running   0          6d16h   172.31.14.12   k8s01   <none>           <none>
kube-apiserver-k8s01            1/1     Running   0          6d16h   172.31.14.12   k8s01   <none>           <none>
kube-controller-manager-k8s01   1/1     Running   0          6d16h   172.31.14.12   k8s01   <none>           <none>
kube-flannel-ds-amd64-4ngbr     1/1     Running   0          6d16h   172.31.6.113   k8s03   <none>           <none>
kube-flannel-ds-amd64-j9qmh     1/1     Running   0          4d      172.31.1.139   k8s04   <none>           <none>
kube-flannel-ds-amd64-kmw29     1/1     Running   0          6d16h   172.31.3.249   k8s02   <none>           <none>
kube-flannel-ds-amd64-l57kp     1/1     Running   0          6d16h   172.31.14.12   k8s01   <none>           <none>
kube-flannel-ds-amd64-rr8sv     1/1     Running   1          4d      172.31.15.1    k8s05   <none>           <none>
kube-proxy-22fd2                1/1     Running   0          6d16h   172.31.3.249   k8s02   <none>           <none>
kube-proxy-97hft                1/1     Running   0          4d      172.31.1.139   k8s04   <none>           <none>
kube-proxy-jwwp2                1/1     Running   0          6d16h   172.31.6.113   k8s03   <none>           <none>
kube-proxy-mw6xf                1/1     Running   0          4d      172.31.15.1    k8s05   <none>           <none>
kube-proxy-wnf4q                1/1     Running   0          6d16h   172.31.14.12   k8s01   <none>           <none>
kube-scheduler-k8s01            1/1     Running   0          6d16h   172.31.14.12   k8s01   <none>           <none>
[root@k8s01 ~]#

查看flannel网络组件配置文件中的daemonset配置

[root@k8s01 ~]# vi kube-flannel.yml
    134 apiVersion: apps/v1
    135 kind: DaemonSet
    136 metadata:
    137   name: kube-flannel-ds-amd64
    138   namespace: kube-system
    139   labels:
    140     tier: node
    141     app: flannel
    142 spec:
    143   selector:
    144     matchLabels:
    145       app: flannel
    146   template:
    147     metadata:
    148       labels:
    149         tier: node
    150         app: flannel
    151     spec:
    152       affinity:
    153         nodeAffinity:
    154           requiredDuringSchedulingIgnoredDuringExecution:
    155             nodeSelectorTerms:
    156               - matchExpressions:
    157                   - key: kubernetes.io/os
    158                     operator: In
    159                     values:
    160                       - linux
    161                   - key: kubernetes.io/arch
    162                     operator: In
    163                     values:
    164                       - amd64
    165       hostNetwork: true
    166       tolerations:
    167       - operator: Exists
    168         effect: NoSchedule
    169       serviceAccountName: flannel
    170       initContainers:
    171       - name: install-cni
    172         image: quay.io/coreos/flannel:v0.12.0-amd64
    173         command:
    174         - cp
    175         args:
    176         - -f
    177         - /etc/kube-flannel/cni-conf.json
    178         - /etc/cni/net.d/10-flannel.conflist
    179         volumeMounts:
    180         - name: cni
    181           mountPath: /etc/cni/net.d
    182         - name: flannel-cfg
    183           mountPath: /etc/kube-flannel/
    184       containers:
    185       - name: kube-flannel
    186         image: quay.io/coreos/flannel:v0.12.0-amd64
    187         command:
    188         - /opt/bin/flanneld
    189         args:
    190         - --ip-masq
    191         - --kube-subnet-mgr
    192         resources:
    193           requests:
    194             cpu: "100m"
    195             memory: "50Mi"
    196           limits:
    197             cpu: "100m"
    198             memory: "50Mi"
    199         securityContext:
    200           privileged: false
    201           capabilities:
    202             add: ["NET_ADMIN"]
    203         env:
    204         - name: POD_NAME
    205           valueFrom:
    206             fieldRef:
    207               fieldPath: metadata.name
    208         - name: POD_NAMESPACE
    209           valueFrom:
    210             fieldRef:
    211               fieldPath: metadata.namespace
    212         volumeMounts:
    213         - name: run
    214           mountPath: /run/flannel
    215         - name: flannel-cfg
    216           mountPath: /etc/kube-flannel/
    217       volumes:
    218         - name: run
    219           hostPath:
    220             path: /run/flannel
    221         - name: cni
    222           hostPath:
    223             path: /etc/cni/net.d
    224         - name: flannel-cfg
    225           configMap:
    226             name: kube-flannel-cfg

运行一个daemonset类型的资源（Fluentd日志收集系统）

[root@k8s01 ~]# vi daemonset.yaml
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:
      # this toleration is to have the daemonset runnable on master nodes
      # remove it if your masters can't run pods
      - key: node-role.kubernetes.io/master
        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

应用配置文件

[root@k8s01 ~]# kubectl apply -f daemonset.yaml 
daemonset.apps/fluentd-elasticsearch created
[root@k8s01 ~]# kubectl get daemonsets.apps 
No resources found in default namespace.
[root@k8s01 ~]# kubectl get daemonsets.apps --namespace=kube-system 
NAME                      DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR            AGE
fluentd-elasticsearch     5         5         5       5            5           <none>                   28s
kube-flannel-ds-amd64     5         5         5       5            5           <none>                   6d18h
kube-flannel-ds-arm       0         0         0       0            0           <none>                   6d18h
kube-flannel-ds-arm64     0         0         0       0            0           <none>                   6d18h
kube-flannel-ds-ppc64le   0         0         0       0            0           <none>                   6d18h
kube-flannel-ds-s390x     0         0         0       0            0           <none>                   6d18h
kube-proxy                5         5         5       5            5           kubernetes.io/os=linux   6d18h
[root@k8s01 ~]#

获取kube-system命名空间的daemonset列表

[root@k8s01 ~]# kubectl get pods --namespace=kube-system -o wide
NAME                            READY   STATUS    RESTARTS   AGE     IP             NODE    NOMINATED NODE   READINESS GATES
coredns-66bff467f8-5x8nf        1/1     Running   0          6d18h   10.244.1.2     k8s02   <none>           <none>
coredns-66bff467f8-mgcd2        1/1     Running   0          6d18h   10.244.0.2     k8s01   <none>           <none>
etcd-k8s01                      1/1     Running   0          6d18h   172.31.14.12   k8s01   <none>           <none>
fluentd-elasticsearch-64c2h     1/1     Running   0          84s     10.244.5.9     k8s05   <none>           <none>
fluentd-elasticsearch-f8989     1/1     Running   0          84s     10.244.0.3     k8s01   <none>           <none>
fluentd-elasticsearch-lcgn7     1/1     Running   0          84s     10.244.3.4     k8s04   <none>           <none>
fluentd-elasticsearch-ss2zm     1/1     Running   0          84s     10.244.1.20    k8s02   <none>           <none>
fluentd-elasticsearch-wkd45     1/1     Running   0          84s     10.244.2.39    k8s03   <none>           <none>
kube-apiserver-k8s01            1/1     Running   0          6d18h   172.31.14.12   k8s01   <none>           <none>
kube-controller-manager-k8s01   1/1     Running   0          6d18h   172.31.14.12   k8s01   <none>           <none>
kube-flannel-ds-amd64-4ngbr     1/1     Running   0          6d18h   172.31.6.113   k8s03   <none>           <none>
kube-flannel-ds-amd64-j9qmh     1/1     Running   0          4d2h    172.31.1.139   k8s04   <none>           <none>
kube-flannel-ds-amd64-kmw29     1/1     Running   0          6d18h   172.31.3.249   k8s02   <none>           <none>
kube-flannel-ds-amd64-l57kp     1/1     Running   0          6d18h   172.31.14.12   k8s01   <none>           <none>
kube-flannel-ds-amd64-rr8sv     1/1     Running   1          4d2h    172.31.15.1    k8s05   <none>           <none>
kube-proxy-22fd2                1/1     Running   0          6d18h   172.31.3.249   k8s02   <none>           <none>
kube-proxy-97hft                1/1     Running   0          4d2h    172.31.1.139   k8s04   <none>           <none>
kube-proxy-jwwp2                1/1     Running   0          6d18h   172.31.6.113   k8s03   <none>           <none>
kube-proxy-mw6xf                1/1     Running   0          4d2h    172.31.15.1    k8s05   <none>           <none>
kube-proxy-wnf4q                1/1     Running   0          6d18h   172.31.14.12   k8s01   <none>           <none>
kube-scheduler-k8s01            1/1     Running   0          6d18h   172.31.14.12   k8s01   <none>           <none>
[root@k8s01 ~]#

为集群新增节点

172.31.3.209 k8s01
172.31.8.132 k8s02
172.31.10.229 k8s03
172.31.1.139 k8s04
172.31.15.1 k8s05

新节点加入集群

kubeadm join --token <token> <control-plane-host>:<control-plane-port> --discovery-token-ca-cert-hash sha256:<hash>

主节点生成token有效期为24小时，超过该有效期后需要另行生成。

查看现有token列表

[root@k8s01 ~]# kubeadm token list
TOKEN                     TTL         EXPIRES                USAGES                   DESCRIPTION                                                EXTRA GROUPS
ca673s.97ektx8klpsjfovt   8h          2020-04-23T10:35:25Z   authentication,signing   <none>                                                     system:bootstrappers:kubeadm:default-node-token
qxycbf.ri8i2zygahp5je8m   8h          2020-04-23T10:35:43Z   authentication,signing   <none>                                                     system:bootstrappers:kubeadm:default-node-token
[root@k8s01 ~]#

重新生成token

[root@k8s01 ~]# kubeadm token create
W0423 02:26:28.166475    9469 configset.go:202] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io]
lf1qej.q4wq7xo23xigg672
[root@k8s01 ~]# kubeadm token list
TOKEN                     TTL         EXPIRES                USAGES                   DESCRIPTION                                                EXTRA GROUPS
ca673s.97ektx8klpsjfovt   8h          2020-04-23T10:35:25Z   authentication,signing   <none>                                                     system:bootstrappers:kubeadm:default-node-token
lf1qej.q4wq7xo23xigg672   23h         2020-04-24T02:26:28Z   authentication,signing   <none>                                                     system:bootstrappers:kubeadm:default-node-token
qxycbf.ri8i2zygahp5je8m   8h          2020-04-23T10:35:43Z   authentication,signing   <none>                                                     system:bootstrappers:kubeadm:default-node-token
[root@k8s01 ~]#

重新生成hash值（该值不变）

openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | \
openssl dgst -sha256 -hex | sed 's/^.* //'

[root@k8s01 ~]# openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | \
> openssl dgst -sha256 -hex | sed 's/^.* //'
d435ee7f3795a10b58762be903a78a99c719e3520fb029d718505095b37e9859
[root@k8s01 ~]#

节点4加入

[root@k8s04 ~]# kubeadm join --token lf1qej.q4wq7xo23xigg672 172.31.14.12:6443 --discovery-token-ca-cert-hash sha256:d435ee7f3795a10b58762be903a78a99c719e3520fb029d718505095b37e9859
W0423 02:28:44.283472 19177 join.go:346] [preflight] WARNING: JoinControlPane.controlPlane settings will be ignored when control-plane flag is not set.
[preflight] Running pre-flight checks
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
[kubelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.18" ConfigMap in the kube-system namespace
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the control-plane to see this node join the cluster.

[root@k8s04 ~]#

节点5加入

[root@k8s05 ~]# kubeadm join --token lf1qej.q4wq7xo23xigg672 172.31.14.12:6443 --discovery-token-ca-cert-hash sha256:d435ee7f3795a10b58762be903a78a99c719e3520fb029d718505095b37e9859
W0423 02:28:51.716851 19271 join.go:346] [preflight] WARNING: JoinControlPane.controlPlane settings will be ignored when control-plane flag is not set.
[preflight] Running pre-flight checks
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
[kubelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.18" ConfigMap in the kube-system namespace
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the control-plane to see this node join the cluster.

[root@k8s05 ~]#

获取节点列表（加入成功）

[root@k8s01 ~]# kubectl get nodes -o wide
NAME    STATUS   ROLES    AGE     VERSION   INTERNAL-IP    EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION                CONTAINER-RUNTIME
k8s01   Ready    master   2d16h   v1.18.2   172.31.14.12   <none>        CentOS Linux 7 (Core)   3.10.0-1062.12.1.el7.x86_64   docker://19.3.8
k8s02   Ready    <none>   2d16h   v1.18.2   172.31.3.249   <none>        CentOS Linux 7 (Core)   3.10.0-1062.12.1.el7.x86_64   docker://19.3.8
k8s03   Ready    <none>   2d16h   v1.18.2   172.31.6.113   <none>        CentOS Linux 7 (Core)   3.10.0-1062.12.1.el7.x86_64   docker://19.3.8
k8s04   Ready    <none>   78s     v1.18.2   172.31.1.139   <none>        CentOS Linux 7 (Core)   3.10.0-1062.12.1.el7.x86_64   docker://19.3.8
k8s05   Ready    <none>   70s     v1.18.2   172.31.15.1    <none>        CentOS Linux 7 (Core)   3.10.0-1062.12.1.el7.x86_64   docker://19.3.8
[root@k8s01 ~]#

创建新token并生成完整节点加入命令（一次性）

[root@k8s01 ~]# kubeadm token list
TOKEN                     TTL         EXPIRES                USAGES                   DESCRIPTION                                                EXTRA GROUPS
ca673s.97ektx8klpsjfovt   7h          2020-04-23T10:35:25Z   authentication,signing   <none>                                                     system:bootstrappers:kubeadm:default-node-token
lf1qej.q4wq7xo23xigg672   23h         2020-04-24T02:26:28Z   authentication,signing   <none>                                                     system:bootstrappers:kubeadm:default-node-token
qxycbf.ri8i2zygahp5je8m   7h          2020-04-23T10:35:43Z   authentication,signing   <none>                                                     system:bootstrappers:kubeadm:default-node-token
[root@k8s01 ~]# kubeadm token create --print-join-command
W0423 02:41:47.487117   15377 configset.go:202] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io]
kubeadm join 172.31.14.12:6443 --token vc6toc.jhhp9jatexn4ed7m     --discovery-token-ca-cert-hash sha256:d435ee7f3795a10b58762be903a78a99c719e3520fb029d718505095b37e9859 
[root@k8s01 ~]# kubeadm token list
TOKEN                     TTL         EXPIRES                USAGES                   DESCRIPTION                                                EXTRA GROUPS
ca673s.97ektx8klpsjfovt   7h          2020-04-23T10:35:25Z   authentication,signing   <none>                                                     system:bootstrappers:kubeadm:default-node-token
lf1qej.q4wq7xo23xigg672   23h         2020-04-24T02:26:28Z   authentication,signing   <none>                                                     system:bootstrappers:kubeadm:default-node-token
qxycbf.ri8i2zygahp5je8m   7h          2020-04-23T10:35:43Z   authentication,signing   <none>                                                     system:bootstrappers:kubeadm:default-node-token
vc6toc.jhhp9jatexn4ed7m   23h         2020-04-24T02:41:47Z   authentication,signing   <none>                                                     system:bootstrappers:kubeadm:default-node-token
[root@k8s01 ~]#