K8S简介+CentOS7 部署K8S集群

一、前言

• Kubernetes（简称K8S）是开源的容器集群管理系统，可以实现容器集群的自动化部署、自动扩缩容、维护等功能。它既是一款容器编排工具，也是全新的基于容器技术的分布式架构领先方案。在Docker技术的基础上，为容器化的应用提供部署运行、资源调度、服务发现和动态伸缩等功能，提高了大规模容器集群管理的便捷性。【Kubernetes是容器集群管理工具】

二、Kubernetes的架构图

 三、重要概念

 3.1、cluster

• cluster是 计算、存储和网络资源的集合，k8s利用这些资源运行各种基于容器的应用。

3.2、master

• master是cluster的大脑，他的主要职责是调度，即决定将应用放在那里运行。master运行linux操作系统，可以是物理机或者虚拟机。为了实现高可用，可以运行多个master。

3.3、node

• node的职责是运行容器应用。node由master管理，node负责监控并汇报容器的状态，同时根据master的要求管理容器的生命周期。node运行在linux的操作系统上，可以是物理机或者是虚拟机。

3.4、pod

• pod是k8s的最小工作单元。每个pod包含一个或者多个容器。pod中的容器会作为一个整体被master调度到一个node上运行。

3.5、controller

• k8s通常不会直接创建pod,而是通过controller来管理pod的。controller中定义了pod的部署特性，比如有几个剧本，在什么样的node上运行等。为了满足不同的业务场景，k8s提供了多种controller，包括deployment、replicaset、daemonset、statefulset、job等。

3.6、deployment

• 是最常用的controller。deployment可以管理pod的多个副本，并确保pod按照期望的状态运行。

3.7、replicaset

• 实现了pod的多副本管理。使用deployment时会自动创建replicaset，也就是说deployment是通过replicaset来管理pod的多个副本的，我们通常不需要直接使用replicaset。

3.8、daemonset

• 用于每个node最多只运行一个pod副本的场景。正如其名称所示的，daemonset通常用于运行daemon。

3.9、statefuleset

• 能够保证pod的每个副本在整个生命周期中名称是不变的，而其他controller不提供这个功能。当某个pod发生故障需要删除并重新启动时，pod的名称会发生变化，同时statefulset会保证副本按照固定的顺序启动、更新或者删除。

3.10、job

• 用于运行结束就删除的应用，而其他controller中的pod通常是长期持续运行的。

3.11、service

• k8s的 service定义了外界访问一组特定pod的方式。service有自己的IP和端口，service为pod提供了负载均衡。
• k8s运行容器pod与访问容器这两项任务分别由controller和service执行。

3.12、namespace

• 可以将一个物理的cluster逻辑上划分成多个虚拟cluster，每个cluster就是一个namespace。不同的namespace里的资源是完全隔离的。

四、安装部署K8S集群

备注：第2步~第9步，所有的节点都要操作，第10、11步Master节点操作，第12步Node节点操作。

           如果第10、11、12步操作失败，可以通过 kubeadm reset 命令来清理环境重新安装。

4.1、机器准备

机器IP	hostname
192.168.182.135	k8s-master
192.168.182.136	k8s-node1
192.168.182.137	k8s-node2

4.2、关闭防火墙

• systemctl stop firewalld
• systemctl disable firewalld

4.3、关闭selinux

• setenforce 0  # 临时关闭
• sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config # 永久关闭

4.4、关闭swap

1. swapoff -a    # 临时关闭；关闭swap主要是为了性能考虑
   
2.  free             # 可以通过这个命令查看swap是否关闭了
3. sed -ri 's/.*swap.*/#&/' /etc/fstab  # 永久关闭

4.5、添加主机名与IP对应的关系

• $ vim /etc/hosts
•  添加如下内容：

192.168.182.135     k8s-master
192.168.182.136     k8s-node1
192.168.182.137     k8s-node2

修改主机名

k8s-master:

[root@localhost ~]# hostname
localhost.localdomain
[root@localhost ~]# hostname k8s-master ##临时生效
[root@localhost ~]# hostnamectl set-hostname k8s-master ##重启后永久生效

k8s-node1:

[root@localhost ~]# hostname
localhost.localdomain
[root@localhost ~]# hostname k8s-node1##临时生效
[root@localhost ~]# hostnamectl set-hostname k8s-node1##重启后永久生效

k8s-node2:

[root@localhost ~]# hostname
localhost.localdomain
[root@localhost ~]# hostname k8s-node2 ##临时生效
[root@localhost ~]# hostnamectl set-hostname k8s-node2 ##重启后永久生效

4.6、将桥接的IPV4流量传递到iptables 的链

$ cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
$ sysctl --system

4.7、安装Docker

# 添加docker yum源
$ wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O/etc/yum.repos.d/docker-ce.repo
# 安装
$ yum -y install docker-ce
# 设置开机启动
$ systemctl enable docker
# 启动docker
$ systemctl start docker

4.8、添加阿里云YUM软件源

cat > /etc/yum.repos.d/kubernetes.repo << EOF
[k8s]
name=k8s
enabled=1
gpgcheck=0
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
EOF

4.9、安装kubeadm，kubelet和kubectl

kubelet # 运行在 Cluster 所有节点上，负责启动 Pod 和容器。

kubeadm # 用于初始化 Cluster。

kubectl # 是 Kubernetes 命令行工具。通过 kubectl 可以部署和管理应用，查看各种资源，创建、删除和更新各种组件。

• 在部署kubernetes时，要求master node和worker node上的版本保持一致，否则会出现版本不匹配导致奇怪的问题出现。本文将介绍如何在CentOS系统上，使用yum安装指定版本的Kubernetes。
• 我们需要安装指定版本的kubernetes。那么如何做呢？在进行yum安装时，可以使用下列的格式来进行安装：
• yum install -y kubelet-<version> kubectl-<version> kubeadm-<version>

# 这里安装最新的
$ yum install kubelet kubeadm kubectl -y
# 最后安装的版本为：kubeadm.x86_64 0:1.17.0-0；kubectl.x86_64 0:1.17.0-0；kubelet.x86_64 0:1.17.0-0

• 启动kubelet

# 此时，还不能启动kubelet，因为此时配置还不能，现在仅仅可以设置开机自启动
$ systemctl enable kubelet

4.10、部署Kubernetes Master

1）初始化kubeadm

$ kubeadm init
  --apiserver-advertise-address=192.168.182.135
  --image-repository registry.aliyuncs.com/google_containers
  --kubernetes-version v1.17.0 
  --service-cidr=10.1.0.0/16
  --pod-network-cidr=10.244.0.0/16

# –image-repository string：    这个用于指定从什么位置来拉取镜像（1.13版本才有的），默认值是k8s.gcr.io，我们将其指定为国内镜像地址：registry.aliyuncs.com/google_containers
# –kubernetes-version string：  指定kubenets版本号，默认值是stable-1，会导致从https://dl.k8s.io/release/stable-1.txt下载最新的版本号，我们可以将其指定为固定版本（v1.15.1）来跳过网络请求。
# –apiserver-advertise-address  指明用 Master 的哪个 interface 与 Cluster 的其他节点通信。如果 Master 有多个 interface，建议明确指定，如果不指定，kubeadm 会自动选择有默认网关的 interface。
# –pod-network-cidr             指定 Pod 网络的范围。Kubernetes 支持多种网络方案，而且不同网络方案对  –pod-network-cidr有自己的要求，这里设置为10.244.0.0/16 是因为我们将使用 flannel 网络方案，必须设置成这个 CIDR。

注意：

1. 建议至少2 cpu ,2G，非硬性要求，1cpu，1G也可以搭建起集群。但是：
2. 1个cpu的话初始化master的时候会报 [WARNING NumCPU]: the number of available CPUs 1 is less than the required 2
3. 部署插件或者pod时可能会报warning：FailedScheduling：Insufficient cpu, Insufficient memory
4. 如果出现这种提示，说明你的虚拟机分配的CPU为1核，需要重新设置虚拟机master节点内核数。

最后初始化成功：

# 其它node节点执行，如果重置了，就不一样了，得根据上面执行情况（node）

kubeadm join 192.168.182.135:6443 --token 7rpjfp.n3vg39zrgstzr0rs
--discovery-token-ca-cert-hash sha256:8c5aa1a4e82e70fed62b02e8d7bff54c801251b5ee40c7cec68a8c214dcc1234

$  docker images 

 

 2）使用kubectl工具

复制如下命令直接执行（master）

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config　　

下面就可以直接使用kubectl命令了（master）

 4.11、安装Pod网络插件（CNI）(master)

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
或者：
kubectl apply -f kube-flannel.yml

$ cat kube-flannel.yml

---
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
  name: psp.flannel.unprivileged
  annotations:
    seccomp.security.alpha.kubernetes.io/allowedProfileNames: docker/default
    seccomp.security.alpha.kubernetes.io/defaultProfileName: docker/default
    apparmor.security.beta.kubernetes.io/allowedProfileNames: runtime/default
    apparmor.security.beta.kubernetes.io/defaultProfileName: runtime/default
spec:
  privileged: false
  volumes:
    - configMap
    - secret
    - emptyDir
    - hostPath
  allowedHostPaths:
    - pathPrefix: "/etc/cni/net.d"
    - pathPrefix: "/etc/kube-flannel"
    - pathPrefix: "/run/flannel"
  readOnlyRootFilesystem: false
  # Users and groups
  runAsUser:
    rule: RunAsAny
  supplementalGroups:
    rule: RunAsAny
  fsGroup:
    rule: RunAsAny
  # Privilege Escalation
  allowPrivilegeEscalation: false
  defaultAllowPrivilegeEscalation: false
  # Capabilities
  allowedCapabilities: ['NET_ADMIN']
  defaultAddCapabilities: []
  requiredDropCapabilities: []
  # Host namespaces
  hostPID: false
  hostIPC: false
  hostNetwork: true
  hostPorts:
  - min: 0
    max: 65535
  # SELinux
  seLinux:
    # SELinux is unused in CaaSP
    rule: 'RunAsAny'
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: flannel
rules:
  - apiGroups: ['extensions']
    resources: ['podsecuritypolicies']
    verbs: ['use']
    resourceNames: ['psp.flannel.unprivileged']
  - apiGroups:
      - ""
    resources:
      - pods
    verbs:
      - get
  - apiGroups:
      - ""
    resources:
      - nodes
    verbs:
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - nodes/status
    verbs:
      - patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: flannel
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: flannel
subjects:
- kind: ServiceAccount
  name: flannel
  namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: flannel
  namespace: kube-system
---
kind: ConfigMap
apiVersion: v1
metadata:
  name: kube-flannel-cfg
  namespace: kube-system
  labels:
    tier: node
    app: flannel
data:
  cni-conf.json: |
    {
      "name": "cbr0",
      "cniVersion": "0.3.1",
      "plugins": [
        {
          "type": "flannel",
          "delegate": {
            "hairpinMode": true,
            "isDefaultGateway": true
          }
        },
        {
          "type": "portmap",
          "capabilities": {
            "portMappings": true
          }
        }
      ]
    }
  net-conf.json: |
    {
      "Network": "10.244.0.0/16",
      "Backend": {
        "Type": "vxlan"
      }
    }
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: kube-flannel-ds-amd64
  namespace: kube-system
  labels:
    tier: node
    app: flannel
spec:
  selector:
    matchLabels:
      app: flannel
  template:
    metadata:
      labels:
        tier: node
        app: flannel
    spec:
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
              - matchExpressions:
                  - key: beta.kubernetes.io/os
                    operator: In
                    values:
                      - linux
                  - key: beta.kubernetes.io/arch
                    operator: In
                    values:
                      - amd64
      hostNetwork: true
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: quay.io/coreos/flannel:v0.11.0-amd64
        command:
        - cp
        args:
        - -f
        - /etc/kube-flannel/cni-conf.json
        - /etc/cni/net.d/10-flannel.conflist
        volumeMounts:
        - name: cni
          mountPath: /etc/cni/net.d
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      containers:
      - name: kube-flannel
        image: quay.io/coreos/flannel:v0.11.0-amd64
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            cpu: "100m"
            memory: "50Mi"
          limits:
            cpu: "100m"
            memory: "50Mi"
        securityContext:
          privileged: false
          capabilities:
            add: ["NET_ADMIN"]
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        volumeMounts:
        - name: run
          mountPath: /run/flannel
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      volumes:
        - name: run
          hostPath:
            path: /run/flannel
        - name: cni
          hostPath:
            path: /etc/cni/net.d
        - name: flannel-cfg
          configMap:
            name: kube-flannel-cfg
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: kube-flannel-ds-arm64
  namespace: kube-system
  labels:
    tier: node
    app: flannel
spec:
  selector:
    matchLabels:
      app: flannel
  template:
    metadata:
      labels:
        tier: node
        app: flannel
    spec:
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
              - matchExpressions:
                  - key: beta.kubernetes.io/os
                    operator: In
                    values:
                      - linux
                  - key: beta.kubernetes.io/arch
                    operator: In
                    values:
                      - arm64
      hostNetwork: true
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: quay.io/coreos/flannel:v0.11.0-arm64
        command:
        - cp
        args:
        - -f
        - /etc/kube-flannel/cni-conf.json
        - /etc/cni/net.d/10-flannel.conflist
        volumeMounts:
        - name: cni
          mountPath: /etc/cni/net.d
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      containers:
      - name: kube-flannel
        image: quay.io/coreos/flannel:v0.11.0-arm64
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            cpu: "100m"
            memory: "50Mi"
          limits:
            cpu: "100m"
            memory: "50Mi"
        securityContext:
          privileged: false
          capabilities:
             add: ["NET_ADMIN"]
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        volumeMounts:
        - name: run
          mountPath: /run/flannel
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      volumes:
        - name: run
          hostPath:
            path: /run/flannel
        - name: cni
          hostPath:
            path: /etc/cni/net.d
        - name: flannel-cfg
          configMap:
            name: kube-flannel-cfg
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: kube-flannel-ds-arm
  namespace: kube-system
  labels:
    tier: node
    app: flannel
spec:
  selector:
    matchLabels:
      app: flannel
  template:
    metadata:
      labels:
        tier: node
        app: flannel
    spec:
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
              - matchExpressions:
                  - key: beta.kubernetes.io/os
                    operator: In
                    values:
                      - linux
                  - key: beta.kubernetes.io/arch
                    operator: In
                    values:
                      - arm
      hostNetwork: true
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: quay.io/coreos/flannel:v0.11.0-arm
        command:
        - cp
        args:
        - -f
        - /etc/kube-flannel/cni-conf.json
        - /etc/cni/net.d/10-flannel.conflist
        volumeMounts:
        - name: cni
          mountPath: /etc/cni/net.d
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      containers:
      - name: kube-flannel
        image: quay.io/coreos/flannel:v0.11.0-arm
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            cpu: "100m"
            memory: "50Mi"
          limits:
            cpu: "100m"
            memory: "50Mi"
        securityContext:
          privileged: false
          capabilities:
             add: ["NET_ADMIN"]
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        volumeMounts:
        - name: run
          mountPath: /run/flannel
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      volumes:
        - name: run
          hostPath:
            path: /run/flannel
        - name: cni
          hostPath:
            path: /etc/cni/net.d
        - name: flannel-cfg
          configMap:
            name: kube-flannel-cfg
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: kube-flannel-ds-ppc64le
  namespace: kube-system
  labels:
    tier: node
    app: flannel
spec:
  selector:
    matchLabels:
      app: flannel
  template:
    metadata:
      labels:
        tier: node
        app: flannel
    spec:
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
              - matchExpressions:
                  - key: beta.kubernetes.io/os
                    operator: In
                    values:
                      - linux
                  - key: beta.kubernetes.io/arch
                    operator: In
                    values:
                      - ppc64le
      hostNetwork: true
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: quay.io/coreos/flannel:v0.11.0-ppc64le
        command:
        - cp
        args:
        - -f
        - /etc/kube-flannel/cni-conf.json
        - /etc/cni/net.d/10-flannel.conflist
        volumeMounts:
        - name: cni
          mountPath: /etc/cni/net.d
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      containers:
      - name: kube-flannel
        image: quay.io/coreos/flannel:v0.11.0-ppc64le
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            cpu: "100m"
            memory: "50Mi"
          limits:
            cpu: "100m"
            memory: "50Mi"
        securityContext:
          privileged: false
          capabilities:
             add: ["NET_ADMIN"]
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        volumeMounts:
        - name: run
          mountPath: /run/flannel
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      volumes:
        - name: run
          hostPath:
            path: /run/flannel
        - name: cni
          hostPath:
            path: /etc/cni/net.d
        - name: flannel-cfg
          configMap:
            name: kube-flannel-cfg
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: kube-flannel-ds-s390x
  namespace: kube-system
  labels:
    tier: node
    app: flannel
spec:
  selector:
    matchLabels:
      app: flannel
  template:
    metadata:
      labels:
        tier: node
        app: flannel
    spec:
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
              - matchExpressions:
                  - key: beta.kubernetes.io/os
                    operator: In
                    values:
                      - linux
                  - key: beta.kubernetes.io/arch
                    operator: In
                    values:
                      - s390x
      hostNetwork: true
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: quay.io/coreos/flannel:v0.11.0-s390x
        command:
        - cp
        args:
        - -f
        - /etc/kube-flannel/cni-conf.json
        - /etc/cni/net.d/10-flannel.conflist
        volumeMounts:
        - name: cni
          mountPath: /etc/cni/net.d
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      containers:
      - name: kube-flannel
        image: quay.io/coreos/flannel:v0.11.0-s390x
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            cpu: "100m"
            memory: "50Mi"
          limits:
            cpu: "100m"
            memory: "50Mi"
        securityContext:
          privileged: false
          capabilities:
             add: ["NET_ADMIN"]
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        volumeMounts:
        - name: run
          mountPath: /run/flannel
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      volumes:
        - name: run
          hostPath:
            path: /run/flannel
        - name: cni
          hostPath:
            path: /etc/cni/net.d
        - name: flannel-cfg
          configMap:
            name: kube-flannel-cfg

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 2）查看是否部署成功

 3）再次查看node，可以看到状态为ready

 12、Node节点加入集群（node）

• 向集群添加新节点，执行在kubeadm init输出的kubeadm join命令：
• 复制上面命令，在node节点上执行，记得更换对应的ip
• 这里的–token 来自前面kubeadm init输出提示，如果当时没有记录下来可以通过kubeadm token list 查看。

kubeadm join 192.168.182.135:6443 --token 7rpjfp.n3vg39zrgstzr0rs 
--discovery-token-ca-cert-hash sha256:8c5aa1a4e82e70fed62b02e8d7bff54c801251b5ee40c7cec68a8c214dcc1234

 在master端查看：

 

注意：重新初始化得先执行这几步

docker rm -f `docker ps -a -q`
rm -rf /etc/kubernetes/*
rm -rf /var/lib/etcd/
kubeadm reset

问题1：No networks found in /etc/cni/net.d

• 解决：cat /etc/cni/net.d/10-flannel.conflist
• 

  {
    "name": "cbr0",
    "cniVersion": "0.3.1",
    "plugins": [
      {
        "type": "flannel",
        "delegate": {
          "hairpinMode": true,
          "isDefaultGateway": true
        }
      },
      {
        "type": "portmap",
        "capabilities": {
          "portMappings": true
        }
      }
    ]
  }

  View Code

问题2：如果出现如下错误提示：

•  
• 解决：

• # 更改docker的启动参数
  $ vim /usr/lib/systemd/system/docker.service
  #ExecStart=/usr/bin/dockerd
  ExecStart=/usr/bin/dockerd --exec-opt native.cgroupdriver=systemd
  # 重启docker
  $ systemctl daemon-reload
  $ systemctl restart docker

13、补充：移除NODE节点的方法（master执行）

 第一步：先将节点设置为维护模式(k8s-node1是节点名称)

[root@k8s-master ~]# kubectl drain k8s-node1 --delete-local-data --force --ignore-daemonsets
node/k8s-node1 cordoned
node/k8s-node1 drained

第二步：然后删除节点

[root@k8s-master ~]# kubectl delete node k8s-node1
node "k8s-node1" deleted

第三步：查看节点

[root@k8s-master ~]# kubectl get nodes
NAME         STATUS   ROLES    AGE    VERSION
k8s-master   Ready    master   18m    v1.17.0
k8s-node2    Ready    <none>   5m7s   v1.17.0

发现k8s-node1节点已经被删除了

14、如果这个时候再想添加进来这个node，需要执行两步操作

第一步：停掉kubelet(需要添加进来的节点操作)

[root@k8s-node2 ~]# systemctl stop kubelet

第二步：删除相关文件

[root@k8s-node2 ~]# rm -rf /etc/kubernetes/*

第三步：添加节点

kubeadm join 192.168.182.135:6443 --token 7rpjfp.n3vg39zrgstzr0rs 
--discovery-token-ca-cert-hash sha256:8c5aa1a4e82e70fed62b02e8d7bff54c801251b5ee40c7cec68a8c214dcc1234

第四步：查看节点

[root@k8s-master ~]# kubectl get nodes
NAME         STATUS     ROLES    AGE   VERSION
k8s-master   Ready      master   24m   v1.17.0
k8s-node1    NotReady   <none>   6s    v1.17.0
k8s-node2    Ready      <none>   10m   v1.17.0

15、忘掉token再次添加进k8s集群

第一步：主节点执行命令

获取token

[root@k8s-master ~]# kubeadm token list
TOKEN                     TTL         EXPIRES                     USAGES                   DESCRIPTION                                                EXTRA GROUPS
7rpjfp.n3vg39zrgstzr0rs   23h         2019-12-30T20:01:50+08:00   authentication,signing   The default bootstrap token generated by 'kubeadm init'.   system:bootstrappers:kubeadm:default-node-token

第二步： 获取ca证书sha256编码hash值

[root@k8s-master ~]# openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed 's/^.* //'
8c5aa1a4e82e70fed62b02e8d7bff54c801251b5ee40c7cec68a8c214dcc1234

第三步：从节点执行如下的命令

[root@k8s-master ~]# systemctl stop kubelet

第四步：删除相关文件

[root@k8s-master ~]# rm -rf /etc/kubernetes/*

第五步：加入集群

指定主节点IP，端口是6443

在生成的证书前有sha256:

kubeadm join 192.168.64.10:6443 --token 7rpjfp.n3vg39zrgstzr0rs  --discovery-token-ca-cert-hash sha256:8c5aa1a4e82e70fed62b02e8d7bff54c801251b5ee40c7cec68a8c214dcc1234

16、常用命令

16.1、查看node

# -o wide以yaml格式显示详细信息
kubectl get node -o wide

16.2、创建deployments

kubectl run net-test --image=alpine --replicas=2 sleep 10

16.3、查看deployments详情

kubectl describe deployment net-test

16.4、删除deployments

kubectl delete deployment net-test -n default

16.5、查看pod

kubectl get pod -o wide

16.6、查看pod的详情

kubectl describe pod net-test-5767cb94df-7lwtq

16.7、手动扩容缩容

# 通过执行扩容命令，对某个deployment直接进行扩容：
$ kubectl  scale deployment net-test --replicas=4

# 当要缩容，减少副本数量即可：
$ kubectl  scale deployment net-test --replicas=2

17、搭建K8S Dashboard

1. 下载dashboard文件：

curl -o kubernetes-dashboard.yaml  https://raw.githubusercontent.com/kubernetes/dashboard/master/aio/deploy/recommended/kubernetes-dashboard.yaml

如果地址不可用可以使用下面的【kubernetes-dashboard.yaml】文件：对外端口为nodePort

apiVersion: v1
kind: Secret
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard-certs
  namespace: kube-system
type: Opaque
---
apiVersion: v1
kind: ServiceAccount
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kube-system
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: kubernetes-dashboard-minimal
  namespace: kube-system
rules:
- apiGroups: [""]
  resources: ["secrets"]
  verbs: ["create"]
- apiGroups: [""]
  resources: ["configmaps"]
  verbs: ["create"]
- apiGroups: [""]
  resources: ["secrets"]
  resourceNames: ["kubernetes-dashboard-key-holder", "kubernetes-dashboard-certs"]
  verbs: ["get", "update", "delete"]
- apiGroups: [""]
  resources: ["configmaps"]
  resourceNames: ["kubernetes-dashboard-settings"]
  verbs: ["get", "update"]
- apiGroups: [""]
  resources: ["services"]
  resourceNames: ["heapster"]
  verbs: ["proxy"]
- apiGroups: [""]
  resources: ["services/proxy"]
  resourceNames: ["heapster", "http:heapster:", "https:heapster:"]
  verbs: ["get"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: kubernetes-dashboard-minimal
  namespace: kube-system
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: kubernetes-dashboard
  namespace: kube-system
---
kind: Deployment
apiVersion: apps/v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kube-system
spec:
  replicas: 1
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      k8s-app: kubernetes-dashboard
  template:
    metadata:
      labels:
        k8s-app: kubernetes-dashboard
    spec:
      containers:
      - name: kubernetes-dashboard
        image: 192.168.182.135:9090/library/kubernetes-dashboard-amd64:v1.8.3
        ports:
        - containerPort: 8443
          protocol: TCP
        args:
          - --auto-generate-certificates
        volumeMounts:
        - name: kubernetes-dashboard-certs
          mountPath: /certs
        - mountPath: /tmp
          name: tmp-volume
        livenessProbe:
          httpGet:
            scheme: HTTPS
            path: /
            port: 8443
          initialDelaySeconds: 30
          timeoutSeconds: 30
      volumes:
      - name: kubernetes-dashboard-certs
        secret:
          secretName: kubernetes-dashboard-certs
      - name: tmp-volume
        emptyDir: {}
      serviceAccountName: kubernetes-dashboard
      tolerations:
      - key: node-role.kubernetes.io/master
        effect: NoSchedule
---
kind: Service
apiVersion: v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kube-system
spec:
  type: NodePort
  ports:
    - port: 443
      targetPort: 8443
      nodePort: 31080
  selector:
    k8s-app: kubernetes-dashboard

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2.下载镜像镜像【k8s.gcr.io#kubernetes-dashboard-amd64.tar】

链接: https://pan.baidu.com/s/1vQUGpx89TZw-HyxCVE972w 提取码: 5pui 复制这段内容后打开百度网盘手机App，操作更方便哦

3. 创建kubernetes-dashboard：注意：修改【kubernetes-dashboard.yaml】文件里面的镜像地址

kubectl create -f kubernetes-dashboard.yaml

4. 由于我之前安装过一次，所以报错：

Error from server (AlreadyExists): error when creating "kubernetes-dashboard.yaml": secrets "kubernetes-dashboard-certs" already exists
Error from server (AlreadyExists): error when creating "kubernetes-dashboard.yaml": serviceaccounts "kubernetes-dashboard" already exists
Error from server (AlreadyExists): error when creating "kubernetes-dashboard.yaml": roles.rbac.authorization.k8s.io "kubernetes-dashboard-minimal" already exists
Error from server (AlreadyExists): error when creating "kubernetes-dashboard.yaml": rolebindings.rbac.authorization.k8s.io "kubernetes-dashboard-minimal" already exists
Error from server (AlreadyExists): error when creating "kubernetes-dashboard.yaml": deployments.apps "kubernetes-dashboard" already exists
Error from server (AlreadyExists): error when creating "kubernetes-dashboard.yaml": services "kubernetes-dashboard" already exists

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5. 卸载之前安装的内容：

kubectl delete -f  kubernetes-dashboard.yaml

6. 重新安装dashboard：

kubectl create -f kubernetes-dashboard.yaml

7. 获取token：

kubectl -n kube-system describe $(kubectl -n kube-system get secret -n kube-system -o name | grep namespace) | grep token

8.如果谷歌浏览器访问不了，则用火狐访问：http://nodeIp:nodePort

查看服务被分配到哪个节点上：$ kubectl get pods -n kube-system -o wide

 

9. 访问以下链接时，将获取的token粘贴到输入框中：

 之后就可以通过令牌登录了。

解决证书问题：

# 定义别名
$ alias ksys='kubectl -n kube-system'

# 查看证书
$ ksys get secret

# 删除证书
$ ksys delete secret kubernetes-dashboard-certs

# 创建证书
$ openssl genrsa -out dashboard.key 2048

$ openssl req -new -out dashboard.csr -key dashboard.key -subj '/CN=192.168.182.139'

$ openssl x509 -req -in dashboard.csr -signkey dashboard.key -out dashboard.crt

$ openssl x509 -in dashboard.crt -text -noout

$ ksys create secret generic kubernetes-dashboard-certs --from-file=dashboard.key --from-file=dashboard.crt

~~~未完待续~~~