Kubernetes集群搭建：基于Kubeadm

一，环境准备

    * K8S版本为15.1

    * Docker版本最高支持18.06.1

二，Docker环境构建及替换

    1，清除原Docker环境，原版本为最新版

yum remove docker 
                  docker-client 
                  docker-client-latest 
                  docker-common 
                  docker-latest 
                  docker-latest-logrotate 
                  docker-logrotate 
                  docker-selinux 
                  docker-engine-selinux 
                  docker-engine
 
rm -rf /etc/systemd/system/docker.service.d
 
rm -rf /var/lib/docker
 
rm -rf /var/run/docker

    2，如果清除后依旧包冲突错误

file /usr/share/man/man1/docker-manifest-annotate.1.gz from install of docker-ce-18.06.1.ce-3.el7.x86_64 conflicts with file from package docker-ce-cli-1:18.09.6-3.el7.x86_64

          通过yum命令手动移除冲突包

yum erase docker-common-2:1.12.6-68.gitec8512b.el7.centos.x86_64

    3，安装18.06.1版本Docker

yum install -y docker-ce-18.06.1.ce-3.el7

    4，其他Docker安装参考之前博客 Docker：环境搭建

三，Kubernetes集群环境搭建

    1，基础环境准备

        a，机器节点准备，虚拟机搭建，内存不够，host名称只支持[-.]两个特殊符号

        b，/etc/hosts文件设置

            * 添加命令

cat >> /etc/hosts << EOF
192.168.91.136 master
192.168.91.137 node1
192.168.91.138 node2
EOF

            * hosts文件配置如下

        c，配置时间同步，使用chrony同步时间，配置master节点与网络NTP服务器同步时间，所有node节点与master节点同步时间

              * 配置Master节点

// 安装chrony：
yum install -y chrony
// 注释默认ntp服务器
sed -i 's/^server/#&/' /etc/chrony.conf
// 指定上游公共 ntp 服务器，并允许其他节点同步时间
cat >> /etc/chrony.conf << EOF
server 0.asia.pool.ntp.org iburst
server 1.asia.pool.ntp.org iburst
server 2.asia.pool.ntp.org iburst
server 3.asia.pool.ntp.org iburst
allow all
EOF
// 重启chronyd服务并设为开机启动：
systemctl enable chronyd && systemctl restart chronyd
// 开启网络时间同步功能
timedatectl set-ntp true

              * 配置Node节点

// 安装chrony：
yum install -y chrony
// 注释默认服务器
sed -i 's/^server/#&/' /etc/chrony.conf
// 指定内网 master节点为上游NTP服务器
echo server 192.168.91.128 iburst >> /etc/chrony.conf
// 重启服务并设为开机启动：
systemctl enable chronyd && systemctl restart chronyd

              * 所有节点执行chronyc sources命令，查看存在以^*开头的行，说明已经与服务器时间同步

       d，设置网桥包经过iptalbes RHEL / CentOS 7上的一些用户报告了由于iptables被绕过而导致流量路由不正确的问题。创建/etc/sysctl.d/k8s.conf文件，添加如下内容

// 添加文件内容
cat <<EOF >  /etc/sysctl.d/k8s.conf
vm.swappiness = 0
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF
// 使配置生效
modprobe br_netfilter
sysctl -p /etc/sysctl.d/k8s.conf

        e，kube-proxy开启ipvs的前提条件 由于ipvs已经加入到了内核的主干，所以为kube-proxy开启ipvs的前提需要加载以下的内核模块： 在所有的Kubernetes节点执行以下脚本

// 添加内容
cat > /etc/sysconfig/modules/ipvs.modules <<EOF
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4
EOF

// 执行脚本
chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules && lsmod | grep -e ip_vs -e nf_conntrack_ipv4

         f，上面脚本创建了/etc/sysconfig/modules/ipvs.modules文件，保证在节点重启后能自动加载所需模块。 使用lsmod | grep -e ip_vs -e nf_conntrack_ipv4命令查看是否已经正确加载所需的内核模块。 接下来还需要确保各个节点上已经安装了ipset软件包。 为了便于查看ipvs的代理规则，最好安装一下管理工具ipvsadm。

yum install ipset ipvsadm -y

        g，安装kubeadm、kubelet、kubectl

// 配置kubernetes.repo的源，由于官方源国内无法访问，这里使用阿里云yum源
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

// 在所有节点上安装指定版本 kubelet、kubeadm 和 kubectl
// 此处直接下载版本为1.15.1
yum install -y kubelet kubeadm kubectl

// 启动kubelet服务
systemctl enable kubelet && systemctl start kubelet

    2，Master环境搭建

        a，安装废了后，重置节点

kubeadm reset

       b，初始化Master节点，注意对address和version进行更改，version与kubeadm等版本一致

kubeadm init 
    --apiserver-advertise-address=192.168.91.136 
    --image-repository registry.aliyuncs.com/google_containers 
    --kubernetes-version v1.15.1 
    --pod-network-cidr=10.244.0.0/16

           * 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。

           * image-repository：Kubenetes默认Registries地址是 k8s.gcr.io，在国内并不能访问 gcr.io，在1.15版本中我们可以增加–image-repository参数，默认值是 k8s.gcr.io，将其指定为阿里云镜像地址：registry.aliyuncs.com/google_containers。

           * kubernetes-version=v1.15.1：关闭版本探测，因为它的默认值是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（最新版：v1.13.1）来跳过网络请求。

        c，初始化过程，及说明

[root@master ~]# kubeadm init     --apiserver-advertise-address=192.168.91.136     --image-repository registry.aliyuncs.com/google_containers     --kubernetes-version v1.15.1     --pod-network-cidr=10.244.0.0/16
[init] Using Kubernetes version: v1.15.1
[preflight] Running pre-flight checks
        [WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Activating the kubelet service
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [master localhost] and IPs [192.168.91.136 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [master localhost] and IPs [192.168.91.136 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.91.136]
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[control-plane] Using manifest folder "/etc/kubernetes/manifests"
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[apiclient] All control plane components are healthy after 25.517374 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.15" in namespace kube-system with the configuration for the kubelets in the cluster
[upload-certs] Skipping phase. Please see --upload-certs
[mark-control-plane] Marking the node master as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: qozff5.j2weqyh2uhcz4l7f
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstrap-token] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy

Your Kubernetes control-plane has initialized successfully!

To start using your cluster, you need to run the following as a regular user:

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

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  https://kubernetes.io/docs/concepts/cluster-administration/addons/

Then you can join any number of worker nodes by running the following on each as root:

kubeadm join 192.168.91.136:6443 --token qozff5.j2weqyh2uhcz4l7f 
    --discovery-token-ca-cert-hash sha256:f427679e26a28dec67138e2806c4ec2c03827665dd1233b11e7f60cb3c260b60 

          * [preflight] kubeadm 执行初始化前的检查

          * [kubelet-start] 生成kubelet的配置文件”/var/lib/kubelet/config.yaml”

          * [certificates] 生成相关的各种token和证书

          * [certificates] 生成相关的各种token和证书
          * [kubeconfig] 生成 KubeConfig 文件，kubelet 需要这个文件与 Master 通信
          * [control-plane] 安装 Master 组件，会从指定的 Registry 下载组件的 Docker 镜像。
          * [bootstraptoken] 生成token记录下来，后边使用kubeadm join往集群中添加节点时会用到
          * [addons] 安装附加组件 kube-proxy 和 kube-dns。
          * Kubernetes Master 初始化成功，提示如何配置常规用户使用kubectl访问集群。
          * 提示如何安装 Pod 网络。
          * 提示如何注册其他节点到 Cluster。

          * join命令必须记住，后续需要使用join对应的token添加node节点

        d，配置 kubectl：kubectl 是管理 Kubernetes Cluster 的命令行工具，前面我们已经在所有的节点安装了 kubectl。Master 初始化完成后需要做一些配置工作，然后 kubectl 就能使用了。需要这些配置命令的原因是：Kubernetes 集群默认需要加密方式访问。所以，这几条命令，就是将刚刚部署生成的 Kubernetes 集群的安全配置文件，保存到当前用户的.kube 目录下，kubectl 默认会使用这个目录下的授权信息访问 Kubernetes 集群。 如果不这么做的话，我们每次都需要通过 export KUBECONFIG 环境变量告诉 kubectl 这个安全配置文件的位置。 配置完成后centos用户就可以使用 kubectl 命令管理集群了。(此演示直接在root账号运行)

// 追加sudo权限,并配置sudo免密
sed -i '/^root/acentos  ALL=(ALL)       NOPASSWD:ALL' /etc/sudoers

// 保存集群安全配置文件到当前用户.kube目录
mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config

// 启用 kubectl 命令自动补全功能（注销重新登录生效）
echo "source <(kubectl completion bash)" >> ~/.bashrc

        e，配置好Master节点后，查看集群状态，确定每一个组件都处于healthy状态

kubectl get cs

        f，确定组件都处于healthy状态后，查看节点状态

kubectl get nodes

        g，只有一个Master节点，且节点处于NotReady状态。使用 kubectl describe 命令来查看这个节点（Node）对象的详细信息、状态和事件（Event）

kubectl describe node master

        h，通过 kubectl describe 指令的输出，我们可以看到 NodeNotReady 的原因在于，我们尚未部署任何网络插件，kube-proxy等组件还处于starting状态。 另外，我们还可以通过 kubectl 检查这个节点上各个系统 Pod 的状态，其中，kube-system 是 Kubernetes 项目预留的系统 Pod 的工作空间（Namepsace，注意它并不是 Linux Namespace，它只是 Kubernetes 划分不同工作空间的单位），可以看到，CoreDNS依赖于网络的 Pod 都处于 Pending 状态，即调度失败。这当然是符合预期的：因为这个 Master 节点的网络尚未就绪

kubectl get pod -n kube-system -o wide

        i，部署网络插件 要让 Kubernetes Cluster 能够工作，必须安装 Pod 网络，否则 Pod 之间无法通信。 Kubernetes 支持多种网络方案，这里我们使用 flannel 执行如下命令部署 flannel： kubectl apply -f kube-flannel.yml

          * 上传 kube-flannel.yml 文件，文件内容如下

---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: flannel
rules:
  - 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",
      "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: extensions/v1beta1
kind: DaemonSet
metadata:
  name: kube-flannel-ds-amd64
  namespace: kube-system
  labels:
    tier: node
    app: flannel
spec:
  template:
    metadata:
      labels:
        tier: node
        app: flannel
    spec:
      hostNetwork: true
      nodeSelector:
        beta.kubernetes.io/arch: amd64
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: quay.io/coreos/flannel:v0.10.0-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:v0.10.0-amd64
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            cpu: "100m"
            memory: "50Mi"
          limits:
            cpu: "100m"
            memory: "50Mi"
        securityContext:
          privileged: true
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        volumeMounts:
        - name: run
          mountPath: /run
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      volumes:
        - name: run
          hostPath:
            path: /run
        - name: cni
          hostPath:
            path: /etc/cni/net.d
        - name: flannel-cfg
          configMap:
            name: kube-flannel-cfg
---
apiVersion: extensions/v1beta1
kind: DaemonSet
metadata:
  name: kube-flannel-ds-arm64
  namespace: kube-system
  labels:
    tier: node
    app: flannel
spec:
  template:
    metadata:
      labels:
        tier: node
        app: flannel
    spec:
      hostNetwork: true
      nodeSelector:
        beta.kubernetes.io/arch: arm64
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: quay.io/coreos/flannel:v0.10.0-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:v0.10.0-arm64
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            cpu: "100m"
            memory: "50Mi"
          limits:
            cpu: "100m"
            memory: "50Mi"
        securityContext:
          privileged: true
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        volumeMounts:
        - name: run
          mountPath: /run
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      volumes:
        - name: run
          hostPath:
            path: /run
        - name: cni
          hostPath:
            path: /etc/cni/net.d
        - name: flannel-cfg
          configMap:
            name: kube-flannel-cfg
---
apiVersion: extensions/v1beta1
kind: DaemonSet
metadata:
  name: kube-flannel-ds-arm
  namespace: kube-system
  labels:
    tier: node
    app: flannel
spec:
  template:
    metadata:
      labels:
        tier: node
        app: flannel
    spec:
      hostNetwork: true
      nodeSelector:
        beta.kubernetes.io/arch: arm
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: quay.io/coreos/flannel:v0.10.0-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:v0.10.0-arm
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            cpu: "100m"
            memory: "50Mi"
          limits:
            cpu: "100m"
            memory: "50Mi"
        securityContext:
          privileged: true
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        volumeMounts:
        - name: run
          mountPath: /run
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      volumes:
        - name: run
          hostPath:
            path: /run
        - name: cni
          hostPath:
            path: /etc/cni/net.d
        - name: flannel-cfg
          configMap:
            name: kube-flannel-cfg
---
apiVersion: extensions/v1beta1
kind: DaemonSet
metadata:
  name: kube-flannel-ds-ppc64le
  namespace: kube-system
  labels:
    tier: node
    app: flannel
spec:
  template:
    metadata:
      labels:
        tier: node
        app: flannel
    spec:
      hostNetwork: true
      nodeSelector:
        beta.kubernetes.io/arch: ppc64le
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: quay.io/coreos/flannel:v0.10.0-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:v0.10.0-ppc64le
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            cpu: "100m"
            memory: "50Mi"
          limits:
            cpu: "100m"
            memory: "50Mi"
        securityContext:
          privileged: true
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        volumeMounts:
        - name: run
          mountPath: /run
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      volumes:
        - name: run
          hostPath:
            path: /run
        - name: cni
          hostPath:
            path: /etc/cni/net.d
        - name: flannel-cfg
          configMap:
            name: kube-flannel-cfg
---
apiVersion: extensions/v1beta1
kind: DaemonSet
metadata:
  name: kube-flannel-ds-s390x
  namespace: kube-system
  labels:
    tier: node
    app: flannel
spec:
  template:
    metadata:
      labels:
        tier: node
        app: flannel
    spec:
      hostNetwork: true
      nodeSelector:
        beta.kubernetes.io/arch: s390x
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: quay.io/coreos/flannel:v0.10.0-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:v0.10.0-s390x
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            cpu: "100m"
            memory: "50Mi"
          limits:
            cpu: "100m"
            memory: "50Mi"
        securityContext:
          privileged: true
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        volumeMounts:
        - name: run
          mountPath: /run
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      volumes:
        - name: run
          hostPath:
            path: /run
        - name: cni
          hostPath:
            path: /etc/cni/net.d
        - name: flannel-cfg
          configMap:
            name: kube-flannel-cfg

          * 执行文件

kubectl apply -f kube-flannel.yml

        j，安装成功flannel网络插件后，重新查看POD状态。圈出来的部分，可能会存在短暂的init状态，稍等即可

            * pod状态为Pending、ContainerCreating、ImagePullBackOff 都表明 Pod 没有就绪，Running 才是就绪状态，如果pod状态异常，可以通过命令拉取异常信息

// kube-flannel-ds-amd64-d2r8p 表示pod名称
kubectl describe pod kube-flannel-ds-amd64-d2r8p --namespace=kube-system

        k，重新查看节点状态，节点状态从notReady转为ready，Master节点部署完成，在默认情况下，Kubernetes 的 Master 节点是不能运行用户 Pod 的。

    3，Worker环境搭建

         a，执行init时候提示的join语句，显示下列信息说明添加成功

kubeadm join 192.168.91.136:6443 --token qozff5.j2weqyh2uhcz4l7f 
    --discovery-token-ca-cert-hash sha256:f427679e26a28dec67138e2806c4ec2c03827665dd1233b11e7f60cb3c260b60 	

        b，如果忘了记住join信息，可以通过语句重新生成

kubeadm token create --print-join-command

        c，重复上一步添加node2节点，添加后，在master节点查看节点及pod。如果存在NotReady节点，可以稍等会，等pod全部启动，或者查看pod状态，对不是Running状态的pod进行具体分析！（pod状态为Pending、ContainerCreating、ImagePullBackOff 都表明 Pod 没有就绪）

        d，集群至此，全部搭建完成

四，集群验证

    1，首先验证kube-apiserver, kube-controller-manager, kube-scheduler, pod network 是否正常： 部署一个 Nginx Deployment，包含2个Pod 

        a，创建

// 创建deployment nginx
[root@master admin]# kubectl create deployment nginx --image=nginx:alpine
deployment.apps/nginx created
// 设置为两个副本
[root@master admin]#  kubectl scale deployment nginx --replicas=2
deployment.extensions/nginx scaled

        b，查看

[root@master admin]#  kubectl get pods -l app=nginx -o wide

    2，再验证一下kube-proxy是否正常：以 NodePort 方式对外提供服务

// 以NodePort运行，并开放80端口
[root@master admin]# kubectl expose deployment nginx --port=80 --type=NodePort
service/nginx exposed
// 查看详情
[root@master admin]# kubectl get services nginx
NAME    TYPE       CLUSTER-IP    EXTERNAL-IP   PORT(S)        AGE
nginx   NodePort   10.98.47.23   <none>        80:30018/TCP   5s

最后

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