kubernets集群安装

1.软件及硬件参数

操作系统
CentOS Linux release 7.6.1810 (Core)

三台机器
192.168.223.140 2G 2C
192.168.223.142 2G 2C
192.168.223.143 2G 2C

2.环境初始化

修改hostname

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配置hosts文件

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重启所有机器
确保各台机器之间通过hostname相互ping通

时间同步
kubernetes要求集群中的节点时间必须精确一致，这里使用chronyd服务从网络同步时间

#启动chronyd服务
systemctl start chronyd
#设置chronyd开机启动
systemctl enable chronyd
#查看时间
date

禁止iptables和firewalld服务
kubernetes和docker在运行中会产生大量的iptables规则，为了不让系统规则跟它们混淆，这里关闭规则

#关闭firewalld服务
systemctl stop firewalld
systemctl disable firewalld
#关闭iptables服务
systemctl stop iptables
systemctl disable iptables

禁用selinux
selinux是linux系统下的一个安全服务，如果不关闭它，在安装的过程中会出现各种问题

vim /etc/selinux/config
#修改
SELINUX=disabled

禁用swap分区

vim /etc/fstab
#禁用最后一行
#/dev/mapper/centos-swap swap

修改内核参数

vim /etc/sysctl.d/kubernetes.conf
#写入配置
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
#生效
sysctl -p
#网桥过滤
modprobe br_netfilter
#查看网桥过滤是否加载成功
lsmod | grep br_netfilter

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配置ipvs

#安装ipset和ipvsadm
yum install ipset ipvsadmin -y
#添加需要加载的模块写入脚本文件
cat <  /etc/sysconfig/modules/ipvs.modules
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4
EOF
#为脚本文件添加执行权限
chmod +x /etc/sysconfig/modules/ipvs.modules
#执行脚本文件
/bin/bash /etc/sysconfig/modules/ipvs.modules
#查看对应的模块是否加载成功
lsmod | grep -e ip_vs -e nf_conntrack_ipv4

重启三台机器
验证selinux和swap是否生效

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3.安装Docker

切换镜像源

wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo

查看当前镜像源中支持的docker版本

yum list docker-ce --showduplicates

安装特定版本的docker-ce

yum install --setopt=obsoletes=0 docker-ce-18.06.3.ce-3.el7 -y

配置docker镜像地址

#创建文件夹
mkdir /etc/docker
#写入内容
cat <  /etc/docker/daemon.json
{
  "exec-opts": ["native.cgroupdriver=systemd"],
  "registry-mirrors": ["https://kn0t2bca.mirror.aliyuncs.com"]
}

启动docker

systemctl restart docker
systemctl enable docker

4.安装kubernetes组件

配置kubernetes镜像源

vim /etc/yum.repos.d/kubernetes.repo
#写入内容
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
       http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg

安装kubeadm、kubelet和kubectl

yum install --setopt=obsoletes=0 kubeadm-1.17.4-0 kubelet-1.17.4-0 kubectl-1.17.4-0 -y

配置kubelet的cgroup

vim /etc/sysconfig/kubelet
#写入
KUBELET_CGROUP_ARGS="--cgroup-driver=systemd"
KUBE_PROXY_MODE="ipvs"

设置kubelet开机自启

systemctl enable kubelet

5.集群镜像安装

下载镜像

#定义
images=(
    kube-apiserver:v1.17.4
    kube-controller-manager:v1.17.4
    kube-scheduler:v1.17.4
    kube-proxy:v1.17.4
    pause:3.1
    etcd:3.4.3-0
    coredns:1.6.5
)
#下载
for imageName in ${images[@]} ; do
    docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
    docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName       k8s.gcr.io/$imageName
    docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
done

创建集群

kubeadm init \
    --kubernetes-version=v1.17.4 \
    --pod-network-cidr=10.244.0.0/16 \
    --service-cidr=10.96.0.0/12 \
    --apiserver-advertise-address=192.168.223.140

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创建必要文件

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

将node节点加入集群
注意：只在node节点上执行

kubeadm join 192.168.223.140:6443 --token dszcma.zl1wdijx73bxvgh0 \
>     --discovery-token-ca-cert-hash sha256:6c2724319d2ac01c06256fe85354430f6dc1489116c57c3bd6b81ea355204373

查看集群节点

kubectl get nodes

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6.安装网络插件

获取fannel的配置文件

wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

下载之后，修改文件中quay.io仓库为quay-mirror.qiniu.com
如果无法下载，请复制下面的内容保存为 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', 'NET_RAW']
  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/v1
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/v1
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
  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: kubernetes.io/os
                operator: In
                values:
                - linux
      hostNetwork: true
      priorityClassName: system-node-critical
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: quay-mirror.qiniu.com/coreos/flannel:v0.14.0
        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-mirror.qiniu.com/coreos/flannel:v0.14.0
        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", "NET_RAW"]
        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

使用配置文件启动fannel

kubectl apply -f kube-flannel.yml

再次查看集群节点的状态
耐心等待一会，有时候会比较慢

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集群中所有节点的状态都为Ready，至此kubernetes的集群环境搭建完成。

6.服务部署

部署nginx

#在master节点执行
kubectl create deployment nginx --image=nginx:1.14-alpine

暴露端口

kubectl expose deployment nginx --port=80 --type=NodePort

查看服务状态

kubectl get pods,service

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访问nginx

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