配置hosts

vim /etc/hosts

追加如下内容

192.168.18.10 k8s-master
192.168.18.11 k8s-node1
192.168.18.12 k8s-node2
192.168.18.13 k8s-admin

安装依赖包

yum install -y conntrack ntpdate ntp ipvsadm ipset jq iptables curl sysstat libseccomp wget vimnet-tools git

配置防火墙

设置防火墙为 Iptables 并设置空规则

systemctl stop firewalld && systemctl disable firewalld
yum -y install iptables-services && systemctl start iptables && systemctl enable iptables && iptables -F && service iptables save

关闭selinux

使用命令永久关闭selinux

sed -i 's/enforcing/disabled/' /etc/selinux/config && setenforce 0

关闭swap分区

两条命令都需要执行

# 临时关闭
swapoff -a

# 永久关闭，下次生效
sed -ri 's/.*swap.*/#&/' /etc/fstab

调整内核参数

cat > kubernetes.conf << EOF
net.bridge.bridge-nf-call-iptables=1
net.bridge.bridge-nf-call-ip6tables=1
net.ipv4.ip_forward=1
net.ipv4.tcp_tw_recycle=0
vm.swappiness=0 # 禁止使用 swap 空间，只有当系统 OOM 时才允许使用它
vm.overcommit_memory=1 # 不检查物理内存是否够用
vm.panic_on_oom=0 # 开启 OOM
fs.inotify.max_user_instances=8192
fs.inotify.max_user_watches=1048576
fs.file-max=52706963
fs.nr_open=52706963
net.ipv6.conf.all.disable_ipv6=1
net.netfilter.nf_conntrack_max=2310720
EOF


cp kubernetes.conf /etc/sysctl.d/kubernetes.conf
sysctl -p /etc/sysctl.d/kubernetes.conf

调整系统时区

rm -f /etc/localtime
ln -sf /usr/share/zoneinfo/Asia/Shanghai
reboot

关闭系统不需要服务

systemctl stop postfix && systemctl disable postfix

设置 rsyslogd 和 systemd journald

mkdir /var/log/journal # 持久化保存日志的目录
mkdir /etc/systemd/journald.conf.d
cat > /etc/systemd/journald.conf.d/99-prophet.conf << EOF
[Journal]
Storage=persistent
Compress=yes
SyncIntervalSec=5m
RateLimitInterval=30s
RateLimitBurst=1000
SystemMaxUse=10G
SystemMaxFileSize=200M
MaxRetentionSec=2week
ForwardToSyslog=no
EOF
systemctl restart systemd-journald

升级系统内核

CentOS 7.x 系统自带的 3.10.x 内核存在一些 Bugs，导致运行的 Docker、Kubernetes 不稳定。

rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm

安装完成后检查 /boot/grub2/grub.cfg 中对应内核 menuentry 中是否包含initrd16配置，如果没有，再安装一次！

cat /boot/grub2/grub.cfg | grep initrd16
yum --enablerepo=elrepo-kernel install -y kernel-lt

设置开机从新内核启动

grub2-set-default 'CentOS Linux (4.4.189-1.el7.elrepo.x86_64) 7 (Core)'

检查一下

reboot
uname -r 

设置主机名

hostnamectl set-hostname k8s-master

加载ip_vs内核模块

modprobe ip_vs
modprobe ip_vs_rr
modprobe ip_vs_wrr
modprobe ip_vs_sh
modprobe nf_conntrack_ipv4

设置下次开机自动加载

cat > /etc/modules-load.d/ip_vs.conf << EOF 
ip_vs
ip_vs_rr
ip_vs_wrr
ip_vs_sh
nf_conntrack_ipv4
EOF

安装kubeadm,kubelet和kubectl

配置yum源(这里使用阿里云的源)

cat > /etc/yum.repos.d/kubernetes.repo << EOF
[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

安装指定版本的kubeadm,kubelet,kubectl

yum install -y kubelet-1.18.8 kubeadm-1.18.8 kubectl-1.18.8

设置开机自启

systemctl enable kubelet

列出所有版本

yum list kubelet --showduplicates

部署Kubernetes Master节点

master节点初始化

kubeadm init \
  --kubernetes-version 1.18.8 \
  --apiserver-advertise-address=0.0.0.0 \
  --service-cidr=10.96.0.0/16 \
  --pod-network-cidr=10.245.0.0/16 \
  --image-repository registry.aliyuncs.com/google_containers 

参数说明

• –kubernetes-version v1.18.8 指定版本
• –apiserver-advertise-address 为通告给其它组件的IP，一般应为master节点的IP地址
• –service-cidr 指定service网络，不能和node网络冲突
• –pod-network-cidr 指定pod网络，不能和node网络、service网络冲突
• –image-repository registry.aliyuncs.com/google_containers 指定镜像源，由于默认拉取镜像地址k8s.gcr.io国内无法访问，这里指定阿里云镜像仓库地址。
• 如果k8s版本比较新，可能阿里云没有对应的镜像，就需要自己从其它地方获取镜像了。
• –control-plane-endpoint 标志应该被设置成负载均衡器的地址或 DNS 和端口(可选)

注意点：版本必须和上边安装的kubelet,kubead,kubectl保持一致

配置kubectl

就是执行初始化成功后输出的那三条命令

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

查看节点信息

kubectl get nodes

此时只能看到master节点，等待其他节点加入进来后即可看到。

安装 flannel

创建配置文件

vim kube-flannel.yml

填写如下内容（推荐写在一个yaml文件中然后上传）

---
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": "10.245.0.0/16",
      "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.io/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.io/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

执行yaml文件

kubectl apply -f kube-flannel.yaml

查看flannel部署结果

kubectl -n kube-system get pods -o wide

查看各个node的状态

kubectl get nodes