环境准备

设置系统主机名以及Host文件的相互解析

[root@localhost ~]# hostnamectl  set-hostname  k8s-master01 #k8s-master01
[root@localhost ~]# hostnamectl  set-hostname  k8s-node01 #k8s-node01
[root@localhost ~]# hostnamectl  set-hostname  k8s-node02 # k8s-node02
[root@k8s-master01 ~]# vi /etc/hosts 
10.0.2.14 k8s-master01
10.0.2.15 k8s-node01
10.0.2.16 k8s-node02

安装依赖包

[root@k8s-master01 ~]# yum install -y conntrack ntpdate ntp ipvsadm ipset jq iptables curl sysstat libseccomp wgetvimnet-tools git

设置防火墙为 Iptables 并设置空规则

[root@k8s-master01 ~]# yum -y install iptables-services  &&  systemctl  start iptables  &&  systemctl  enable iptables&&  iptables -F  &&  service iptables save

永久关闭虚拟内存

[root@k8s-master01 ~]# swapoff -a && sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab # k8s-node01、 # k8s-node02同步，kubeadmin安装k8s的时候初始化会检测swap分区有没有关闭，容器POD可能会放到swap运行，大大降低工作效率

针对k8s调整内核参数

[root@k8s-master01 ~]# 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 
> vm.overcommit_memory=1 
> vm.panic_on_oom=0 
> 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

[root@k8s-master01 ~]# cp kubernetes.conf  /etc/sysctl.d/kubernetes.conf 
[root@k8s-master01 ~]# sysctl -p /etc/sysctl.d/kubernetes.conf  
关闭系统不需要服务
[root@k8s-master01 ~]# systemctl stop postfix && systemctl disable postfix #尽可能降低系统占用空间

设置 rsyslogd 和 systemd journald

[root@k8s-master01 ~]#mkdir /var/log/journal # 持久化保存日志的目录
[root@k8s-master01 ~]#mkdir /etc/systemd/journald.conf.d
[root@k8s-master01 ~]#cat > /etc/systemd/journald.conf.d/99-prophet.conf <<EOF
[Journal]
# 持久化保存到磁盘
Storage=persistent
# 压缩历史日志Compress=yes

SyncIntervalSec=5m
RateLimitInterval=30s
RateLimitBurst=1000

# 最大占用空间 10G
SystemMaxUse=10G

# 单日志文件最大 200M
SystemMaxFileSize=200M

# 日志保存时间 2 周
MaxRetentionSec=2week

# 不将日志转发到 
syslogForwardToSyslog=noEOF
EOF

[root@k8s-master01 ~]# systemctl restart systemd-journald

升级系统内核为 4.44版本

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

[root@k8s-master01 ~]# 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！
[root@k8s-master01 ~]# yum --enablerepo=elrepo-kernel install -y kernel-lt
设置开机从新内核启动
[root@k8s-master01 ~]# grub2-set-default 'CentOS Linux (4.4.234-1.el7.elrepo.x86_64) 7 (Core)'

开启kube-proxy开启ipvs的前置条件

主要解决svc与pod之间的调度关系，增加访问效率

[root@k8s-master01 ~]# modprobe br_netfilter #加载netfilter模块
[root@k8s-master01 ~]# 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
[root@k8s-master01 ~]# chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules &&lsmod | grep -e ip_vs -e nf_conntrack_ipv4

安装 Docker 软件

[root@k8s-master01 ~]# yum install -y yum-utils device-mapper-persistent-data lvm2
[root@k8s-master01 ~]# yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo
[root@k8s-master01 ~]# yum update -y && yum install -y docker-ce
[root@k8s-master01 ~]# mkdir /etc/docker #创建 /etc/docker 目录
[root@k8s-master01 ~]# cat > /etc/docker/daemon.json <<EOF
{
   "exec-opts": ["native.cgroupdriver=systemd"],
   "log-driver": "json-file",
   "log-opts": {
     "max-size": "100m" 
   }
}
EOF
[root@k8s-master01 ~]# mkdir -p /etc/systemd/system/docker.service.d
[root@k8s-master01 ~]# systemctl daemon-reload && systemctl restart docker && systemctl enable docker #重启docker服务

安装 Kubeadm （主从配置）

[root@k8s-master01 ~]# cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[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
EOF

[root@k8s-master01 ~]# yum -y install kubeadm-1.15.1 kubectl-1.15.1 kubelet-1.15.1
[root@k8s-master01 ~]# systemctl enable kubelet.service

初始化主节点

k8s-master01 上传 kubeadm-basic.images.tar.gzk8s-master01 上传 kubeadm-basic.images.tar.gz

[root@k8s-master01 ~]# tar -zxvf kubeadm-basic.images.tar.gz 
[root@k8s-master01 ~]# vi load-images.sh
#!/bin/bash

ls /root/kubeadm-basic.images > /tmp/image-list.txt
cd /root/kubeadm-basic.images

for i in $( cat /tmp/image-list.txt)
do 
        docker load -i $i
done

rm -rf /tmp/image-list.txt

[root@k8s-master01 ~]# chmod a+x load-images.sh 
[root@k8s-master01 ~]# ./load-images.sh
[root@k8s-master01 ~]# scp -r kubeadm-basic.images load-images.sh root@k8s-node01:/root
[root@k8s-master01 ~]# scp -r kubeadm-basic.images load-images.sh root@k8s-node02:/root #同样在node01、02上导入

[root@k8s-master01 ~]# kubeadm config print init-defaults > kubeadm-config.yaml #打印init默认的初始化文件
[root@k8s-master01 ~]# kubeadm-config.yaml
apiVersion: kubeadm.k8s.io/v1beta2
bootstrapTokens:
- groups:
  - system:bootstrappers:kubeadm:default-node-token
  token: abcdef.0123456789abcdef
  ttl: 24h0m0s
  usages:
  - signing
  - authentication
kind: InitConfiguration
localAPIEndpoint:
  advertiseAddress: 10.0.2.14
  bindPort: 6443
nodeRegistration:
  criSocket: /var/run/dockershim.sock
  name: k8s-node02
  taints:
  - effect: NoSchedule
    key: node-role.kubernetes.io/master
---
apiServer:
  timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns:
  type: CoreDNS
etcd:
  local:
    dataDir: /var/lib/etcd
imageRepository: k8s.gcr.io
kind: ClusterConfiguration
kubernetesVersion: v1.15.1 #截止目前已经到v1.18版本
networking:
  dnsDomain: cluster.local
  podSubnet: "10.244.0.0/16" #默认情况下，会安装一个Flannel的网络插件去实现覆盖线网络
  serviceSubnet: 10.96.0.0/12 
scheduler: {}

---     
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
featureGates:
  SupportIPVSProxyMode: true
mode: ipvs #把默认的调度模式改为ipvs模式

[root@k8s-master01 ~]# kubeadm init --config=kubeadm-config.yaml --experimental-upload-certs | tee kubeadm-init.log #指定从yaml文件进行初始化安装以及自动颁发证书，在高可用节点的时候比较有意义，在v1.13以后才支持
Flag --experimental-upload-certs has been deprecated, use --upload-certs instead
[init] Using Kubernetes version: v1.15.1
[preflight] Running pre-flight checks
        [WARNING SystemVerification]: this Docker version is not on the list of validated versions: 19.03.12. Latest validated version: 18.09
error execution phase preflight: [preflight] Some fatal errors occurred:
        [ERROR FileContent--proc-sys-net-bridge-bridge-nf-call-iptables]: /proc/sys/net/bridge/bridge-nf-call-iptables contents are not set to 1
采坑，Latest validated version: 18.09 

[root@k8s-master01 ~]# yum-config-manager --add-repo https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo #安装阿里的docker-ce仓库
[root@k8s-master01 ~]# yum list docker-ce --showduplicates|sort -r #查看可选择的docker-ce版本
[root@k8s-master01 ~]# yum -y install docker-ce-18.06.3.ce  #安装指定版本docker，重新导入即可

Your Kubernetes control-plane has initialized successfully!

[root@k8s-master01 ~]# mkdir -p $HOME/.kube
[root@k8s-master01 ~]# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
[root@k8s-master01 ~]# sudo chown $(id -u):$(id -g) $HOME/.kube/config

[root@k8s-master01 ~]# kubectl get node # 查询当前节点
NAME         STATUS     ROLES    AGE     VERSION
k8s-master01   NotReady   master   4m31s   v1.15.1 #NotReady状态，k8s要求有一个扁平化网络的存在，因为现在还没有构建Flannel

部署Flannel网络
[root@k8s-master01 ~]# mv kubeadm-init.log kubeadm-config.yaml install-k8s/
[root@k8s-master01 ~]# cd install-k8s/
[root@k8s-master01 install-k8s]# mkdir core
[root@k8s-master01 install-k8s]# mv * core/
[root@k8s-master01 install-k8s]# ls
[root@k8s-master01 install-k8s]# cd plugin/
[root@k8s-master01 plugin]# mkdir flannel
[root@k8s-master01 plugin]# cd flannel/
[root@k8s-master01 flannel]# wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
[root@k8s-master01 flannel]# kubectl create -f kube-flannel.yml #这样可以根据flannel资源清单
[root@k8s-master01 flannel]# kubectl get pod -n kube-system #所有的系统组件都会放在默认的kube-system命名空间下
NAME                                 READY   STATUS    RESTARTS   AGE
coredns-5c98db65d4-cf52v             1/1     Running   0          12m
coredns-5c98db65d4-qksxk             1/1     Running   0          12m
etcd-k8s-node02                      1/1     Running   0          11m
kube-apiserver-k8s-node02            1/1     Running   0          11m
kube-controller-manager-k8s-node02   1/1     Running   0          11m
kube-flannel-ds-amd64-zmspp          1/1     Running   0          72s 
kube-proxy-4xcjb                     1/1     Running   0          12m
kube-scheduler-k8s-node02            1/1     Running   0          11m
[root@k8s-master01 flannel]# kubectl get node
NAME         STATUS   ROLES    AGE   VERSION
k8s-master01   Ready    master   11m   v1.15.1 

[root@k8s-node01 ~]# kubeadm join 10.0.2.14:6443 --token abcdef.0123456789abcdef \
    --discovery-token-ca-cert-hash sha256:8c265e46d9aa3a04d7b837d3d5cec749e050bf7322cf7586ea22ff6bd9554fe5 #通过master节点输出信息在节点node01、node02上完成节点的加入

[root@k8s-master01 ~]# kubectl get node
NAME           STATUS   ROLES    AGE    VERSION
k8s-master01   Ready    master   11m    v1.15.1
k8s-node01     Ready    <none>   119s   v1.15.1
k8s-node02     Ready    <none>   97s    v1.15.1