Initialize master and worker nodes

Initialization script init.sh

#!/bin/bash

# Execute on both master and worker nodes

# Install docker
# The reference documents are as follows
# https://docs.docker.com/install/linux/docker-ce/centos/ 
# https://docs.docker.com/install/linux/linux-postinstall/

# Uninstall old version
yum remove -y docker \
docker-client \
docker-client-latest \
docker-common \
docker-latest \
docker-latest-logrotate \
docker-logrotate \
docker-selinux \
docker-engine-selinux \
docker-engine

# Set up yum repository
yum install -y yum-utils \
device-mapper-persistent-data \
lvm2
yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

# Install and start docker
yum install -y docker-ce-18.09.7 docker-ce-cli-18.09.7 containerd.io
systemctl enable docker
systemctl start docker

# Install NFS utils
# nfs utils must be installed before nfs networked storage can be mounted
yum install -y nfs-utils

# Turn off firewall
systemctl stop firewalld
systemctl disable firewalld

# Turn off SeLinux
setenforce 0
sed -i "s/SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config

# Close swap
swapoff -a
yes | cp /etc/fstab /etc/fstab_bak
cat /etc/fstab_bak |grep -v swap > /etc/fstab

# Modify / etc/sysctl.conf
# If configured, modify
sed -i "s#^net.ipv4.ip_forward.*#net.ipv4.ip_forward=1#g"  /etc/sysctl.conf
sed -i "s#^net.bridge.bridge-nf-call-ip6tables.*#net.bridge.bridge-nf-call-ip6tables=1#g"  /etc/sysctl.conf
sed -i "s#^net.bridge.bridge-nf-call-iptables.*#net.bridge.bridge-nf-call-iptables=1#g"  /etc/sysctl.conf
# Maybe not, add
echo "net.ipv4.ip_forward = 1" >> /etc/sysctl.conf
echo "net.bridge.bridge-nf-call-ip6tables = 1" >> /etc/sysctl.conf
echo "net.bridge.bridge-nf-call-iptables = 1" >> /etc/sysctl.conf
# Execute command to apply
sysctl -p

# Configure the yum source of K8S
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

# Uninstall old version
yum remove -y kubelet kubeadm kubectl

# Install kubelet, kubeadm, kubectl
yum install -y kubelet-1.16.0 kubeadm-1.16.0 kubectl-1.16.0

# Modify docker Cgroup Driver to systemd
# # In the file / usr/lib/systemd/system/docker.service, execstart = / usr / bin / docked - H FD: / / -- containerd = / run / containerd / containerd.sock
# # Modify to execstart = / usr / bin / docked - H FD: / / -- contained = / run / contained / contained. Sock -- exec opt native. Cgroupdriver = SYSTEMd
# If you do not modify it, you may encounter the following errors when adding worker nodes
# [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/
sed -i "s#^ExecStart=/usr/bin/dockerd.*#ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock --exec-opt native.cgroupdriver=systemd#g" /usr/lib/systemd/system/docker.service

# Set up docker image to improve the download speed and stability of docker image
# If you visit https://hub.docker.io at a very stable speed, you can also skip this step
curl -sSL https://get.daocloud.io/daotools/set_mirror.sh | sh -s http://f1361db2.m.daocloud.io

# Restart docker and start kubelet
systemctl daemon-reload
systemctl restart docker
systemctl enable kubelet && systemctl start kubelet

docker version

Sealos

# Download sealos
wget https://github.com/fanux/sealos/releases/download/v2.0.7/sealos
# Add execution permission and move sealos to / usr/bin
chmod +x sealos && mv sealos /usr/bin

sealos options

--Master master server address list
 --Node node server address list
 --User server ssh user name
 --passwd server ssh user password
 --PKG URL offline package location can be placed in the local directory or an http server. sealos will wget to the installation target machine
 --Version kubernetes version

Initialize k8s HA cluster

sealos init --passwd YOUR_SERVER_PASSWD  
  --master 172.31.194.114  --master 172.31.194.116  --master 172.31.194.115 \
  --node 172.31.194.117 \
  --pkg-url https://sealyun.oss-cn-beijing.aliyuncs.com/37374d999dbadb788ef0461844a70151-1.16.0/kube1.16.0.tar.gz  \ 
  --version v1.16.0

After execution, the last line of the shell output is as follows, indicating that the cluster deployment is successful

2019-11-07 17:30:20 [INFO] [github.com/fanux/sealos/install/print.go:25] sealos install success.

Let's get the state of the node

[root@master01 ~]# kubectl get nodes
NAME       STATUS   ROLES    AGE   VERSION
master01   Ready    master   11h   v1.16.0
master02   Ready    master   11h   v1.16.0
master03   Ready    master   11h   v1.16.0
node01     Ready    <none>   11h   v1.16.0

# Get service
[root@master01 ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   17h

# By looking at the ipvs rules, we can see that requests sent to 10.96.0.1 are loaded to all master nodes.
[root@master01 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.96.0.1:443 rr
  -> 172.31.194.114:6443          Masq    1      3          0         
  -> 172.31.194.115:6443          Masq    1      2          0         
  -> 172.31.194.116:6443          Masq    1      0          0