Kubernetes概述
使用kubeadm快速部署一个k8s集群
Kubernetes高可用集群二进制部署（一）主机准备和负载均衡器安装
Kubernetes高可用集群二进制部署（二）ETCD集群部署
Kubernetes高可用集群二进制部署（三）部署api-server
Kubernetes高可用集群二进制部署（四）部署kubectl和kube-controller-manager、kube-scheduler
Kubernetes高可用集群二进制部署（五）kubelet、kube-proxy、Calico、CoreDNS
Kubernetes高可用集群二进制部署（六）Kubernetes集群节点添加

Kubernetes（简称为：k8s）是Google在2014年6月开源的一个容器集群管理系统，使用Go语言开发，用于管理云平台中多个主机上的容器化的应用，Kubernetes的目标是让部署容器化的应用简单并且高效,Kubernetes提供了资源调度、部署管理、服务发现、扩容缩容、监控，维护等一整套功能，努力成为跨主机集群的自动部署、扩展以及运行应用程序容器的平台。 它支持一系列容器工具, 包括Docker、Containerd等。

一、集群环境准备

1.1 主机规划

主机IP地址	主机名	主机配置	主机角色	软件列表
192.168.10.103	k8s-master1	2C4G	master + worker	kube-apiserver、kube-controller-manager、kube-scheduler、etcd、kubelet、kube-proxy、docker-ce
192.168.10.104	k8s-master2	2C4G	master + worker	kube-apiserver、kube-controller-manager、kube-scheduler、etcd、kubelet、kube-proxy、docker-ce
192.168.10.105	k8s-master3	2C4G	master + worker	kube-apiserver、kube-controller-manager、kube-scheduler、etcd、kubelet、kube-proxy、docker-ce
192.168.10.106	k8s-worker1	2C4G	worker1	kubelet、kube-proxy、docker-ce
192.168.10.107	k8s-worker2	2C4G	worker2(备用工作节点，集群搭建完成后作为新节点加入)	kubelet、kube-proxy、docker-ce
192.168.10.101	ha1	1C2G	LB	haproxy、keepalived
192.168.10.102	ha2	1C2G	LB	haproxy、keepalived
192.168.10.100	/	/	VIP(虚拟IP)

1.2 软件版本

软件名称	版本	备注
CentOS7	kernel版本：5.16
kubernetes	v1.21.10
etcd	v3.5.2	最新版本
calico	v3.19.4	网络插件
coredns	v1.8.4
docker-ce	20.10.13	YUM源默认
haproxy	5.18	YUM源默认
keepalived	3.5	YUM源默认

1.3 网络分配

网络名称	网段	备注
Node网络	192.168.10.101/107	集群节点网络
Service网络	10.96.0.0/16	实现服务发现时所使用的网络
Pod网络	10.244.0.0/16

二、集群部署

2.1主机准备

2.1.1 主机名设置

hostnamectl set-hostname xxx

关于主机名参见1.1小节主机规划表

2.1.2 主机与IP地址解析

cat >> /etc/hosts << EOF
192.168.10.101 ha1
192.168.10.102 ha2
192.168.10.103 k8s-master1
192.168.10.104 k8s-master2
192.168.10.105 k8s-master3
192.168.10.106 k8s-worker1
EOF

2.1.3 主机安全设置

2.1.3.1 关闭防火墙

systemctl stop firewalld
systemctl disable firewalld
firewall-cmd --state

2.1.3.2 关闭selinux

setenforce 0
sed -ri 's/SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config
sestatus

2.1.4 交换分区设置

swapoff -a
sed -ri 's/.*swap.*/#&/' /etc/fstab
echo "vm.swappiness=0" >> /etc/sysctl.conf
sysctl -p

2.1.5 主机系统时间同步

安装软件
yum -y install ntpdate

制定时间同步计划任务
crontab -e
0 */1 * * * ntpdate time1.aliyun.com

2.1.6 主机系统优化

limit优化

ulimit -SHn 65535

cat <<EOF >> /etc/security/limits.conf
* soft nofile 655360
* hard nofile 131072
* soft nproc 655350
* hard nproc 655350
* soft memlock unlimited
* hard memlock unlimited
EOF

2.1.7 ipvs管理工具安装及模块加载

为集群节点安装，负载均衡节点不用安装

yum -y install ipvsadm ipset sysstat conntrack libseccomp

所有节点配置ipvs模块，在内核4.19+版本nf_conntrack_ipv4已经改为nf_conntrack， 4.18以下使用nf_conntrack_ipv4即可： 
 
modprobe -- ip_vs 
modprobe -- ip_vs_rr 
modprobe -- ip_vs_wrr 
modprobe -- ip_vs_sh 
modprobe -- nf_conntrack 

创建 /etc/modules-load.d/ipvs.conf 并加入以下内容： 
cat >/etc/modules-load.d/ipvs.conf <<EOF 
ip_vs 
ip_vs_lc 
ip_vs_wlc 
ip_vs_rr 
ip_vs_wrr 
ip_vs_lblc 
ip_vs_lblcr 
ip_vs_dh 
ip_vs_sh 
ip_vs_fo 
ip_vs_nq 
ip_vs_sed 
ip_vs_ftp 
ip_vs_sh 
nf_conntrack 
ip_tables 
ip_set 
xt_set 
ipt_set 
ipt_rpfilter 
ipt_REJECT 
ipip 
EOF

设置为开机启动
systemctl enable --now systemd-modules-load.service

如果执行开机启动失败了，提示如下信息：

Job for systemd-modules-load.service failed because the control process exited with error code. See "systemctl status systemd-modules-load.service" and "journalctl -xe" for details.

Failed to find module 'ip_vs_fo'

具体原因是内核版本问题，不过也可以将文件中的ip_vs_fo 去掉，然后继续执行

2.1.8 Linux内核升级

在所有节点中安装,需要重新操作系统更换内核。

[root@localhost ~]# yum -y install perl

[root@localhost ~]# rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org

[root@localhost ~]# yum -y install https://www.elrepo.org/elrepo-release-7.0-4.el7.elrepo.noarch.rpm

[root@localhost ~]# yum  --enablerepo="elrepo-kernel"  -y install kernel-ml.x86_64

[root@localhost ~]# grub2-set-default 0

[root@localhost ~]# grub2-mkconfig -o /boot/grub2/grub.cfg

2.1.9 Linux内核优化

cat <<EOF > /etc/sysctl.d/k8s.conf
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-iptables = 1
net.bridge.bridge-nf-call-ip6tables = 1
fs.may_detach_mounts = 1
vm.overcommit_memory=1
vm.panic_on_oom=0
fs.inotify.max_user_watches=89100
fs.file-max=52706963
fs.nr_open=52706963
net.netfilter.nf_conntrack_max=2310720

net.ipv4.tcp_keepalive_time = 600
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.tcp_keepalive_intvl =15
net.ipv4.tcp_max_tw_buckets = 36000
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_max_orphans = 327680
net.ipv4.tcp_orphan_retries = 3
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_max_syn_backlog = 16384
net.ipv4.ip_conntrack_max = 131072
net.ipv4.tcp_max_syn_backlog = 16384
net.ipv4.tcp_timestamps = 0
net.core.somaxconn = 16384
EOF

sysctl --system

所有节点配置完内核后，重启服务器，保证重启后内核依旧加载
reboot -h now

重启后查看结果：
lsmod | grep --color=auto -e ip_vs -e nf_conntrack

2.1.10 其它工具安装(选装)

yum install wget jq psmisc vim net-tools telnet yum-utils device-mapper-persistent-data lvm2 git lrzsz -y

2.2 负载均衡器准备

2.2.1 安装haproxy与keepalived

在负载均衡两台服务器上安装

yum -y install haproxy keepalived

2.2.2 HAProxy配置

cat >/etc/haproxy/haproxy.cfg<<"EOF"
global
 maxconn 2000
 ulimit-n 16384
 log 127.0.0.1 local0 err
 stats timeout 30s

defaults
 log global
 mode http
 option httplog
 timeout connect 5000
 timeout client 50000
 timeout server 50000
 timeout http-request 15s
 timeout http-keep-alive 15s

frontend monitor-in
 bind *:33305
 mode http
 option httplog
 monitor-uri /monitor

frontend k8s-master
 bind 0.0.0.0:6443
 bind 127.0.0.1:6443
 mode tcp
 option tcplog
 tcp-request inspect-delay 5s
 default_backend k8s-master

backend k8s-master
 mode tcp
 option tcplog
 option tcp-check
 balance roundrobin #负载均衡策略
 default-server inter 10s downinter 5s rise 2 fall 2 slowstart 60s maxconn 250 maxqueue 256 weight 100
 server  k8s-master1  192.168.10.103:6443 check
 server  k8s-master2  192.168.10.104:6443 check
 server  k8s-master3  192.168.10.105:6443 check
EOF

2.2.3 KeepAlived

主从配置不一致，需要注意。

KeepAlived主要是对haproxy进行监控

ha1:

cat >/etc/keepalived/keepalived.conf<<"EOF"
! Configuration File for keepalived
global_defs {
   router_id LVS_DEVEL
script_user root
   enable_script_security
}
vrrp_script chk_apiserver {
   script "/etc/keepalived/check_apiserver.sh"
   interval 5
   weight -5
   fall 2 
rise 1
}
vrrp_instance VI_1 {
   state MASTER #指定主节点
   interface eth0 #网卡
   mcast_src_ip 192.168.10.101 #本机ip
   virtual_router_id 51
   priority 100 #优先级
   advert_int 2
   authentication {
       auth_type PASS
       auth_pass K8SHA_KA_AUTH
   }
   virtual_ipaddress {
       192.168.10.100 #虚拟ip 主节点和备份节点一样的
   }
   track_script {
      chk_apiserver #通过脚本实现监控
   }
}
EOF

ha2:

cat >/etc/keepalived/keepalived.conf<<"EOF"
! Configuration File for keepalived
global_defs {
   router_id LVS_DEVEL
script_user root
   enable_script_security
}
vrrp_script chk_apiserver {
   script "/etc/keepalived/check_apiserver.sh"
  interval 5
   weight -5
   fall 2 
rise 1
}
vrrp_instance VI_1 {
   state BACKUP
   interface eth0
   mcast_src_ip 192.168.10.102
   virtual_router_id 51
   priority 99
   advert_int 2
   authentication {
       auth_type PASS
       auth_pass K8SHA_KA_AUTH
   }
   virtual_ipaddress {
       192.168.10.100
   }
   track_script {
      chk_apiserver
   }
}
EOF

2.2.4 健康检查脚本

ha1及ha2均要配置（相同）

cat > /etc/keepalived/check_apiserver.sh <<"EOF"
#!/bin/bash
err=0 #定义变量
for k in $(seq 1 3)
do
   check_code=$(pgrep haproxy) #检查haproxy进程
   if [[ $check_code == "" ]]; then
       err=$(expr $err + 1)
       sleep 1
       continue
   else
       err=0
       break
   fi
done

if [[ $err != "0" ]]; then
   echo "systemctl stop keepalived"
   /usr/bin/systemctl stop keepalived
   exit 1
else
   exit 0
fi
EOF

chmod +x /etc/keepalived/check_apiserver.sh

2.2.5 启动服务并验证

systemctl daemon-reload
systemctl enable --now haproxy
systemctl enable --now keepalived

ip address show

ss -anput | grep ":6443"

http://192.168.10.101:33305/monitor