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"