1.本节架构

2.安装nginx和keepalived

以下部署在hdss7-11.host.com及hdss7-12.host.com

yum install nginx keepalived -y

3.配置Nginx

cat >> /etc/nginx/nginx.conf <<‘eof‘
stream {
    upstream kube-apiserver {
        server 10.4.7.21:6443     max_fails=3 fail_timeout=30s;
        server 10.4.7.22:6443     max_fails=3 fail_timeout=30s;
    }
    server {
        listen 7443;
        proxy_connect_timeout 2s;
        proxy_timeout 900s;
        proxy_pass kube-apiserver;
    }
}
eof
nginx -t

由于是基于四层负载均衡，所以stream要放在http段外面

4.添加监控端口脚本

cat > /etc/keepalived/check_port.sh <<‘EOF‘
#!/bin/bash
# keepalived 监控端口脚本
CHK_PORT=$1
if [ -n "$CHK_PORT" ];then
        PORT_PROCESS=`ss -lnt|grep $CHK_PORT |wc -l`
        if [ $PORT_PROCESS -eq 0 ];then
                echo "Port $CHK_PORT Is Not Used,End."
                exit 1
        fi
else
        echo "Check Port Cant Be Empty!"
fi
eof
chmod +x /etc/keepalived/check_port.sh

5.配置keepalived主

cat > /etc/keepalived/keepalived.conf <<eof
! Configuration File for keepalived

global_defs {
   router_id 10.4.7.11

}

vrrp_script chk_nginx {
    script "/etc/keepalived/check_port.sh 7443"
    interval 2
    weight -20
}

vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 251
    priority 100
    advert_int 1
    mcast_src_ip 10.4.7.11
    nopreempt

    authentication {
        auth_type PASS
        auth_pass 11111111
    }
    track_script {
         chk_nginx
    }
    virtual_ipaddress {
        10.4.7.10
    }
}
eof

nopreempt非抢占式，即主nginx宕机，备接管vip，主nginx恢复，主vip不会恢复，需重启从keepalived，主vip才会恢复。
keepalived中master主机nopreempt表示非抢占机制。
通常如果master服务死掉后backup会变成master，但是当master服务又好了的时候 master此时会抢占VIP，这样就会发生两次切换对业务繁忙的网站来说是不好的。所以我们要在配置文件加入 nopreempt 非抢占，但是这个参数只能用于state 为backup，故我们在用HA的时候最好master和backup的state都设置成backup让其通过priority来竞争。

6.配置keepalived备

cat > /etc/keepalived/keepalived.conf <<‘eof‘
! Configuration File for keepalived

global_defs {
    router_id 10.4.7.12
}
vrrp_script chk_nginx {
    script "/etc/keepalived/check_port.sh 7443"
    interval 2
    weight -20
}
vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 251
    mcast_src_ip 10.4.7.12
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 11111111
    }
    track_script {
        chk_nginx
    }
    virtual_ipaddress {
        10.4.7.10
    }
}
eof

7.启动服务并检查

systemctl start nginx keepalived 
systemctl enable nginx keepalived 
systemctl status keepalived
netstat -lntup|grep nginx 
tcp        0      0 0.0.0.0:7443            0.0.0.0:*               LISTEN      13779/nginx: master 
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      13779/nginx: master 
tcp6       0      0 :::80                   :::*                    LISTEN      13779/nginx: master 
ip addr | tail -8
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:d7:a2:c7 brd ff:ff:ff:ff:ff:ff
    inet 10.4.7.11/24 brd 10.4.7.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 10.4.7.10/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fed7:a2c7/64 scope link 
       valid_lft forever preferred_lft forever

二进制部署K8S集群（十）Master节点之部署四层反向代理