配置nginx+keepalived高可用代理数据库ip端口

需求：配置nginx+keepalived高可用反向代理数据库ip端口（数据库服务器无法增加新SCAN IP或者需要隐藏数据库IP的情况下适用）

环境准备：
两台centos7.9
本机ip为：192.168.20.10和192.168.20.11
浮动IP为：192.168.20.20
主要思路：

• 1. 安装好操作系统，禁用selinux,firewalld
• 1. 安装nginx和keepalive软件
• 1. 配置conf文件
• 1. 测试ip漂移

[root@node1 ~]# cat /etc/redhat-release 
CentOS Linux release 7.9.2009 (Core)
[root@node1 ~]# ip a
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33:  mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:12:61:b7 brd ff:ff:ff:ff:ff:ff
    inet 192.168.20.10/24 brd 192.168.20.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::5900:8f03:c42:7d7a/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

以下内容两个节点都操作：
关闭防火墙等：

[root@node1 ~]# cat /etc/selinux/config 

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#     enforcing - SELinux security policy is enforced.
#     permissive - SELinux prints warnings instead of enforcing.
#     disabled - No SELinux policy is loaded.
SELINUX=disabled

systemctl stop firewalld
systemctl disable firewalld

安装依赖包和nginx和keepalived

[root@node1 ~]#
yum update -y
yum -y install epel-release
yum install gcc pcre-devel zlib-devel openssl-devel net-tools sysstat
yum install nginx nginx-mod-stream keepalived -y

配置keepalived.conf

[root@node1 ~]# cat /etc/keepalived/keepalived.conf 
global_defs {
   router_id LVS_DEVEL
   script_user root
   enable_script_security
}

vrrp_script chk_db_port ##该脚本必须放在vrrp的前面，有顺序问题
{
    script "/usr/local/src/nginx_check.sh"
#    script "

启停服务：

systemctl restart keepalived
systemctl restart nginx
systemctl stop nginx
systemctl start nginx

测试漂移IP：
1.任意节点停nginx：浮动ip会自动漂移到另外节点。

systemctl stop nginx
ip a

[root@node2 ~]# netstat -tunlp|grep LISTEN
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      1078/master         
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN      7037/nginx: master  
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      906/sshd            
tcp6       0      0 ::1:25                  :::*                    LISTEN      1078/master         
tcp6       0      0 :::22                   :::*                    LISTEN      906/sshd            
[root@node2 ~]# ip a
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33:  mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:be:8b:19 brd ff:ff:ff:ff:ff:ff
    inet 192.168.20.11/24 brd 192.168.20.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.20.20/24 scope global secondary ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::5900:8f03:c42:7d7a/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
    inet6 fe80::3a0a:e37:990:304a/64 scope link tentative noprefixroute dadfailed 
       valid_lft forever preferred_lft forever

复制

2.任意节点关机或重启系统，浮动ip也会自动漂移到另外节点。

观察日志：

tail -f /var/log/messages

相关参考：
Keepalived +VIP(虚拟IP) 漂移 部署系统高可用 离线部署|故障转移_内网vip+keepalived-CSDN博客