使用Nginx + Keepalived 实现高可用 Web 负载均衡笔记(虚拟机)

# yum install gcc gcc-c++ make automake autoconf libtool pcre pcre-devel zlib zlib-devel openssl openssl-devel ca-certificates

# cd /usr/local/src/# wget http://nginx.org/download/nginx-1.24.0.tar.gz

# cd /usr/local/src/# tar -zxvf nginx-1.24.0.tar.gz# cd nginx-1.24.0# ./configure --prefix=/usr/local/nginx# make && make install

# vi /usr/local/nginx/conf/nginx.conf

user root;
worker_processes 1;
#error_log logs/error.log;
#error_log logs/error.log notice;
#error_log logs/error.log info;
#pid logs/nginx.pid;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
#log_format main '$remote_addr - $remote_user [$time_local] "$request" '
# '$status $body_bytes_sent "$http_referer" '
# '"$http_user_agent" "$http_x_forwarded_for"';
#access_log logs/access.log main;
sendfile on;
#tcp_nopush on;
#keepalive_timeout 0;
keepalive_timeout 65;
#gzip on;
server {
listen 88;
server_name localhost;
#charset koi8-r;
#access_log logs/host.access.log main;
location / {
root html;
index index.html index.htm;
}
#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
}

# vi /usr/local/nginx/html/index.html

<h1>Welcome to nginx! 192.168.0.35</h1>

<h1>Welcome to nginx! 192.168.0.36</h1>

# firewall-cmd --zone=public --add-port=88/tcp --permanent#permanent永久生效,没有此参数防火墙重启便失效

systemctl status firewalld //或者 firewall-cmd --state

# systemctl start firewalld.service

firewall-cmd --reload  或者  service firewalld restart

firewall-cmd --zone=public --add-port=3306/tcp --permanent  //--permanent永久生效,没有此参数防火墙重启便失效

firewall-cmd --zone=public --remove-port=3306/tcp --permanent

systemctl stop firewalld

systemctl enable firewalld

systemctl disable firewalld

firewall-cmd --permanent --list-port

# /usr/local/nginx/sbin/nginx -t

nginx: the configuration file /usr/local/nginx/conf/nginx.conf syntax is oknginx: configuration file /usr/local/nginx/conf/nginx.conf test is successful

# /usr/local/nginx/sbin/nginx

# /usr/local/nginx/sbin/nginx -s reload

# vi /lib/systemd/system/nginx.service

[Unit]
Description=nginx
After=network.target
[Service]
Type=forking
ExecStart=/usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf
ExecReload=/usr/local/nginx/sbin/nginx -s reload
ExecStop=/usr/local/nginx/sbin/nginx -s quit
PrivateTmp=true
[Install]
WantedBy=multi-user.target

systemctl enable nginx.service

systemctl daemon-reload

systemctl status nginx.service

# cd /usr/local/src/# wget https://www.keepalived.org/software/keepalived-2.2.8.tar.gz

tar -xzvf keepalived-2.2.8.tar.gzcd keepalived-2.2.8/./configure --prefix=/usr/local/keepalived --sysconf=/etcmake && make install

cd /etc/keepalivedcp keepalived.conf.sample keepalived.conf

! Configuration File for keepalived
global_defs {
## keepalived 自带的邮件提醒需要开启 sendmail 服务。 建议用独立的监控或第三方 SMTP
router_id wongoing01    ## 标识本节点的字条串，通常为 hostname
}
## keepalived 会定时执行脚本并对脚本执行的结果进行分析，动态调整 vrrp_instance 的优先级。如果脚本执行结果为 0，并且 weight 配置的值大于 0，则优先级相应的增加。如果脚本执行结果非 0，并且 weight配置的值小于 0，则优先级相应的减少。其他情况，维持原本配置的优先级，即配置文件中 priority 对应的值。
vrrp_script chk_nginx {
script "/etc/keepalived/nginx_check.sh"     ## 检测 nginx 状态的脚本路径
interval 2     ## 检测时间间隔
weight -20   ## 如果条件成立，权重-20
}
## 定义虚拟路由， VI_1 为虚拟路由的标示符，自己定义名称
vrrp_instance VI_1 {
state MASTER      ## 主节点为 MASTER， 对应的备份节点为 BACKUP
interface ens33     ## 绑定虚拟 IP 的网络接口，与本机 IP 地址所在的网络接口相同， 虚拟机里面一般是ens33，物理主机通常是eth0
virtual_router_id 51    ## 虚拟路由的 ID 号， 两个节点设置必须一样， 可选 IP 最后一段使用, 相同的 VRID 为一个组，他将决定多播的 MAC 地址
priority 100            ## 节点优先级， 值范围 0-254， MASTER 要比 BACKUP 高
nopreempt            ## 优先级高的设置 nopreempt 解决异常恢复后再次抢占的问题
advert_int 1          ## 组播信息发送间隔，两个节点设置必须一样， 默认 1s
## 设置验证信息，两个节点必须一致
authentication {
auth_type PASS
auth_pass 1111      ## 真实生产，按需求对应该过来
}
## 将 track_script 块加入 instance 配置块
track_script {
chk_nginx        ## 执行 Nginx 监控的服务
}
## 虚拟 IP 池, 两个节点设置必须一样
virtual_ipaddress {
192.168.0.100      ## 虚拟 ip，可以定义多个
}
}

! Configuration File for keepalived
global_defs {
router_id wongoing02
}
vrrp_script chk_nginx {
script "/etc/keepalived/nginx_check.sh"
interval 2
weight -20
}
vrrp_instance VI_1 {
state BACKUP
interface ens33
virtual_router_id 51
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111!i!
}
track_script {
chk_nginx
}
virtual_ipaddress {
192.168.0.100
}
}

# vi /etc/keepalived/nginx_check.sh

#!/bin/bash
A=`ps -C nginx –no-header |wc -l`
if [ $A -eq 0 ];then
/usr/local/nginx/sbin/nginx
sleep 2
if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then
killall keepalived
fi
fi

# chmod +x /etc/keepalived/nginx_check.sh

# systemctl start keepalived.service

# systemctl status keepalived.service

systemctl enable keepalived.service

systemctl stop keepalived.servicesystemctl stop nginx.service

systemctl start nginx.servicesystemctl start keepalived.service

systemctl start keepalived.service