快速入门-Keepalived+Nginx-HA高可用-不啰嗦-直接上-边实践边学
HI,朋友们,不啰嗦系列又更新了,今天的主要内容是Nginx,Nginx作为大家熟知的中间件,在很多业务场景中,或者说业务规模不大的场景中,一般我们都不去考虑所谓的HA和负载均衡,因为其自身的稳定性还是非常优异的,还没有见过单机版的Nginx崩溃,当然作为ITer的我们还是需要掌握其HA方案,今天就介绍下Keepalived + Nginx的HA高可用方案。其本质就是Keepalive虚拟出一个IP,可以实现IP漂移来保证一主一备的Nginx正常工作。
今天参与实验的主机有
- 192.168.31.165 应用Keepalived、Nginx
- 192.168.31.175 应用Keepalived、Nginx
- 192.168.31.155 web程序Python+Flask
- 192.168.31.185 web程序Python+Flask
- 192.168.31.195 模拟客户端访问
- 使用到的域名 x.little_nb.com y.little_nb.com
- 虚拟ip地址 192.168.31.200
今天实验的架构图如下:
今天的应用都是运行在容器中,首先我们先来安装docker
使用阿里云的源
yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
yum -y install docker-ce
systemctl enable docker
systemctl start docker
docker安装好以后我们来安装nginx,这里我为了快速,没有使用compose,直接命令创建的docker。
docker pull nginx 没有指定版本默认latest,等待镜像拉取完成
docker run -d \
--name nginx \
-v /data/nginx/html:/usr/share/nginx/html \
-v /data/conf/nginx.conf:/etc/nginx/nginx.conf \
-p 9000:80 \
-p 9001:9001 \
nginx:latest
直接复制创建,html文件随便创建一个,本地需要创建/data/nginx/html文件和文件夹 /data/nginx/nginx.conf文件和文件夹,/data/nginx/log文件夹,有日志可以配置到此路径,不过没有暂时没有映射。
在html文件夹下创建 index.html
内容如下
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>Load One</p>
</body>
</html>
在conf文件夹下面创建nginx.conf
user root;
worker_processes 1;
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"';
sendfile on;
keepalive_timeout 65;
upstream callback {
#ip_hash;
server 192.168.31.185:8331 ;
server 192.168.31.155:8331 ;
}
server {
listen 80;
server_name x.little_nb.com;
location / {
proxy_pass http://callback;
root /usr/share/nginx/html;
index index.html index.htm;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /home/nginx-demo/html;
}
}
server {
listen 9001;
server_name y.little_nb.com;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /home/nginx-demo/html;
}
}
}
格式大家自己调一下
9000端口是业务端口,9001是测试端口
以上nginx安装31.165、31.175同样的步骤。
接下来就是keepalived安装,docker pull keepalived,拉去keepalived的最新镜像
然后要创建一些文件和文件夹
/data/keepalived/keepalived.conf
/data/keepalived/nginx_check.sh
/data/keepalived/sendMail.py
31.175上keepalived.conf文件内容这是MASTER角色
! Configuration File for keepalived
vrrp_script chk_nginx {
script "/usr/local/etc/keepalived/nginx_check.sh"
interval 1
weight -2
}
vrrp_instance VI_1 {
state MASTER
interface enp12s0
virtual_router_id 120
mcast_src_ip 192.168.31.175
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_nginx
}
virtual_ipaddress {
192.168.31.200/24
}
notify_master "python3 /usr/local/etc/keepalived/sendMail.py master"
notify_backup "python3 /usr/local/etc/keepalived/sendMail.py backup"
notify_fault "python3 /usr/local/etc/keepalived/sendMail.py fault"
}
31.165上的keepalived.conf文件内容 这是BACKUP角色
! Configuration File for keepalived
vrrp_script chk_nginx {
script "/usr/local/etc/keepalived/nginx_check.sh" #nginx检测脚本
interval 1 #平均检测时间
weight -2 #失败就降权重,优先级降低,虚拟Vip转移
}
vrrp_instance VI_1 {
state BAKCUP #定义你的角色
interface enp5s0 #匹配你自己网卡名称
virtual_router_id 120 #router id一直 组队需要
mcast_src_ip 192.168.31.165 #本机iP
priority 99 #优先级定义
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_nginx
}
virtual_ipaddress {
192.168.31.200/24 #想定的虚拟IP
}
notify_master "python3 /usr/local/etc/keepalived/sendMail.py master"
notify_backup "python3 /usr/local/etc/keepalived/sendMail.py backup"
notify_fault "python3 /usr/local/etc/keepalived/sendMail.py fault"
}
31.165的sendMail.py 脚本
#!/usr/bin/env python
# -*- coding: UTF-8 -*-
import os
import sys
import socket
import smtplib
from email.mime.text import MIMEText
def SendMail(argv):
if len(argv) < 2:
print ('Error: parameter invalid!')
return
state = argv[1]
ip = '192.168.31.165'
subject = "keepalived: %s change to state: %s" % (ip, state)
conent = subject
message = MIMEText(conent,"plan","utf-8")
sender = "abc@163.com"
sender_pwd = "替换成你的授权码"
recver = "456@qq.com"
message['Subject'] = subject
message['To'] = recver
message['From'] = sender
smtp = smtplib.SMTP_SSL("smtp.163.com")
smtp.connect("smtp.163.com",465)
smtp.login(sender,sender_pwd)
smtp.sendmail(sender,[recver],message.as_string())
smtp.close()
if __name__ == "__main__":
SendMail(sys.argv)
31.175的sendMail.py脚本
#!/usr/bin/env python
# -*- coding: UTF-8 -*-
import os
import sys
import socket
import smtplib
from email.mime.text import MIMEText
def SendMail(argv):
if len(argv) < 2:
print ('Error: parameter invalid!')
return
state = argv[1]
ip = '192.168.31.175'
subject = "keepalived: %s change to state: %s" % (ip, state)
conent = subject
message = MIMEText(conent,"plan","utf-8")
sender = "abc@163.com"
sender_pwd = "替换成你的授权码"
recver = "456@qq.com"
message['Subject'] = subject
message['To'] = recver
message['From'] = sender
smtp = smtplib.SMTP_SSL("smtp.163.com")
smtp.connect("smtp.163.com",465)
smtp.login(sender,sender_pwd)
smtp.sendmail(sender,[recver],message.as_string())
smtp.close()
if __name__ == "__main__":
SendMail(sys.argv)
31.165的nginx_check.sh
#!/bin/bash
if [ "$(curl -sL -w '%{http_code}' http://192.168.31.165:9001 -o /dev/null)" = "200" ]; then
echo "Success"
exit 0
else
echo "Fail"
exit 1
fi
31.175的nginx_check.sh
if [ "$(curl -sL -w '%{http_code}' http://192.168.31.175:9001 -o /dev/null)" = "200" ]; then
echo "Success"
exit 0
else
echo "Fail"
exit 1
fi
docker run --cap-add=NET_ADMIN --cap-add=NET_BROADCAST --cap-add=NET_RAW --net=host -d --name keepalived \
-v /etc/localtime:/etc/localtime \
-v /data/keepalived/keepalived.conf:/usr/local/etc/keepalived/keepalived.conf \
-v /data/keepalived/nginx_check.sh:/usr/local/etc/keepalived/nginx_check.sh \
-v /data/keepalived/sendMail.py:/usr/local/etc/keepalived/sendMail.py \
osixia/keepalived:latest
docker 跑起来
这个高可用的原理就是原本挂载nginx的192.168.31.165和31.175依靠keepalived虚拟出来的31.200来达到一边故障另外一台主机可以继续工作,不管是keepalive还是其所在宿主机或者nginx服务失败,都会使31.200漂移到另外一台机器,以保证nginx指向的后端31.155和31.185能够继续给前端提供服务
keepalived开启后 ip地址会出现在已有网卡下面
首先我从195访问后端 本地host做了解析,我用的域名,这个和nginx.conf配置是对应的
curl x.little_nb.com:9000
测试四表五链 (返回)
keepalived目前虚拟ip是挂载在31.175,因为195访问域名等于nginx做解析31.200,后端显示来访IP是31.175,证明目前31.200挂载在31.175上面
将175上的nginx关闭,模拟nginx故障
这个时候会发生两件事,第一,175上的nginx检测脚本会生效,keepalived优先级会降级,
175上的keepalived降级
虚拟ip地址31.200会迁移到31.165上去
31.165上接收到了提示,说175降级到了98,我们是99.重新选举,然后31.200挂载在31.165上
第二,31.165上的邮件通知会发出来,提示keepalived角色状态发生改变
这个时候在从195的客户端访问域名解析到后端,就应该是31.165上的nginx在作用了
我们来模拟另外的场景,这个时候175上的nginx恢复了
检测脚本检测到以后会将31.175优先级keepalived提升到100
31.165又降级了,虚拟IP31.200挂载回了31.175上
从访问地址就可以看出来
我们再来测试一个场景,直接关闭MASTER 31.175的keepalived,不是关闭nginx
31.165直接接管了31.200虚拟IP
也收到了邮件,31.165变为了master
从后端可以看出来
那么我现在再来恢复31.175的keepalived
31.165上已经日志提示keepalived降级了删除了虚拟IP
31.175上提示虚拟ip已经回来
纯手工码字,在家实验,也有很多小坑,替大家踩了,重点是实验结果达到预期,在这种前提下nginx服务的SLA又提升了,当然还有很多细节可以完善,后续有相关教程再出,感兴趣的朋友照着来, 这个不抄袭,都是自己验证过了的。
鉴于有小伙伴要求配置文件下载,特地挂上链接,都是文本文件哈,如果不放心自己检查。
nginx 等文件 https://www.alipan.com/s/5jpi9wXZFR4 提取码: 6xf5 点击链接保存,或者复制本段内容,打开「阿里云盘」APP ,无需下载极速在线查看,视频原画倍速播放。