nginx-zuul-dynamic-lb
场景痛点
在Spring Cloud微服务架构体系中，我们往往会部署一个Zuul集群来横向扩展我们的微服务应用，集群的上层是Nginx软负载，在实际情况中，往往会遇到Zuul宕机的尴尬事情，这时候从Nginx到这台机器的请求就会全部失效。此项目针对此痛点，用lua脚本实现定时拉取特定服务地址，动态无感知增减Zuul在Nginx中的负载节点。
如果您希望实现从Nginx直接到普通服务的动态节点负载，在下文配置服务名与Eureka注册中心地址即可。
OpenResty安装与配置
1、环境
yum -y install readline-devel pcre-devel openssl-devel gcc
2、下载解压OpenResty包
wget https://openresty.org/download/openresty-1.13.6.1.tar.gz
tar -zxvf openresty-1.13.6.1.tar.gz
3、下载ngx_cache_purge模块，该模块用于清理nginx缓存
cd openresty-1.13.6.1/bundle
wget http://labs.frickle.com/files/ngx_cache_purge-2.3.tar.gz
tar -zxvf ngx_cache_purge-2.3.tar.gz
4、下载nginx_upstream_check_module模块，该模块用于upstream健康检查
wget https://github.com/yaoweibin/nginx_upstream_check_module/archive/v0.3.0.tar.gz
tar -zxvf v0.3.0.tar.gz
5、OpenResty配置增加
cd openresty-1.13.6.1
./configure --prefix=/usr/servers --with-http_realip_module --with-pcre --with-luajit --add-module=./bundle/ngx_cache_purge-2.3/ --add-module=./bundle/nginx_upstream_check_module-0.3.0/ -j2
6、编译安装
make
make install
7、OpenResty没有http模块，需要单独安装
cd /usr/servers/lualib/resty
wget https://raw.githubusercontent.com/pintsized/lua-resty-http/master/lib/resty/http_headers.lua
wget https://raw.githubusercontent.com/pintsized/lua-resty-http/master/lib/resty/http.lua
8、项目脚本拷贝到这里
copy dynamic_eureka_balancer.lua into this dir
9、Nginx配置文件
vim /usr/servers/nginx/conf/nginx.conf
Nginx配置
http {
#sharing cache area
lua_shared_dict dynamic_eureka_balancer 128m;
init_worker_by_lua_block {
-- init eureka balancer
local file = require "resty.dynamic_eureka_balancer"
local balancer = file:new({dict_name="dynamic_eureka_balancer"})
--eureka server list
balancer.set_eureka_service_url({"127.0.0.1:8888", "127.0.0.1:9999"})
--eureka basic authentication
--use this setting if eureka has enabled basic authentication.
--note: basic authentication must use BASE64 encryption in `user:password` format
--balancer.set_eureka_service_basic_authentication("")
--The service name that needs to be monitored
balancer.watch_service({"zuul", "client"})
}
upstream springcloud_cn {
server 127.0.0.1:666; # Required, because empty upstream block is rejected by nginx (nginx+ can use 'zone' instead)
balancer_by_lua_block {
--The zuul name that needs to be monitored
local service_name = "zuul"
local file = require "resty.dynamic_eureka_balancer"
local balancer = file:new({dict_name="dynamic_eureka_balancer"})
--balancer.ip_hash(service_name) --IP Hash LB
balancer.round_robin(service_name) --Round Robin LB
}
}
server {
listen 80;
server_name localhost;
location / {
proxy_pass http://springcloud_cn/;
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
}