在我们日常使用高可用集群时，都会使用到负载均衡工具对多个节点的负载进行转发。这里就不得不提到我们常用的一个负载均衡工具Nginx，Nginx官方提供的免费版本功能相对简单，大部分情况下我们都是用其进行负载均衡，对于应用的状态主要是依赖于其他的监控工具。如果对于小型的团队来说，部署专门的监控工具还需要资源，使用Nginx对应用进行探活监控可以节约这部分成本。
首先安装Nginx
使用yum安装nginx我这里使用的是1.16.1版本
yum install nginx
安装完成后可以获取源码安装命令
nginx -V
安装Nginx探活插件
下载源码与探活插件
wget https://nginx.org/download/nginx-1.16.1.tar.gz
wget https://github.com/yaoweibin/nginx_upstream_check_module/archive/refs/heads/master.zip
Nginx使用源码编译安装相关的依赖包
yum install pcre pcre-devel openssl openssl-devel gd gd-devel zlib patch libxml2-devel libxslt-devel perl-devel perl-ExtUtils-Embed perl zlib-devel patch
解压源码和插件包，我这里将两个软件包全部放到/opt下面进行解压
tar zxvf nginx-1.16.1.tar.gz
unzip nginx_upstream_check_module.zip
patch探活插件到Nginx源码中
cd /opt/nginx-1.16.1
patch -p1 < /opt/nginx_upstream_check_module-master/check_1.16.1+.patch
执行源码编译安装，添加http探活插件
./configure \
--prefix=/usr/share/nginx \
--sbin-path=/usr/sbin/nginx \
--modules-path=/usr/lib64/nginx/modules \
--conf-path=/etc/nginx/nginx.conf \
--error-log-path=/var/log/nginx/error.log \
--http-log-path=/var/log/nginx/access.log \
--http-client-body-temp-path=/var/lib/nginx/tmp/client_body \
--http-proxy-temp-path=/var/lib/nginx/tmp/proxy \
--http-fastcgi-temp-path=/var/lib/nginx/tmp/fastcgi \
--http-uwsgi-temp-path=/var/lib/nginx/tmp/uwsgi \
--http-scgi-temp-path=/var/lib/nginx/tmp/scgi \
--pid-path=/run/nginx.pid \
--lock-path=/run/lock/subsys/nginx \
--user=nginx \
--group=nginx \
--with-file-aio \
--with-ipv6 \
--with-http_ssl_module \
--with-http_v2_module \
--with-http_realip_module \
--with-stream_ssl_preread_module \
--with-http_addition_module \
--with-http_xslt_module=dynamic \
--with-http_image_filter_module=dynamic \
--with-http_sub_module \
--with-http_dav_module \
--with-http_flv_module \
--with-http_mp4_module \
--with-http_gunzip_module \
--with-http_gzip_static_module \
--with-http_random_index_module \
--with-http_secure_link_module \
--with-http_degradation_module \
--with-http_slice_module \
--with-http_stub_status_module \
--with-http_perl_module=dynamic \
--with-http_auth_request_module \
--with-mail=dynamic \
--with-mail_ssl_module \
--with-pcre \
--with-pcre-jit \
--with-stream=dynamic \
--with-stream_ssl_module \
--with-debug \
--with-cc-opt='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -m64 -mtune=generic' \
--with-ld-opt='-Wl,-z,relro -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -Wl,-E' \
--add-module=/opt/nginx_upstream_check_module-master/
使用Nginx负载Artifactory
Nginx可以作为Artifactory制品库的负载均衡器，用来负载Artifactory多个节点间的请求，Artifactory也可以自动生成Nginx配置文件，具体操作参考下图
配置探活
生成配置文件后，使用探活插件的配置方法，在Nginx的config 文件中进行配置。具体样例如下：
upstream artifactory {
server 192.168.1.2:8082;
server 192.168.1.3:8082;
check interval=2000 rise=2 fall=2 timeout=1000 type=http;
check_http_send "HEAD / HTTP/1.0\r\n\r\n";
check_http_expect_alive http_2xx http_3xx
}
upstream artifactory-direct {
server 192.168.1.2:8081;
server 192.168.1.3:8081;
check interval=2000 rise=2 fall=2 timeout=1000 type=http;
check_http_send "HEAD / HTTP/1.0\r\n\r\n";
check_http_expect_alive http_2xx http_3xx
}
server {
listen 80 ;
server_name artifactory.external.io;
if ($http_x_forwarded_proto = '') {
set $http_x_forwarded_proto $scheme;
}
## Application specific logs
## access_log /var/log/nginx/artifactory.external.io -access.log timing;
## error_log /var/log/nginx/artifactory.external.io -error.log;
rewrite ^/$ /ui/ redirect;
rewrite ^/ui$ /ui/ redirect;
chunked_transfer_encoding on;
client_max_body_size 0;
location / {
proxy_read_timeout 2400s;
proxy_pass_header Server;
proxy_cookie_path ~*^/.* /;
proxy_buffer_size 128k;
proxy_buffers 40 128k;
proxy_busy_buffers_size 128k;
proxy_pass http://artifactory;
proxy_set_header X-JFrog-Override-Base-Url $http_x_forwarded_proto://$host:$server_port;
proxy_set_header X-Forwarded-Port $server_port;
proxy_set_header X-Forwarded-Proto $http_x_forwarded_proto;
proxy_set_header Host $http_host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
location ~ ^/artifactory/ {
proxy_pass http://artifactory-direct;
}
}
location /status {
check_status;
access_log off;
}
}
探活配置成功之后访问，预置的location可以看到当前负载应用节点的健康状态
并且还支持json格式查看，方便我们进行数据采集