前言；
上篇博文《keepalived_nginx實現discuz負載均衡和高可用》講到，由於nginx將health_check功能放入到了商業版本，導致社區版本的nginx進行負載均衡，無法對後端的RS主機進行健康狀態檢測，所以現在準備使用tengine來取代nginx。我們只需要將前一章節VS主機上的nginx替換爲tengine即可。
配置：
Host VS1
卸載nginx，安裝tengine
# yum remove -y nginx # yum groupinstall -y "Development tools" "Server Platform Development" # yum install -y pcre-devel # wget http://tengine.taobao.org/download/tengine-2.0.3.tar.gz # tar -xf tengine-2.0.3.tar.gz # cd tengine-2.0.3 # ./configure # make && make install # echo "PATH=/usr/local/nginx/sbin/:$PATH" > /etc/profile.d/nginx.sh # exec bash
創建sorry_server頁面文件
# cp /usr/local/nginx/html/index.html{,.bak}
# echo "服務維護中,請稍後訪問." > /usr/local/nginx/html/index.html修改tengine配置文件
# vim /usr/local/nginx/conf/nginx.conf
http{
...
# 上游服務器, 即後端RS服務器.
upstream backend {
server 10.0.0.101 weight=1;
server 10.0.0.102 weight=1;
# sorry_server
server 10.0.0.111:8080 backup;
server 10.0.0.112:8080 backup;
# 健康檢查
check interval=3000 rise=1 fall=3 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 localhost;
# 當nginx將php代碼送至後端RS處理時請求頭中的Host值會是backend.
# php代碼在RS上處理時,其內部代碼會去請求圖片/層疊樣式表等靜態資源以填充頁面.
# 而php代碼去請求靜態資源時使用的是如http://backend/xxxx.gif這樣的url,自然是取不到的.
# 所以我們要在nginx向後代理遇到Host爲backend時,將其轉換爲127.0.0.1.
set $my_host $http_host;
if ($http_host = "backend") {
set $my_host "127.0.0.1";
}
location / {
proxy_pass http://backend;
proxy_set_header Host $my_host;
}
}
server {
listen 8080;
server_name localhost;
charset utf-8;
root /usr/local/nginx/html;
index index.html index.htm;
# sorry_server僅提供主頁面, 訪問其它資源也轉至主頁面.
location ~ .* {
error_page 404 /;
}
}啓動服務：
# nginx -t the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok configuration file /usr/local/nginx/conf/nginx.conf test is successful # nginx
Host VS2 做相同的配置
測試：
輪流關閉HostRS1和HostRS2，模擬RS主機宕機情形，可以發現用戶仍然可以正常訪問，說明用戶請求被調度到了正常的RS主機上
# tail /usr/local/nginx/logs/error.log 2016/05/14 14:57:37 [error] 26112#0: check time out with peer: 10.0.0.101:80 2016/05/14 14:57:41 [error] 26112#0: check time out with peer: 10.0.0.101:80 2016/05/14 14:57:46 [error] 26112#0: check time out with peer: 10.0.0.101:80 2016/05/14 14:57:50 [error] 26112#0: check time out with peer: 10.0.0.101:80 2016/05/14 14:57:55 [error] 26112#0: check time out with peer: 10.0.0.101:80 2016/05/14 14:57:59 [error] 26112#0: check time out with peer: 10.0.0.101:80
同時關閉RS1 和 RS2 會提示用戶服務維護中