用Keepalived搭建雙Nginx server叢集 防止單點故障
阿新 • • 發佈：2018-12-19
綜述：
瀏覽器訪問虛擬IP: 192.168.1.57, 該虛擬IP被Keepalived接管，兩個Keepalived程序分別執行在物理IP為192.168.1.56和192.168.1.59伺服器上，這兩個伺服器上都執行著Nginx server。Nginx server都監聽虛擬IP 192.168.1.57. Nginx背後有一些web app叢集，已經配置成upstream.
為了防止Nginx自己成為單點瓶頸，這裡採用了雙Nginx server的方式。每個Server都是Ubuntu 12.04.
假定我的第一臺Ubuntu server物理IP地址是192.168.1.56，已經安裝了Nginx server，現在安裝Keepalived，後面稱這臺為master server.
apt-get install keepalived現在開始配置master server. 安裝完成keepalived後，通過檢視指令碼/etc/init.d/keepalived裡面發現，啟動配置檔案的路徑是
CONFIG=/etc/keepalived/keepalived.conf說明：# Settings for notifications global_defs { notification_email {[email protected] # Email address for notifications } notification_email_from [email protected]_company.com # The from address for the notifications smtp_server 127.0.0.1 smtp_connect_timeout 15}# Define the script used to check if haproxy is still working vrrp_script chk_http_port { script "/etc/keepalived/check_nginx.sh" # check Nginx is alive or not interval 2 # weight 2}# Configuation for the virtual interface vrrp_instance VI_1 { interface eth0 state MASTER # set this to BACKUP on the other machine priority 101 # set this to 100 on the other machine virtual_router_id 51 smtp_alert # Activate email notifications authentication { auth_type PASS auth_pass 1111 # Set this to some secret phrase } # The virtual ip address shared between the two loadbalancers virtual_ipaddress { 192.168.1.57 } # Use the script above to check if we should fail over track_script { chk_http_port }}
1. smtp_server必須要用127.0.0.1
2. 自己要建立一個檢查nginx程序的指令碼
/etc/keepalived/check_nginx.sh!/bin/bash# try to start nginx if nginx process is dead # shutdonw keepalived process if start nginx failed pid=`ps -C nginx --no-header |wc -l`if [ $pid -eq 0 ];then service nginx start sleep 3 if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then service keepalived stop fifiping 192.168.1.57PING 192.168.1.57 (192.168.1.57) 56(84) bytes of data.64 bytes from 192.168.1.57: icmp_req=1 ttl=64 time=0.024 ms64 bytes from 192.168.1.57: icmp_req=2 ttl=64 time=0.020 ms對192.168.1.59做相同的配置，略有變化的是：
vrrp_instance VI_1 { interface eth0 state BACKUP // changed priority 100 // changed通過輪流關閉master和backup，證明keepalived已經有效工作了。
參考資料：Keepalived官方文件真是夠差的。