Nginx+keepalived做双机热备加tomcat负载均衡

http://blog.csdn.net/beyondlpf/article/details/8240482环境说明：[html] view plain copynginx1:192.168.2.47nginx2:192.168.2.48tomcat1:192.168.2.49tomcat2:192.168.2.50vip:192.168.2.51

一.Nginx配置1.安装Nginx所需pcre库wget ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-8.10.tar.gz [html] view plain copytar -zxvf pcre-8.10.tar.gzcd pcre-8.10./configuremakemake install

2.安装Nginxwget http://nginx.org/download/nginx-0.8.52.tar.gz[html] view plain copygroupadd wwwuseradd -g www wwwtar zxvf nginx-0.8.52.tar.gzcd nginx-0.8.52/./configure --user=www --group=www --prefix=/usr/local/nginx --with-http_stub_status_module --with-http_ssl_modulemakemake install

注：如果出现以下错误[html] view plain copy./configure: error: SSL modules require the OpenSSL library.Centos需要安装openssl-develUbuntu则需要安装:sudo apt-get install libssl-dev

3.修改配置文件为以下内容：

user  www www;worker_processes 2;pid        logs/nginx.pid;worker_rlimit_nofile 51200;events{use epoll;worker_connections 51200;}http{include       mime.types;default_type  application/octet-stream;keepalive_timeout 120;server_tokens off;send_timeout 60;tcp_nodelay on;upstream  tomcats  {server 192.168.2.50:8080;server 192.168.2.49:8080;#ip_hash;       #在没有做共享session的情况下ip_hash可以解决session问题}server {listen  80;server_name  192.168.2.48;location / {proxy_pass        http://tomcats; proxy_set_header   Host             $host;proxy_set_header   X-Real-IP        $remote_addr;proxy_set_header   X-Forwarded-For  $proxy_add_x_forwarded_for;}log_format access_log  '$remote_addr - $remote_user [$time_local] $request ''"$status" $body_bytes_sent "$http_referer" ''"$http_user_agent" "$http_x_forwarded_for"';access_log  /usr/local/nginx/logs/access.log  access_log;} }

4.测试配置文件

/usr/local/nginx/sbin/nginx -t

如果出现以下情况

/usr/local/nginx/sbin/nginx: error while loading shared libraries: libpcre.so.0: or directory

解决方法：

sudo ln -s /usr/local/lib/libpcre.so.0 /usr/lib/libpcre.so.0

/usr/local/nginx/sbin/nginx -t显示以下信息为正确的

the configuration file /usr/local/nginx/conf/nginx.conf syntax is okconfiguration file /usr/local/nginx/conf/nginx.conf test is successful

5.优化内核参数vim /etc/sysctl.conf在最后添加

net.ipv4.tcp_max_syn_backlog = 65536net.core.netdev_max_backlog = 32768net.core.somaxconn = 32768net.core.wmem_default = 8388608net.core.rmem_default = 8388608net.core.rmem_max = 16777216net.core.wmem_max = 16777216net.ipv4.tcp_timestamps = 0net.ipv4.tcp_synack_retries = 2net.ipv4.tcp_syn_retries = 2net.ipv4.tcp_tw_recycle = 1net.ipv4.tcp_tw_reuse = 1net.ipv4.tcp_mem = 94500000 915000000 927000000net.ipv4.tcp_max_orphans = 3276800net.ipv4.ip_local_port_range = 1024  65535

保存退出后执行

sysctl -p

6.切割Nginx日志脚本

#!/bin/bashPATH_LOGS="/usr/local/nginx/logs"YEAR=`date -d "-1 days" +"%Y"`MONTH=`date -d "-1 days" +"%m"`mkdir -p $PATH_LOGS/$YEAR/$MONTHmv $PATH_LOGS/access.log $PATH_LOGS/$YEAR/$MONTH/access_$(date -d "-1 days" +"%Y%m%d").logkill -USR1 `cat $PATH_LOGS/nginx.pid`

把该脚本加到crontab每天00点执行注：备机的Nginx和以上安装步骤一样二.安装配置Keepalived1.下载所需要的软件wget http://keepalived.org/software/keepalived-1.1.19.tar.gz wget http://rpm5.org/files/popt/popt-1.16.tar.gz2.安装popt编译keepalived时需要popt，否则会报以下错误：

configure: error: Popt libraries is required

tar -zxvf popt-1.16.tar.gzcd popt-1.16./configuremakemake install

3.安装keepalived

tar -zxvf keepalived-1.1.19.tar.gzcd keepalived-1.1.19./configure --prefix=/usr/local/keepalivedmakemake install

4.修改配置文件为以下内容:vim /usr/local/keepalived/etc/keepalived/keepalived.conf

! Configuration File for keepalivedglobal_defs {router_id LVS_DEVEL}vrrp_script Monitor_Nginx {script "/root/scripts/monitor_nginx.sh" #根据自己的实际路径放置monitor_nginx.shinterval 2weight 2}vrrp_instance VI_1 {state MASTER interface eth0virtual_router_id 51priority 100advert_int 1authentication {auth_type PASSauth_pass 1234}track_script {Monitor_Nginx}virtual_ipaddress {192.168.2.51 }}

注：monitor_nginx.sh为监控nginx进程的脚本,内容如下

#!/bin/bashif [ "$(ps -ef | grep "nginx: master process"| grep -v grep )" == "" ]then /usr/local/nginx/sbin/nginxsleep 5if [ "$(ps -ef | grep "nginx: master process"| grep -v grep )" == "" ]thenkillall keepalivedfifi

5.启动keepalived

/usr/local/keepalived/sbin/keepalived -D -f /usr/local/keepalived/etc/keepalived/keepalived.conf

注:备机的keepalived的安装和上面一样，只要把配置文件改为以下(把MASTER改为BACKUP)

! Configuration File for keepalivedglobal_defs {router_id LVS_DEVEL}vrrp_script Monitor_Nginx {script "/root/scripts/monitor_nginx.sh"interval 2weight 2}vrrp_instance VI_1 {state BACKUP            #改为BACKUP interface eth0virtual_router_id 51priority 100            #比MASTER数值要低advert_int 1authentication {auth_type PASSauth_pass 1234}track_script {Monitor_Nginx}virtual_ipaddress {192.168.2.51 }}

三．测试步骤1． 访问VIP看是否能够正常访问后端的tomcat2． 停止其中一个tomcat看是否能将访问转到另一台上3． 停止两台nginx上任何一个nginx进程看监控进程脚本是否会自动启动nginx4． 停止任何一台nginx上的keepalived进程看另一台是否接管vip比如停止Master上的keepalived,例如如下killall keepalived,查看BACKUP机器是否已经接管，如果BACKUP接管后，BACKUP机器日志会是出下情况tail /var/log/syslog

Keepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATEKeepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATEKeepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 192.168.2.51

MASTER机器上日志会显示

Keepalived_vrrp: Terminating VRRP child process on signalKeepalived_vrrp: VRRP_Instance(VI_1) removing protocol VIPs.

现在把MASTER上的Keepalived重新启动，会看到MASTER重新接管VIP，并对外提供服务，BACKUP仍旧回到BACKUP STATE,如果不是这种情况，请检查配置文件和步骤.现在的BACKUP日志如下：

Keepalived_vrrp: VRRP_Instance(VI_1) Received higher prio advertKeepalived_vrrp: VRRP_Instance(VI_1) Entering BACKUP STATEKeepalived_vrrp: VRRP_Instance(VI_1) removing protocol VIPs.

Master日志如下：

Keepalived_vrrp: VRRP_Script(Monitor_Nginx) succeededKeepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATEKeepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATEKeepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 192.168.2.51