最近，公司要我部署一个集群架构，选来选去还是选择了大家都很熟悉的基于DR的LVS+Keepalived做负载分发，然后使用轻量级的nginx做中 间代理层，这里呢先暂时实现一个简单web应用功能，对于代理功能和后续的web层部署、数据层安排将择机更新！
首先看一下集群框架：
下面开始我们的集群搭建行程：
一、IP规划：
做一件事情需要想想怎么去做既简单又有条理，我们做项目也应该如此。所以这里一定先做一个简单的规划，对于你后续测试的时候出现不能分发的情况有所解决。
负载均衡层 代理层 WEB层（待定）
LVS1：10.124.20.248 nginx1:10.124.20.250 web1
nginx2:10.124.20.251
LVS2：10.124.20.249 nginx3:10.124.20.252 web2
VIP：10.124.20.20 对应绑定的外网IP：117.78.3.253
备注：在云端虚拟机做架构，比在自己本地虚拟机做实验，要略有不同。初次接触云端虚拟机的同学可能有点犯迷糊，不知道这个ip地址是怎么分配的，怎么去管 理。我的老师教给一个最能解决问题的办法：在任何服务之前，首先要了解整个网络环境，然后根据环境部署服务，更改配置、规则等。关于云端虚拟机，它在整个 硬件防火墙和整个路由器封闭起来的一个大的局域网集群（这里为了好理解我们姑且认为云端就一个防火墙和一个路由器）。在这个集群中，又有很多网段的局域 网，每个企业在申请虚拟机的时候一般会建立一个虚拟机组，这个机组则对应着一个网段。
这里使用的网段是10.124.20.0/24， 给各台服务器分配唯一的IP地址。这里要特别说明一下，华为云技术人员建议使用的服务器固定ip在32-254之间，在2-31之间的IP地址作为候补之 用，比如说VIP就选用这里面，还有临时加虚拟机的话也可以选用。所以对于IP地址的规划是很重要的。另外说一下，这也是在生产环境中的经验吧，VIP必 须是和集群IP地址在一个网段，还要必须有别于集群IP地址，另外要提供网站访问服务或者测试，则需要将内网的VIP与一个公网IP进行绑定，在外部网络 浏览器访问外网IP就会直接映射到内网VIP上，然后就会实现我们所熟悉的功能，VIP漂移，LVS分发。小技巧：公网IP与单纯的一个内网ip做绑定是 不成功的，所以先把需要绑定公网IP的内网IP绑定到一个虚拟机上，然后再进行绑定，绑定完之后再进行更改IP地址。（比如说我要使用10.124.20.20做VIP，首先我把10.124.20.20绑定到一台虚拟机上，通过后台将外网IP117.78.3.253与10.124.20.20绑定，也就是做映射，最后再将10.124.20.20与虚拟解绑，这样就实现了预期目的）
二、源码安装&&配置
1.LVS+Keepalived搭建
1）LVS1：10.124.20.248&&LVS2：10.124.20.249
- cd /usr/local/src/
- tar xf ipvsadm-1.24.tar.gz
- tar xf keepalived-1.1.20.tar.gz
ipvsadm编译安装
- ln -s /usr/src/kernels/2.6.32-279.el6.x86_64/ /usr/src/linux #创建软连接
- cd /usr/local/src/ipvsadm-1.24
- make && make install
- #/sbin/ipvsadm -v #检测ipvsadm是否安装成功(或者：#watch ipvsadm –ln)
- ipvsadm v1.24 2005/12/10 (compiled with getopt_long and IPVS v1.2.1)
将ipvsadm设置成开机自启动服务
- chkconfig --add keepalived
- chkconfig keepalived on
Keepalived编译安装
- /usr/local/src/keepalived-1.1.20
- ./configure --prefix=/usr/local/keepalived --with-kernel-dir=/usr/src/kernels/2.6.32-279.el6.x86_64
- 返回信息：
- Keepalived configuration
- ------------------------
- Keepalived version : 1.1.20
- Compiler : gcc
- Compiler flags : -g -O2
- Extra Lib : -lpopt -lssl -lcrypto
- Use IPVS Framework : Yes
- IPVS sync daemon support : Yes
- Use VRRP Framework : Yes
- Use Debug flags : No
- make && make install
- 返回信息：
- install -d /usr/local/keepalived/bin
- install -m 755 ../bin/genhash /usr/local/keepalived/bin/
- install -d /usr/local/keepalived/share/man/man1
- install -m 644 ../doc/man/man1/genhash.1 /usr/local/keepalived/share/man/man1
将Keepalived做成服务：
- cd /usr/local/keepalived/
- cp etc/rc.d/init.d/keepalived /etc/rc.d/init.d/
- cp etc/sysconfig/keepalived /etc/sysconfig/
- mkdir /etc/keepalived
- cp etc/keepalived/keepalived.conf /etc/keepalived/
- cp sbin/keepalived /usr/sbin/
2）修改Keepalived.conf配置文件
- #cat /etc/keepalived/keepalived.conf #主LVS1：10.124.20.248
- ! Configuration File for keepalived
- global_defs {
- notification_email {
- qingbo.song@apicloud.com
- }
- notification_email_from qingbo.song@apicloud.com
- smtp_server 127.0.0.1
- # smtp_connect_timeout 30
- router_id LVS_DEVEL
- }
- vrrp_sync_group VGM {
- group {
- VI_1
- }
- notify_master "/opt/shell/arp.sh"
- notify_backup "/opt/shell/arp.sh"
- }
- vrrp_script chk_nginx {
- script "/opt/shell/check_nginx.sh"
- interval 1
- weight -2
- }
- vrrp_script chk_nginx2 {
- script "/opt/shell/check_nginx2.sh"
- interval 1
- weight -2
- }
- vrrp_script chk_nginx3 {
- script "/opt/shell/check_nginx3.sh"
- interval 1
- weight -2
- }
- vrrp_instance VI_1 {
- state MASTER
- interface eth0
- virtual_router_id 51
- priority 100
- advert_int 1
- authentication {
- auth_type PASS
- auth_pass yzkjTest
- }
- track_script {
- chk_nginx
- chk_nginx2
- chk_nginx3
- }
- virtual_ipaddress {
- 10.124.20.20
- }
- }
- virtual_server 10.124.20.20 80 {
- delay_loop 5
- lb_algo sh
- lb_kind DR
- persistence_timeout 60
- protocol TCP
- real_server 10.124.20.250 80 {
- weight 1
- TCP_CHECK {
- connect_timeout 10
- nb_get_retry 3
- delay_before_retry 3
- connect_port 80
- }
- }
- real_server 10.124.20.251 80 {
- weight 1
- TCP_CHECK {
- connect_timeout 10
- nb_get_retry 3
- delay_before_retry 3
- connect_port 80
- }
- }
- real_server 10.124.20.252 80 {
- weight 1
- TCP_CHECK {
- connect_timeout 10
- nb_get_retry 3
- delay_before_retry 3
- connect_port 80
- }
- }
- }
- #cat /etc/keepalived/keepalived.conf #备LVS1：10.124.20.249
- ! Configuration File for keepalived
- global_defs {
- notification_email {
- qingbo.song@apicloud.com
- }
- notification_email_from qingbo.song@apicloud.com
- smtp_server 127.0.0.1
- # smtp_connect_timeout 30
- router_id LVS_DEVEL
- }
- vrrp_sync_group VGM {
- group {
- VI_1
- }
- notify_master "/opt/shell/arp.sh"
- notify_backup "/opt/shell/arp.sh"
- }
- vrrp_script chk_nginx {
- script "/opt/shell/check_nginx.sh"
- interval 1
- weight -2
- }
- vrrp_script chk_nginx2 {
- script "/opt/shell/check_nginx2.sh"
- interval 1
- weight -2
- }
- vrrp_script chk_nginx3 {
- script "/opt/shell/check_nginx3.sh"
- interval 1
- weight -2
- }
- vrrp_instance VI_1 {
- state BACKUP
- interface eth0
- virtual_router_id 51
- priority 99
- advert_int 1
- authentication {
- auth_type PASS
- auth_pass yzkjTest
- }
- track_script {
- chk_nginx
- chk_nginx2
- chk_nginx3
- }
- virtual_ipaddress {
- 10.124.20.20
- }
- }
- virtual_server 10.124.20.20 80 {
- delay_loop 5
- lb_algo sh
- lb_kind DR
- persistence_timeout 60
- protocol TCP
- real_server 10.124.20.250 80 {
- weight 1
- TCP_CHECK {
- connect_timeout 10
- nb_get_retry 3
- delay_before_retry 3
- connect_port 80
- }
- }
- real_server 10.124.20.251 80 {
- weight 1
- TCP_CHECK {
- connect_timeout 10
- nb_get_retry 3
- delay_before_retry 3
- connect_port 80
- }
- }
- real_server 10.124.20.252 80 {
- weight 1
- TCP_CHECK {
- connect_timeout 10
- nb_get_retry 3
- delay_before_retry 3
- connect_port 80
- }
- }
- }
相关检测脚本：
- #cat /opt/shell/arp.sh
- #!/bin/bash
- VIP=10.124.20.20
- GATEWAY=10.124.20.1
- /sbin/arping -I eth0 -c 5 -s $VIP $GATEWAY &>/dev/null
- #cat /opt/shell/check_nginx.sh
- !/bin/bash
- url="http://10.124.20.250"
- status=$(/usr/bin/curl -s --head "$url" | awk '/HTTP/ {print $2}')
- if [ "$status" != "200" ]; then
- /opt/shell/arp.sh start
- fi
- #cat /opt/shell/check_nginx2.sh
- !/bin/bash
- url="http://10.124.20.251"
- status=$(/usr/bin/curl -s --head "$url" | awk '/HTTP/ {print $2}')
- if [ "$status" != "200" ]; then
- /opt/shell/arp.sh start
- fi
- #cat /opt/shell/check_nginx3.sh
- !/bin/bash
- url="http://10.124.20.252"
- status=$(/usr/bin/curl -s --head "$url" | awk '/HTTP/ {print $2}')
- if [ "$status" != "200" ]; then
- /opt/shell/arp.sh start
- fi
3）Keepalived服务启动（ifconfig eth0:1 10.124.20.248 netmask 255.255.255.255 up）
- service keepalived start #服务启动
- #ps -aux|grep keepalived #检测服务启动状态
- （/usr/local/keepalived/sbin/keepalived -D -f /etc/keepalived/keepalived.conf -D 显示在日志记录 -f 指定配置文件目录）
- Warning: bad syntax, perhaps a bogus '-'? See /usr/share/doc/procps-3.2.8/FAQ
- root 21205 0.0 0.0 36776 732 ? Ss 17:06 0:00 keepalived -D
- root 21207 0.0 0.1 38880 1936 ? S 17:06 0:00 keepalived -D
- root 21208 0.0 0.1 38880 1232 ? S 17:06 0:00 keepalived -D
- root 21301 0.0 0.0 103240 840 pts/0 S+ 17:07 0:00 grep keepalived
4）#设置开机启动服务
- （##echo “/usr/local/keepalived/sbin/keepalived -D -f /etc/keepalived/keepalived.conf” >> /etc/rc.d/rc.local）
- chkconfig --add keepalived
- chkconfig keepalived on
- service iptables stop
5）添加防火墙规则：
- iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT #使80端口提供对外服务
- iptables -A INPUT -d 224.0.0.0/8 -j ACCEPT
- iptables -A INPUT -p vrrp -j ACCEPT #基于DR模式，当用户发出请求后，只有DR响应ARP广播包，允许vrrp虚拟路由器冗余协议
- /etc/rc.d/init.d/iptables save #保存规则到iptables文件，使重启后生效）
6）开启转发功能；
- #vim /etc/sysctl.conf
- net.ipv4.ip_forward = 1
- #sysctl -p #使转发能够生效
三、nginx服务器的搭建
1）安装pcre-8.36.tar.gz
- cd /usr/local/src
- tar xf pcre-8.36.tar.gz
- cd pcre-8.36
- ./configure --prefix=/usr/local/pcre
- make && make install
2）安装nginx-1.5.1.tar.gz
- cd /usr/local/src
- tar xf nginx-1.5.1.tar.gz
- cd nginx-1.5.1
- ./configure --prefix=/usr/local/nginx --with-http_ssl_module --with-http_stub_status_module --with-pcre=/usr/local/src/pcre-8.36 --with-openssl=/usr/local/src/openssl-1.0.0c //这里跟的目录是源码目录，而不是源码安装后的目录
- make && make install
3）启动
编写启动脚本:
- vim /etc/init.d/nginx | chmod +x /etc/init.d/nginx
- #!/bin/sh
- #
- # nginx - this script starts and stops the nginx daemin
- #
- # chkconfig: - 85 15
- # description: Nginx is an HTTP(S) server, HTTP(S) reverse \
- # proxy and IMAP/POP3 proxy server
- # processname: nginx
- # config: /usr/local/nginx/conf/nginx.conf
- # pidfile: /usr/local/nginx/logs/nginx.pid
- # Source function library.
- . /etc/rc.d/init.d/functions
- # Source networking configuration.
- . /etc/sysconfig/network
- # Check that networking is up.
- [ "$NETWORKING" = "no" ] && exit 0
- nginx="/usr/local/nginx/sbin/nginx"
- prog=$(basename $nginx)
- NGINX_CONF_FILE="/usr/local/nginx/conf/nginx.conf"
- lockfile=/var/lock/subsys/nginx
- start() {
- [ -x $nginx ] || exit 5
- [ -f $NGINX_CONF_FILE ] || exit 6
- echo -n $"Starting $prog: "
- daemon $nginx -c $NGINX_CONF_FILE
- retval=$?
- echo
- [ $retval -eq 0 ] && touch $lockfile
- return $retval
- }
- stop() {
- echo -n $"Stopping $prog: "
- killproc $prog -QUIT
- retval=$?
- echo
- [ $retval -eq 0 ] && rm -f $lockfile
- return $retval
- }
- restart() {
- configtest || return $?
- stop
- start
- }
- reload() {
- configtest || return $?
- echo -n $"Reloading $prog: "
- killproc $nginx -HUP
- RETVAL=$?
- echo
- }
- force_reload() {
- restart
- }
- configtest() {
- $nginx -t -c $NGINX_CONF_FILE
- }
- rh_status() {
- status $prog
- }
- rh_status_q() {
- rh_status >/dev/null 2>&1
- }
- case "$1" in
- start)
- rh_status_q && exit 0
- $1
- ;;
- stop)
- rh_status_q || exit 0
- $1
- ;;
- restart|configtest)
- $1
- ;;
- reload)
- rh_status_q || exit 7
- $1
- ;;
- force-reload)
- force_reload
- ;;
- status)
- rh_status
- ;;
- condrestart|try-restart)
- rh_status_q || exit 0
- ;;
- *)
- echo $"Usage: $0 {start|stop|status|restart|condrestart|try-restart|reload|force-reload|configtest}"
- exit 2
- esac
service nginx start 启动服务
4）RS配置脚本
启动RS配置：
- sh /opt/RS.sh start
四、测试
浏览器访问测试117.78.3.253，能够返回想要的信息即为成功！
五、总结
使用LVS+Keepalived做负载均衡，首先先将内部各个服务器的iptables与selinux关闭，确保内部网络通畅，一般而言，将上述防火 墙关闭之后，安装上述配置文件提供的参数进行配置，是能够实现预期功能的。我的文档中可能提到过要设置iptables规则，这个要在测试通过之后，再打 开iptables，然后写上防火墙规则。通过查阅很多资料，看到很多人都在防火墙关闭的情况实验成功，看来防火墙与LVS的分发功能是多少有点冲突，对 于这方面的知识学习，有待于我们在今后的工作和学习中进行探索，我也将对后续知识在被人博客上做介绍，希望以后能在这个平台与大家一起交流、学习、成长！
qingbo.song@apicloud.com
2014-12-02
