keepalived+nginx+tomcat 实现高可用web集群
一、nginx的安装过程
1.下载nginx安装包,安装依赖环境包
(1)安装 c++编译环境
yum -y install gcc #c++
(2)安装pcre
yum -y install pcre-devel
(3)安装zlib
yum -y install zlib-devel
(4)安装nginx
定位到nginx 解压文件位置,执行编译安装命令
[root@localhost nginx-1.12.2]# pwd /usr/local/nginx/nginx-1.12.2 [root@localhost nginx-1.12.2]# ./configure && make && make install
(5)启动nginx
安装完成后先寻找那安装完成的目录位置
[root@localhost nginx-1.12.2]# whereis nginx nginx: /usr/local/nginx [root@localhost nginx-1.12.2]#
进入nginx子目录sbin启动nginx
[root@localhost sbin]# ls nginx [root@localhost sbin]# ./nginx & [1] 5768 [root@localhost sbin]#
查看nginx是否启动
或通过进程查看nginx启动情况
[root@localhost sbin]# ps -aux|grep nginx root 5769 0.0 0.0 20484 608 ? ss 14:03 0:00 nginx: master process ./nginx nobody 5770 0.0 0.0 23012 1620 ? s 14:03 0:00 nginx: worker process root 5796 0.0 0.0 112668 972 pts/0 r+ 14:07 0:00 grep --color=auto nginx [1]+ 完成 ./nginx [root@localhost sbin]#
到此nginx安装完成并启动成功。
(6)nginx快捷启动和开机启动配置
编辑nginx快捷启动脚本【 注意nginx安装路径 , 需要根据自己的nginx路径进行改动 】
[root@localhost init.d]# vim /etc/rc.d/init.d/nginx
#!/bin/sh # # nginx - this script starts and stops the nginx daemon # # chkconfig: - 85 15 # description: nginx is an http(s) server, http(s) reverse \ # proxy and imap/pop3 proxy server # processname: nginx # config: /etc/nginx/nginx.conf # 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 $nginx) nginx_conf_file="/usr/local/nginx/conf/nginx.conf" [ -f /etc/sysconfig/nginx ] && . /etc/sysconfig/nginx lockfile=/var/lock/subsys/nginx make_dirs() { # make required directories user=`$nginx -v 2>&1 | grep "configure arguments:" | sed 's/[^*]*--user=\([^ ]*\).*/\1/g' -` if [ -z "`grep $user /etc/passwd`" ]; then useradd -m -s /bin/nologin $user fi options=`$nginx -v 2>&1 | grep 'configure arguments:'` for opt in $options; do if [ `echo $opt | grep '.*-temp-path'` ]; then value=`echo $opt | cut -d "=" -f 2` if [ ! -d "$value" ]; then # echo "creating" $value mkdir -p $value && chown -r $user $value fi fi done } start() { [ -x $nginx ] || exit 5 [ -f $nginx_conf_file ] || exit 6 make_dirs 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 sleep 1 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: $0 {start|stop|status|restart|condrestart|try-restart|reload|force-reload|configtest}" exit 2 esac
为启动脚本授权 并加入开机启动
[root@localhost init.d]# chmod -r 777 /etc/rc.d/init.d/nginx [root@localhost init.d]# chkconfig nginx
启动nginx
[root@localhost init.d]# ./nginx start
将nginx加入系统环境变量
[root@localhost init.d]# echo 'export path=$path:/usr/local/nginx/sbin'>>/etc/profile && source /etc/profile
nginx命令 [ service nginx (start|stop|restart) ]
[root@localhost init.d]# service nginx start starting nginx (via systemctl): [ 确定 ]
tips: 快捷命令
service nginx (start|stop|restart)
二、keepalived安装和配置
1.安装keepalived依赖环境
yum install -y popt-devel yum install -y ipvsadm yum install -y libnl* yum install -y libnf* yum install -y openssl-devel
2.编译keepalived并安装
[root@localhost keepalived-1.3.9]# ./configure [root@localhost keepalived-1.3.9]# make && make install
3.将keepalive 安装成系统服务
[root@localhost etc]# mkdir /etc/keepalived [root@localhost etc]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
手动复制默认的配置文件到默认路径
[root@localhost etc]# mkdir /etc/keepalived [root@localhost etc]# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/ [root@localhost etc]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
为keepalived 创建软链接
[root@localhost sysconfig]# ln -s /usr/local/keepalived/sbin/keepalived /usr/sbin/
设置keepalived开机自启动
[root@localhost sysconfig]# chkconfig keepalived on 注意:正在将请求转发到“systemctl enable keepalived.service”。 created symlink from /etc/systemd/system/multi-user.target.wants/keepalived.service to /usr/lib/systemd/system/keepalived.service
启动keepalived服务
[root@localhost keepalived]# keepalived -d -f /etc/keepalived/keepalived.conf
关闭keepalived服务
[root@localhost keepalived]# killall keepalived
三、集群规划和搭建
环境准备:
centos 7.2
keepalived version 1.4.0 - december 29, 2017
nginx version: nginx/1.12.2
tomcat version:8
集群规划清单
虚拟机 | ip | 说明 |
---|---|---|
keepalived+nginx1[master] | 192.168.43.101 | nginx server 01 |
keeepalived+nginx[backup] | 192.168.43.102 | nginx server 02 |
tomcat01 | 192.168.43.103 | tomcat web server01 |
tomcat02 | 192.168.43.104 | tomcat web server02 |
vip | 192.168.43.150 | 虚拟漂移ip |
1.更改tomcat默认欢迎页面,用于标识切换web
更改tomcatserver01 节点root/index.jsp 信息,加入tomcatip地址,并加入nginx值,即修改节点192.168.43.103信息如下:
<div id="asf-box"> <h1>${pagecontext.servletcontext.serverinfo}(192.168.224.103)<%=request.getheader("x-nginx")%></h1> </div>
更改tomcatserver02 节点root/index.jsp信息,加入tomcatip地址,并加入nginx值,即修改节点192.168.43.104信息如下:
<div id="asf-box"> <h1>${pagecontext.servletcontext.serverinfo}(192.168.224.104)<%=request.getheader("x-nginx")%></h1> </div>
2.启动tomcat服务,查看tomcat服务ip信息,此时nginx未启动,因此request-header没有nginx信息。
3.配置nginx代理信息
1.配置master节点[192.168.43.101]代理信息
upstream tomcat { server 192.168.43.103:8080 weight=1; server 192.168.43.104:8080 weight=1; } server{ location / { proxy_pass http://tomcat; proxy_set_header x-nginx "nginx-1"; } #......其他省略 }
2.配置backup节点[192.168.43.102]代理信息
upstream tomcat { server 192.168.43.103:8080 weight=1; server 192.168.43.104:8080 weight=1; } server{ location / { proxy_pass http://tomcat; proxy_set_header x-nginx "nginx-2"; } #......其他省略 }
3.启动master 节点nginx服务
[root@localhost init.d]# service nginx start starting nginx (via systemctl): [ 确定 ]
此时访问 192.168.43.101 可以看到103和104节点tcomat交替显示,说明nginx服务已经将请求负载到了2台tomcat上。
4.同理配置backup[192.168.43.102] nginx信息,启动nginx后,访问192.168.43.102后可以看到backup节点已起到负载的效果。
4.配置keepalived 脚本信息
1. 在master节点和slave节点 /etc/keepalived目录下添加check_nginx.sh 文件,用于检测nginx的存货状况,添加keepalived.conf文件
check_nginx.sh文件信息如下:
#!/bin/bash #时间变量,用于记录日志 d=`date --date today +%y%m%d_%h:%m:%s` #计算nginx进程数量 n=`ps -c nginx --no-heading|wc -l` #如果进程为0,则启动nginx,并且再次检测nginx进程数量, #如果还为0,说明nginx无法启动,此时需要关闭keepalived if [ $n -eq "0" ]; then /etc/rc.d/init.d/nginx start n2=`ps -c nginx --no-heading|wc -l` if [ $n2 -eq "0" ]; then echo "$d nginx down,keepalived will stop" >> /var/log/check_ng.log systemctl stop keepalived fi fi
添加完成后,为check_nginx.sh 文件授权,便于脚本获得执行权限。
[root@localhost keepalived]# chmod -r 777 /etc/keepalived/check_nginx.sh
2.在master 节点 /etc/keepalived目录下,添加keepalived.conf 文件,具体信息如下:
vrrp_script chk_nginx { script "/etc/keepalived/check_nginx.sh" //检测nginx进程的脚本 interval 2 weight -20 } global_defs { notification_email { //可以添加邮件提醒 } } vrrp_instance vi_1 { state master #标示状态为master 备份机为backup interface ens33 #设置实例绑定的网卡(ip addr查看,需要根据个人网卡绑定) virtual_router_id 51 #同一实例下virtual_router_id必须相同 mcast_src_ip 192.168.43.101 priority 250 #master权重要高于backup 比如backup为240 advert_int 1 #master与backup负载均衡器之间同步检查的时间间隔,单位是秒 nopreempt #非抢占模式 authentication { #设置认证 auth_type pass #主从服务器验证方式 auth_pass 123456 } track_script { check_nginx } virtual_ipaddress { #设置vip 192.168.43.150 #可以多个虚拟ip,换行即可 } }
3.在backup节点 etc/keepalived目录下添加 keepalived.conf 配置文件
信息如下:
vrrp_script chk_nginx { script "/etc/keepalived/check_nginx.sh" //检测nginx进程的脚本 interval 2 weight -20 } global_defs { notification_email { //可以添加邮件提醒 } } vrrp_instance vi_1 { state backup #标示状态为master 备份机为backup interface ens33 #设置实例绑定的网卡(ip addr查看) virtual_router_id 51 #同一实例下virtual_router_id必须相同 mcast_src_ip 192.168.43.102 priority 240 #master权重要高于backup 比如backup为240 advert_int 1 #master与backup负载均衡器之间同步检查的时间间隔,单位是秒 nopreempt #非抢占模式 authentication { #设置认证 auth_type pass #主从服务器验证方式 auth_pass 123456 } track_script { check_nginx } virtual_ipaddress { #设置vip 192.168.43.150 #可以多个虚拟ip,换行即可 } }
tips: 关于配置信息的几点说明
state - 主服务器需配成master,从服务器需配成backup
interface - 这个是网卡名,我使用的是vm12.0的版本,所以这里网卡名为ens33
mcast_src_ip - 配置各自的实际ip地址
priority - 主服务器的优先级必须比从服务器的高,这里主服务器配置成250,从服务器配置成240
virtual_ipaddress - 配置虚拟ip(192.168.43.150)
authentication - auth_pass主从服务器必须一致,keepalived靠这个来通信
virtual_router_id - 主从服务器必须保持一致
5.集群高可用(ha)验证
step1 启动master机器的keepalived和 nginx服务
[root@localhost keepalived]# keepalived -d -f /etc/keepalived/keepalived.conf [root@localhost keepalived]# service nginx start
查看服务启动进程
[root@localhost keepalived]# ps -aux|grep nginx root 6390 0.0 0.0 20484 612 ? ss 19:13 0:00 nginx: master process /usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf nobody 6392 0.0 0.0 23008 1628 ? s 19:13 0:00 nginx: worker process root 6978 0.0 0.0 112672 968 pts/0 s+ 20:08 0:00 grep --color=auto nginx
查看keepalived启动进程
[root@localhost keepalived]# ps -aux|grep keepalived root 6402 0.0 0.0 45920 1016 ? ss 19:13 0:00 keepalived -d -f /etc/keepalived/keepalived.conf root 6403 0.0 0.0 48044 1468 ? s 19:13 0:00 keepalived -d -f /etc/keepalived/keepalived.conf root 6404 0.0 0.0 50128 1780 ? s 19:13 0:00 keepalived -d -f /etc/keepalived/keepalived.conf root 7004 0.0 0.0 112672 976 pts/0 s+ 20:10 0:00 grep --color=auto keepalived
使用 ip add 查看虚拟ip绑定情况,如出现192.168.43.150 节点信息则绑定到master节点
[root@localhost keepalived]# ip add 1: lo: <loopback,up,lower_up> mtu 65536 qdisc noqueue state unknown qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens33: <broadcast,multicast,up,lower_up> mtu 1500 qdisc pfifo_fast state up qlen 1000 link/ether 00:0c:29:91:bf:59 brd ff:ff:ff:ff:ff:ff inet 192.168.43.101/24 brd 192.168.43.255 scope global ens33 valid_lft forever preferred_lft forever inet 192.168.43.150/32 scope global ens33 valid_lft forever preferred_lft forever inet6 fe80::9abb:4544:f6db:8255/64 scope link valid_lft forever preferred_lft forever inet6 fe80::b0b3:d0ca:7382:2779/64 scope link tentative dadfailed valid_lft forever preferred_lft forever inet6 fe80::314f:5fe7:4e4b:64ed/64 scope link tentative dadfailed valid_lft forever preferred_lft forever 3: virbr0: <no-carrier,broadcast,multicast,up> mtu 1500 qdisc noqueue state down qlen 1000 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0 valid_lft forever preferred_lft forever 4: virbr0-nic: <broadcast,multicast> mtu 1500 qdisc pfifo_fast master virbr0 state down qlen 1000 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff
step 2 启动backup节点nginx服务和keepalived服务,查看服务启动情况,如backup节点出现了虚拟ip,则keepalvied配置文件有问题,此情况称为脑裂。
[root@localhost keepalived]# clear [root@localhost keepalived]# ip add 1: lo: <loopback,up,lower_up> mtu 65536 qdisc noqueue state unknown qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens33: <broadcast,multicast,up,lower_up> mtu 1500 qdisc pfifo_fast state up qlen 1000 link/ether 00:0c:29:14:df:79 brd ff:ff:ff:ff:ff:ff inet 192.168.43.102/24 brd 192.168.43.255 scope global ens33 valid_lft forever preferred_lft forever inet6 fe80::314f:5fe7:4e4b:64ed/64 scope link valid_lft forever preferred_lft forever 3: virbr0: <no-carrier,broadcast,multicast,up> mtu 1500 qdisc noqueue state down qlen 1000 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0 valid_lft forever preferred_lft forever 4: virbr0-nic: <broadcast,multicast> mtu 1500 qdisc pfifo_fast master virbr0 state down qlen 1000 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff
step 3 验证服务
浏览并多次强制刷新地址: http://192.168.43.150 ,可以看到103和104多次交替显示,并显示nginx-1,则表明 master节点在进行web服务转发。
step 4 关闭master keepalived服务和nginx服务,访问web服务观察服务转移情况
[root@localhost keepalived]# killall keepalived [root@localhost keepalived]# service nginx stop
此时强制刷新192.168.43.150发现 页面交替显示103和104并显示nginx-2 ,vip已转移到192.168.43.102上,已证明服务自动切换到备份节点上。
step 5 启动master keepalived 服务和nginx服务
此时再次验证发现,vip已被master重新夺回,并页面交替显示 103和104,此时显示nginx-1
四、keepalived抢占模式和非抢占模式
keepalived的ha分为抢占模式和非抢占模式,抢占模式即master从故障中恢复后,会将vip从backup节点中抢占过来。非抢占模式即master恢复后不抢占backup升级为master后的vip。
非抢占模式配置:
1> 在vrrp_instance块下两个节点各增加了nopreempt指令,表示不争抢vip
2> 节点的state都为backup 两个keepalived节点都启动后,默认都是backup状态,双方在发送组播信息后,会根据优先级来选举一个master出来。由于两者都配置了nopreempt,所以master从故障中恢复后,不会抢占vip。这样会避免vip切换可能造成的服务延迟。
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