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如何用Keepalived+Nginx+Tomcat实现高可用Web集群

时间:2023-05-19 12:32

keepalived+nginx+tomcat 实现高可用web集群

如何用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 nginxnginx: /usr/local/nginx[root@localhost nginx-1.12.2]#

进入nginx子目录sbin启动nginx

[root@localhost sbin]# lsnginx[root@localhost sbin]# ./nginx &[1] 5768[root@localhost sbin]#

查看nginx是否启动

如何用Keepalived+Nginx+Tomcat实现高可用Web集群

或通过进程查看nginx启动情况

[root@localhost sbin]# ps -aux|grep nginxroot  5769 0.0 0.0 20484 608 ?  ss 14:03 0:00 nginx: master process ./nginxnobody  5770 0.0 0.0 23012 1620 ?  s 14:03 0:00 nginx: worker processroot  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.[ "$networking" = "no" ] && exit 0nginx="/usr/local/nginx/sbin/nginx"prog=$(basename $nginx)nginx_conf_file="/usr/local/nginx/conf/nginx.conf"[ -f /etc/sysconfig/nginx ] && . /etc/sysconfig/nginxlockfile=/var/lock/subsys/nginx make_dirs() { # make required directories user=`$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" instart)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 2esac

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 startstarting 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 ipvsadmyum 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

如何用Keepalived+Nginx+Tomcat实现高可用Web集群

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]192.168.43.101nginx server 01
keeepalived+nginx[backup]192.168.43.102nginx server 02
tomcat01192.168.43.103tomcat web server01
tomcat02192.168.43.104tomcat web server02
vip192.168.43.150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。

如何用Keepalived+Nginx+Tomcat实现高可用Web集群

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 startstarting 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。

如何用Keepalived+Nginx+Tomcat实现高可用Web集群

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。

如何用Keepalived+Nginx+Tomcat实现高可用Web集群

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keepalivedif [ $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  fifi

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 nginxroot  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.confnobody  6392 0.0 0.0 23008 1628 ?  s 19:13 0:00 nginx: worker processroot  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 keepalivedroot  6402 0.0 0.0 45920 1016 ?  ss 19:13 0:00 keepalived -d -f /etc/keepalived/keepalived.confroot  6403 0.0 0.0 48044 1468 ?  s 19:13 0:00 keepalived -d -f /etc/keepalived/keepalived.confroot  6404 0.0 0.0 50128 1780 ?  s 19:13 0:00 keepalived -d -f /etc/keepalived/keepalived.confroot  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 add1: 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 forever2: 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 forever3: 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 forever4: 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 add1: 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 forever2: 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 forever3: 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 forever4: 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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