如何用Keepalived+Nginx+Tomcat实现高可用Web集群
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。
以上是如何用Keepalived+Nginx+Tomcat实现高可用Web集群的详细内容。更多信息请关注PHP中文网其他相关文章！
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