• Keepalived+Nginx+Tomcat 实现高可用Web集群


    https://www.jianshu.com/p/bc34f9101c5e

    Keepalived+Nginx+Tomcat 实现高可用Web集群

    0.3912018.01.08 20:28:59字数 1382阅读 6435
     
    集群规划图片

    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

     
    Niginx启动成功截图

    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

     
    集群规划图片

    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。

     
    Tomcat启动信息

    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。

     
    Nginx 负载效果

    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。

     
    Backup负载效果

    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的存活状况,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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  • 原文地址:https://www.cnblogs.com/zengpeng/p/11528099.html
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