Keepalived + HAProxy 搭建【第二篇】Keepalived 安装与配置

2022-10-08 18:08:44

第一步：准备

1. 简介

　　本文搭建的是利用 Keepalived 实现 HAProxy 的热备方案，即两台主机上的 HAProxy 实例同时运行，其中全总较高的实例为 MASTER，MASTER出现异常时，另一台主机上的实例自动接管所有的流量。

　　在运行着 HAProxy 实例的两台主机上分别运行着 Keepalived 实例，这两个 Keepalived 争抢同一个虚 IP 地址，两个 HAProxy 也尝试着去绑定同一个虚 IP 地址上的端口。只能有一个 Keepalived 能抢到这个虚 IP，抢到这个虚 IP 的 Keepalived 的主机上的 HAProxy 即为当前的 MASTER。

　　Keepalived 内部维护一个权重值，权重值最高的 Keepalived 实例能够抢到虚 IP。Keepalived 会定期检查所在主机上的 HAProxy 的状态，状态健康时，则权重值增加。

2. 操作系统

CentOS-7-x86_64-Everything-1511

3. 安装包

keepalived-1.3.4.tar.gz

4. HAProxy 安装

参照 Keepalived + HAProxy 搭建【第一篇】HAProxy 的安装和配置在另一台主机（本文为192.168.6.129）上安装 HAProxy 实例。

5. 安装 psmisc

使用 killall -0 检查 HAProxy 服务是否存在。如果没有 killall 命令，则需要安装 psmisc 包。

# yum intall psmisc

6. 安装 openssl

# yum install openssl-devel

不安装 openssl，keepalived 编译的时候会报错：

7. 安装 libnl/libnl-3 库

# yum install libnl*

不安装 libnl/libnl-3，keepalived 编译的时候会报警告：

8. 安装

# yum install libnfnetlink-devel

不安装 libnfnetlink-devel，keepalived 编译的时候会报错：

第二步：安装与配置

1. 安装

# tar zxzf keepalived-1.3..tar.gz
# # cd keepalived-1.3.4

# ./configure --prefix=/usr/local/keepalived

# make

# make install

2. 配置

1）注册为系统服务

# cp /usr/local/keepalived/sbin/keepalived /usr/sbin/

# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
# touch /etc/init.d/keepalived
# chmod +x /etc/init.d/keepalived
# vi /etc/init.d/keepalived

/etc/init.d/keepalived 的文件内容：

#!/bin/sh

#

# Startup script for the Keepalived daemon

#

# processname: keepalived

# pidfile: /var/run/keepalived.pid

# config: /etc/keepalived/keepalived.conf

# chkconfig: - 21 79

# description: Start and stop Keepalived

# Source function library

. /etc/rc.d/init.d/functions

# Source configuration file (we set KEEPALIVED_OPTIONS there)

. /etc/sysconfig/keepalived

RETVAL=

prog="keepalived"

start() {

    echo -n $"Starting $prog: "

    daemon keepalived ${KEEPALIVED_OPTIONS}

    RETVAL=$?

    echo

    [ $RETVAL -eq  ] && touch /var/lock/subsys/$prog

}

stop() {

    echo -n $"Stopping $prog: "

    killproc keepalived

    RETVAL=$?

    echo

    [ $RETVAL -eq  ] && rm -f /var/lock/subsys/$prog

}

reload() {

    echo -n $"Reloading $prog: "

    killproc keepalived -

    RETVAL=$?

    echo

}

# See how we were called.

case "$1" in

    start)

        start

        ;;

    stop)

        stop

        ;;

    reload)

        reload

        ;;

    restart)

        stop

        start

        ;;

    condrestart)

        if [ -f /var/lock/subsys/$prog ]; then

            stop

            start

        fi

        ;;

    status)

        status keepalived

        RETVAL=$?

        ;;

    *)

        echo "Usage: $0 {start|stop|reload|restart|condrestart|status}"

        RETVAL=

esac

exit $RETVAL

2）编辑配置文件

# mkdir /etc/keepalived/

# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/

# vi /etc/keepalived/keepalived.conf

配置文件内容：

global_defs {

    router_id LVS_DEVEL  #虚拟路由名称

}

#HAProxy健康检查配置

vrrp_script chk_haproxy {

    script "killall -0 haproxy"  #使用killall -0检查haproxy实例是否存在，性能高于ps命令

    interval    #脚本运行周期

    weight    #每次检查的加权权重值

}

#虚拟路由配置

vrrp_instance VI_1 {

    state MASTER           #本机实例状态，MASTER/BACKUP，备机配置文件中请写BACKUP

    interface eno16777736      #本机网卡名称，使用ifconfig命令查看

    virtual_router_id    #虚拟路由编号，主备机保持一致

    priority            #本机初始权重，备机请填写小于主机的值（例如100）

    advert_int            #争抢虚地址的周期，秒

    virtual_ipaddress {

        192.168.6.131      #虚地址IP，主备机保持一致

    }

    track_script {

        chk_haproxy        #对应的健康检查配置

    }

}