Keepalived-2.0.0编译安装和启动方式详解

二、官网下载源码包(2018-5-26 最新版keepalived-2.0.0.tar.gz)

http://www.keepalived.org/download.html

cd /usr/local/src
wget http://www.keepalived.org/software/keepalived-1.2.0.tar.gz
tar xf keepalived-2.0.0.tar.gz 
cd keepalived-2.0.0
./configure  --prefix=/application/keepalived-2.0.0

一、编译安装Keepalived         

Keepalived是一个免费开源的,用C编写的类似于layer3, 4 & 7交换机制软件,具备我们平时说的第3层、第4层和第7层交换机的功能。主要提供loadbalancing(负载均衡)和high-availability(高可用)功能,负载均衡实现需要依赖Linux的虚拟服务内核模块(ipvs),而高可用是通过VRRP协议实现多台机器之间的故障转移服务。

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上图是Keepalived的功能体系结构,大致分两层:用户空间(user space)和内核空间(kernel space)。 
内核空间:主要包括IPVS(IP虚拟服务器,用于实现网络服务的负载均衡)和NETLINK(提供高级路由及其他相关的网络功能)两个部份。 

用户空间:

  • WatchDog:负载监控checkers和VRRP进程的状况
  • VRRP Stack:负载负载均衡器之间的失败切换FailOver,如果只用一个负载均稀器,则VRRP不是必须的。
  • Checkers:负责真实服务器的健康检查healthchecking,是keepalived最主要的功能。换言之,可以没有VRRP Stack,但健康检查healthchecking是一定要有的。
  • IPVS wrapper:用户发送设定的规则到内核ipvs代码
  • Netlink Reflector:用来设定vrrp的vip地址等。

六、keepalived.conf配置文件说明

       keepalived服务安装完成之后,后面的主要工作就是在keepalived.conf文件中配置HA和负载均衡。

完整的keepalived配置文件,主要包含三块:全局定义块、VRRP实例定义块和虚拟服务器定义块。全局定义块是必须的,如果keepalived只用来做ha,虚拟服务器是可选的。

#全局定义块
global_defs {
    # 邮件通知配置
    notification_email {
        email1
        email2
    }
    notification_email_from email
    smtp_server host
    smtp_connect_timeout num

    lvs_id string
    router_id string    ## 标识本节点的字条串,通常为hostname
}

#VRRP 实例定义块
vrrp_sync_group string { 
    group {
        string
        string
    }
}

vrrp_instance string {
    state MASTER|BACKUP
    virtual_router_id num
    interface string
    mcast_src_ip @IP 
    priority num
    advert_int num
    nopreempt
    smtp_alert
    lvs_sync_daemon_interface string 
    authentication {
        auth_type PASS|AH
        auth_pass string
    }

    virtual_ipaddress {  # Block limited to 20 IP addresses @IP
        @IP
        @IP
    }
}

#虚拟服务器定义块
virtual_server (@IP PORT)|(fwmark num) { 
    delay_loop num
    lb_algo rr|wrr|lc|wlc|sh|dh|lblc 
    lb_kind NAT|DR|TUN
    persistence_timeout num 
    protocol TCP|UDP
    real_server @IP PORT { 
        weight num
        notify_down /path/script.sh
        TCP_CHECK { 
            connect_port num 
            connect_timeout num
        }
    }

    real_server @IP PORT {
        weight num
        MISC_CHECK {
            misc_path /path_to_script/script.sh(or misc_path “/path_to_script/script.sh <arg_list>”)
        }
    }

    real_server @IP PORT {
        weight num
        HTTP_GET|SSL_GET {
            url { 
                # You can add multiple url block path alphanum
                digest alphanum
            }
            connect_port num
            connect_timeout num 
            nb_get_retry num 
            delay_before_retry num
        }
    }
}

  

2. 系统出现警告信息

!!! OpenSSL is not properly installed on your system. !!!
!!! Can not include OpenSSL headers files. !!!

解决方法:

[root@Web01 keepalived-2.0.0]# yum install -y openssl openssl-devel

虚拟服务器virtual_server定义块

  1. virtual_server:定义一个虚拟服务器,这个ip是virtual_ipaddress中定义的其中一个,后面一个空格,然后加上虚拟服务的端口号。 
    1> delay_loop:健康检查时间间隔,单位:秒 
    2> lb_algo:负载均衡调度算法,互联网应用常用方式为wlc或rr 
    3> lb_kind:负载均衡转发规则。包括DR、NAT、TUN 3种,一般使用路由(DR)转发规则。 
    4> persistence_timeout:http服务会话保持时间,单位:秒 
    5> protocol:转发协议,分为TCP和UDP两种
  2. real_server:真实服务器IP和端口,可以定义多个 
    1> weight:负载权重,值越大,转发的优先级越高 
    2> notify_down:服务停止后执行的脚本 
    3> TCP_金沙官网线上,CHECK:服务有效性检测 
    * connect_port:服务连接端口 
    * connect_timeout:服务连接超时时长,单位:秒 
    * nb_get_retry:服务连接失败重试次数 
    * delay_before_retry:重试连接间隔,单位:秒

 

全局定义块

1、email通知(notification_email、smtp_server、smtp_connect_timeout):用于服务有故障时发送邮件报警,可选项,不建议用。需要系统开启sendmail服务,建议用第三独立监控服务,如用Zabbix全面监控代替。 
2、lvs_id:lvs负载均衡器标识,在一个网络内,它的值应该是唯一的。 
3、router_id:用户标识本节点的名称,通常为hostname 
4、花括号{}:用来分隔定义块,必须成对出现。如果写漏了,keepalived运行时不会得到预期的结果。由于定义块存在嵌套关系,因此很容易遗漏结尾处的花括号,这点需要特别注意。

四、将Keepalived注册为系统服务

[root@Web01 keepalived-2.0.0]# mkdir /etc/keepalived/
[root@Web01 keepalived-2.0.0]# cp /usr/local/src/keepalived-2.0.0/keepalived/etc/init.d/keepalived /etc/init.d/
[root@Web01 keepalived-2.0.0]# cp /usr/local/src/keepalived-2.0.0/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
[root@Web01 keepalived-2.0.0]# cp /usr/local/src/keepalived-2.0.0/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/

这样就可以执行service keepalived [start | stop | reload | restart ]命令。(/etc/init.d/ [start | stop | reload | restart ])

 启动报“Starting keepalived: /bin/bash: keepalived: command not found”错误,具体日志如下:

[root@yoodb /]# service keepalived start
正在启动 keepalived:/bin/bash: keepalived: command not found
                                                           [失败]

解决方法:

cp /usr/local/src/keepalived-2.0.0/bin/keepalived /usr/sbin

重新执行如下输出后,表示启动成功

[root@m01 keepalived-2.0.0]# /etc/init.d/keepalived start
Starting keepalived: 
[root@m01 keepalived-2.0.0]# /etc/init.d/keepalived stop
Stopping keepalived:                                       [  OK  ]
[root@m01 keepalived-2.0.0]# /etc/init.d/keepalived start
Starting keepalived:                                       [  OK  ]
[root@m01 keepalived-2.0.0]# /etc/init.d/keepalived restart
Stopping keepalived:                                       [  OK  ]
Starting keepalived:                                       [  OK  ]
[root@m01 keepalived-2.0.0]# /etc/init.d/keepalived reload
Reloading keepalived: 
                                     [  OK  ]
加入开机启动
[root@m01 keepalived-2.0.0]# chkconfig keepalived on
[root@m01 keepalived-2.0.0]# chkconfig --list keepalived
keepalived 0:off 1:off 2:on 3:on 4:on 5:on 6:off

1.系统出现警告信息 “

checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... configure: error: newly created file is older than distributed files!
Check your system clock

”此报错是由于系统时间与硬件时间不一致导致的。

**************************************************************

linux系统的时间分为系统时间 和 硬件时间。 
硬件时间 就是指RTC中的时间,hwclock命令就是对这个时间操作。 
系统时间 是系统开机时读取硬件时间作为系统的时间,此后系统时钟独立运作,在系统关机时再将系统时间写回RTC。

date命令只操作系统时间,hwclock操作硬件时钟,在date 修改时间后 最好用hwclock 同步一下,以免系统非正常关机造成时间不同步。

[root@Web01 src]# date 
Sun Mar 19 09:35:08 CST 2017
[root@Web01 src]# hwclock 
Tue 03 Jul 2018 10:19:17 PM CST  -0.458468 seconds

同步时间,写入CMOS:

[root@Web01 src]# ntpdate ntp1.aliyun.com
 3 Jul 14:28:12 ntpdate[79878]: step time server 120.25.115.20 offset 40711428.938760 sec
[root@Web01 src]# date 
Tue Jul  3 14:28:19 CST 2018
[root@Web01 src]# hwclock 
Tue 03 Jul 2018 10:28:23 PM CST  -0.860282 seconds
[root@Web01 src]# hwclock 
Tue 03 Jul 2018 10:28:36 PM CST  -0.641474 seconds

问题解决!!!!  

3. 系统出现警告信息

“*** WARNING - this build will not support IPVS with IPv6. Please install libnl/libnl-3 dev libraries to support IPv6 with IPVS.”,具体日志如下:

Keepalived configuration
------------------------
Keepalived version       : 2.0.0
Compiler                 : gcc
Preprocessor flags       : 
Compiler flags           : -Wall -Wunused -Wstrict-prototypes -Wextra -Winit-self -g -O2 -D_GNU_SOURCE -fPIE -Wformat -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fexceptions --param=ssp-buffer-size=4
Linker flags             :  -pie
Extra Lib                :  -lcrypto  -lssl 
Use IPVS Framework       : Yes
IPVS use libnl           : No
IPVS syncd attributes    : No
IPVS 64 bit stats        : No
fwmark socket support    : Yes
Use VRRP Framework       : Yes
Use VRRP VMAC            : Yes
Use VRRP authentication  : Yes
With ip rules/routes     : Yes
Use BFD Framework        : No
SNMP vrrp support        : No
SNMP checker support     : No
SNMP RFCv2 support       : No
SNMP RFCv3 support       : No
DBUS support             : No
SHA1 support             : No
Use Json output          : No
libnl version            : None
Use IPv4 devconf         : No
Use libiptc              : No
Use libipset             : No
init type                : upstart
Build genhash            : Yes
Build documentation      : No

*** WARNING - this build will not support IPVS with IPv6. Please install libnl/libnl-3 dev libraries to support IPv6 with IPVS.

解决方法:执行yum命令yum -y install libnl libnl-devel解决上述警告问题

[root@Web01 keepalived-2.0.0]# yum -y install libnl libnl-devel 

VRRP实例定义块

  1. vrrp_sync_group:同步vrrp级,用于确定失败切换(FailOver)包含的路由实例个数。即在有2个负载均衡器的场景,一旦某个负载均衡器失效,需要自动切换到另外一个负载均衡器的实例是哪
  2. group:至少要包含一个vrrp实例,vrrp实例名称必须和vrrp_instance定义的一致
  3. vrrp_instance:vrrp实例名 
    1> state:实例状态,只有MASTER 和 BACKUP两种状态,并且需要全部大写。抢占模式下,其中MASTER为工作状态,BACKUP为备用状态。当MASTER所在的服务器失效时,BACKUP所在的服务会自动把它的状态由BACKUP切换到MASTER状态。当失效的MASTER所在的服务恢复时,BACKUP从MASTER恢复到BACKUP状态。 
    2> interface:对外提供服务的网卡接口,即VIP绑定的网卡接口。如:eth0,eth1。当前主流的服务器都有2个或2个以上的接口(分别对应外网和内网),在选择网卡接口时,一定要核实清楚。 
    3> mcast_src_ip:本机IP地址 
    4> virtual_router_id:虚拟路由的ID号,每个节点设置必须一样,可选择IP最后一段使用,相同的 VRID 为一个组,他将决定多播的 MAC 地址。 
    5> priority:节点优先级,取值范围0~254,MASTER要比BACKUP高 
    6> advert_int:MASTER与BACKUP节点间同步检查的时间间隔,单位为秒 
    7> lvs_sync_daemon_inteface:负载均衡器之间的监控接口,类似于 HA HeartBeat 的心跳线。但它的机制优于 Heartbeat,因为它没有“裂脑”这个问题,它是以优先级这个机制来规避这个麻烦的。在 DR 模式中,lvs_sync_daemon_inteface与服务接口interface使用同一个网络接口 
    8> authentication:验证类型和验证密码。类型主要有 PASS、AH 两种,通常使用PASS类型,据说AH使用时有问题。验证密码为明文,同一vrrp 实例MASTER与BACKUP使用相同的密码才能正常通信。 
    9> smtp_alert:有故障时是否激活邮件通知 
    10> nopreempt:禁止抢占服务。默认情况,当MASTER服务挂掉之后,BACKUP自动升级为MASTER并接替它的任务,当MASTER服务恢复后,升级为MASTER的BACKUP服务又自动降为BACKUP,把工作权交给原MASTER。当配置了nopreempt,MASTER从挂掉到恢复,不再将服务抢占过来。 
    11> virtual_ipaddress:虚拟IP地址池,可以有多个IP,每个IP占一行,不需要指定子网掩码。注意:这个IP必须与我们的设定的vip保持一致。

五、Keepalived启动参数说明

使用service keepalived start命令启动服务时,默认会将/etc/sysconfig/keepalived文件中KEEPALIVED_OPTIONS参数作为keepalived服务启动时的参数,并从/etc/keepalived/目录下加载keepalived.conf配置文件,或用-f参数指定配置文件的位置。

# Options for keepalived. See `keepalived --help' output and keepalived(8) and
# keepalived.conf(5) man pages for a list of all options. Here are the most
# common ones :
#
# --vrrp               -P    Only run with VRRP subsystem.
# --check              -C    Only run with Health-checker subsystem.
# --dont-release-vrrp  -V    Dont remove VRRP VIPs & VROUTEs on daemon stop.
# --dont-release-ipvs  -I    Dont remove IPVS topology on daemon stop.
# --dump-conf          -d    Dump the configuration data.
# --log-detail         -D    Detailed log messages.日志默认输出在/var/log/message文件中
# --log-facility       -S    0-7 Set local syslog facility (default=LOG_DAEMON)
#
KEEPALIVED_OPTIONS="-D

 运行keepalived --help可以查看启动时的可选参数,这些可选参数都可以配置在/etc/sysconfig/keepalived文件中的KEEPALIVED_OPTIONS选项中,作为服务启动时的参数。 

keepalived正常运行后,会启动3个进程,其中一个是父进程,负责监控其子进程。一个是vrrp子进程,另外一个是checkers子进程。

[root@m01 keepalived-2.0.0]# /application/keepalived/sbin/keepalived -f /application/keepalived/etc/keepalived/keepalived.conf   #检查配置参数
[root@m01 keepalived-2.0.0]# ps -ef |grep keep
root      22642      1  0 16:55 ?        00:00:00 keepalived -D
root      22644  22642  0 16:55 ?        00:00:00 keepalived -D
root      22645  22642  0 16:55 ?        00:00:00 keepalived -D

到此keepalived就安装完成了。

三、编译Keepalived过程中上述报错等问题解决后,没有其他报错,执行编译并安装

[root@Web01 keepalived-2.0.0]# make && make install
[root@Web01 keepalived-2.0.0]# echo $?
0

创建软连接(方便以后软件版本升级)
[root@Web01 keepalived-2.0.0]# ln -s /application/keepalived-2.0.0/ /application/keepalived

4. 系统出现错误信息

“configure: error: libnfnetlink headers missing”,具体日志如下:

checking for nl_socket_modify_cb in -lnl... yes
checking for linux/rtnetlink.h... yes
checking libnfnetlink/libnfnetlink.h usability... no
checking libnfnetlink/libnfnetlink.h presence... no
checking for libnfnetlink/libnfnetlink.h... no
configure: error: libnfnetlink headers missing

解决方法: yum install -y libnfnetlink-devel

安装完成以后,重新执行configure命令

[root@Web01 keepalived-2.0.0]# ./configure --prefix=/application/keepalived-2.0.0

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