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keepalived详解(lvs的dr模式的vip高可用)
发布时间：2019-06-07 15:39:12编辑：雪饮阅读（）
在一个月前曾经介绍过搭建lvs负载均衡的dr模式，今天要在此基础上实现vip的高可用。
前提
首先搭建一个lvs负载均衡的dr模式，我们通过ipvsadm以rr轮调方式实现rs1与rs2的httpd服务的负载均衡。
新增一个vip节点
上一步骤测试没有问题时，我们依据其vip的配置新增一个vip节点并配置ipvsadm规则，我们接下来就要在这两个vip之间进行高可用。首先就是两个vip节点上之前的绑定vip操作都撤销，因为我们要通过keepalived来实现vip绑定
keepalived安装配置
在两个vip上面分别安装keepalived-1.2.7.tar.gz
[root@localhost ~]# yum install kernel-devel -y
[root@localhost ~]# ls /usr/src/kernels/
2.6.18-308.el5-i686
解压keepalived并安装
[root@localhost keepalived-1.2.7]# yum install gcc openssl-devel
[root@localhost keepalived-1.2.7]# ./configure --sysconfdir=/etc/ --sbindir=/usr/sbin/ --with-kernel-dir=/usr/src/kernels/2.6.18-308.el5-i686/
[root@localhost keepalived-1.2.7]# make && make install
vip1上keepalived配置如：
[root@localhost keepalived-1.2.7]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 101
advert_int 1
authentication {
auth_type PASS
auth_pass keepalivedpass
}
virtual_ipaddress {
192.168.2.139/24 dev eth0 label eth0:0
}
}
virtual_server 192.168.2.139 80 {
delay_loop 6
lb_algo rr
lb_kind DR
nat_mask 255.255.255.0
#persistence_timeout 50
protocol TCP
real_server 192.168.2.104 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
real_server 192.168.2.167 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
}
vip2配置和vip1相同，只将如下配置修改：
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass keepalivedpass
}
virtual_ipaddress {
192.168.2.1/139 dev eth0 label eth0:0
}
}
在两个vip节点上都安装上ipvsadm
当上面的两个vip的keepalived都配置安装好后各自都启动keepalived服务后，就会在某个vip上看到vip绑定成功。
此时各自都安装ipvsadm后两个节点都可以看到ipvsadm上面自动有了rs1、rs2
[root@localhost keepalived]# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.2.139:80 rr
-> 192.168.2.167:80 Route 1 0 0
-> 192.168.2.104:80 Route 1 0 0
然后手动去停止rs1或rs2的httpd服务，然后在vip上ipvsadm中查看节点列表是否自动将刚才停止掉的rs节点移除掉，反正要测试某个rs的服务上线后，ipvsadm中是否也能自动新增上(注意：有时候你会发现没有及时的摘掉或添加上rs节点，需要耐心等下，有网络延迟的影响)
配置错误页(当所有rs节点都挂掉)
root@localhost keepalived]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 101
advert_int 1
authentication {
auth_type PASS
auth_pass keepalivedpass
}
virtual_ipaddress {
192.168.2.139/24 dev eth0 label eth0:0
}
}
virtual_server 192.168.2.139 80 {
delay_loop 6
lb_algo rr
lb_kind DR
nat_mask 255.255.255.0
#persistence_timeout 50
protocol TCP
sorry_server 127.0.0.1 80
real_server 192.168.2.104 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
real_server 192.168.2.167 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
}
那么此时我们每个ha上面就都要配置，且都要有一个httpd服务
经此配置后，当所有rs都挂掉后就会出现vip的httpd服务所提供的界面
配置ha健康状况检查
[root@localhost keepalived]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_schedown {
script "[ -e /etc/keepalived/down ] && exit 1 || exit 0"
interval 1
weight -5
fall 2
rise 1
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 101
advert_int 1
authentication {
auth_type PASS
auth_pass keepalivedpass
}
virtual_ipaddress {
192.168.2.139/24 dev eth0 label eth0:0
}
track_script {
chk_schedown
}
}
virtual_server 192.168.2.139 80 {
delay_loop 6
lb_algo rr
lb_kind DR
nat_mask 255.255.255.0
#persistence_timeout 50
protocol TCP
sorry_server 127.0.0.1 80
real_server 192.168.2.104 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
real_server 192.168.2.167 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
}
将两个vip都配置下
然后通过向master的vip上touch一个down文件，实现模型master的vip挂掉了，此时若另外一个vip上线了，而当前vip下线了则健康状况检查配置ok了，反之若删除了down文件则当前vip上线，对方vip下线，当然了这只是排除权重之后的结果，因为随着不断的down后，每个vip的权重都会有所变化，到时候肯定以权重高的优先绑定vip咯
配置vip切换、故障通知
分别是当前vip切换为master、backup以及当前vip故障时候的通知
[root@localhost keepalived-1.2.7]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_schedown {
script "[ -e /etc/keepalived/down ] && exit 1 || exit 0"
interval 1
weight -5
fall 2
rise 1
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass keepalivedpass
}
virtual_ipaddress {
192.168.2.139/24 dev eth0 label eth0:0
}
track_script {
chk_schedown
}
notify_master "/etc/keepalived/new_notify.sh -n master -a 192.168.2.139 -s sendmail"
notify_backup "/etc/keepalived/new_notify.sh -n backup -a 192.168.2.139 -s sendmail"
notify_fault "/etc/keepalived/new_notify.sh -n fault -a 192.168.2.139"
}
virtual_server 192.168.2.139 80 {
delay_loop 6
lb_algo rr
lb_kind DR
nat_mask 255.255.255.0
#persistence_timeout 50
protocol TCP
sorry_server 127.0.0.1 80
real_server 192.168.2.104 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
real_server 192.168.2.167 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
}
keepalived通知脚本进阶示例：
下面的脚本可以接受选项，其中：
-s, --service SERVICE,...：指定服务脚本名称，当状态切换时可自动启动、重启或关闭此服务；
-a, --address VIP: 指定相关虚拟路由器的VIP地址；
-m, --mode {mm|mb}：指定虚拟路由的模型，mm表示主主，mb表示主备；它们表示相对于同一种服务而方，其VIP的工作类型；
-n, --notify {master|backup|fault}：指定通知的类型，即vrrp角色切换的目标角色；
-h, --help：获取脚本的使用帮助；
#!/bin/bash
# Author: MageEdu <linuxedu@foxmail.com>
# description: An example of notify script
# Usage: notify.sh -m|--mode {mm|mb} -s|--service SERVICE1,... -a|--address VIP -n|--notify {master|backup|falut} -h|--help
#contact='linuxedu@foxmail.com'
helpflag=0
serviceflag=0
modeflag=0
addressflag=0
notifyflag=0
contact='root@localhost'
Usage() {
echo "Usage: notify.sh [-m|--mode {mm|mb}] [-s|--service SERVICE1,...] <-a|--address VIP> <-n|--notify {master|backup|falut}>"
echo "Usage: notify.sh -h|--help"
}
ParseOptions() {
local I=1;
if [ $# -gt 0 ]; then
while [ $I -le $# ]; do
case $1 in
-s|--service)
[ $# -lt 2 ] && return 3
serviceflag=1
services=(`echo $2|awk -F"," '{for(i=1;i<=NF;i++) print $i}'`)
shift 2 ;;
-h|--help)
helpflag=1
return 0
shift
;;
-a|--address)
[ $# -lt 2 ] && return 3
addressflag=1
vip=$2
shift 2
;;
-m|--mode)
[ $# -lt 2 ] && return 3
mode=$2
shift 2
;;
-n|--notify)
[ $# -lt 2 ] && return 3
notifyflag=1
notify=$2
shift 2
;;
*)
echo "Wrong options..."
Usage
return 7
;;
esac
done
return 0
fi
}
#workspace=$(dirname $0)
RestartService() {
if [ ${#@} -gt 0 ]; then
for I in $@; do
if [ -x /etc/rc.d/init.d/$I ]; then
/etc/rc.d/init.d/$I restart
else
echo "$I is not a valid service..."
fi
done
fi
}
StopService() {
if [ ${#@} -gt 0 ]; then
for I in $@; do
if [ -x /etc/rc.d/init.d/$I ]; then
/etc/rc.d/init.d/$I stop
else
echo "$I is not a valid service..."
fi
done
fi
}
Notify() {
mailsubject="`hostname` to be $1: $vip floating"
mailbody="`date '+%F %H:%M:%S'`, vrrp transition, `hostname` changed to be $1."
echo $mailbody | mail -s "$mailsubject" $contact
}
# Main Function
ParseOptions $@
[ $? -ne 0 ] && Usage && exit 5
[ $helpflag -eq 1 ] && Usage && exit 0
if [ $addressflag -ne 1 -o $notifyflag -ne 1 ]; then
Usage
exit 2
fi
mode=${mode:-mb}
case $notify in
'master')
if [ $serviceflag -eq 1 ]; then
RestartService ${services[*]}
fi
Notify master
;;
'backup')
if [ $serviceflag -eq 1 ]; then
if [ "$mode" == 'mb' ]; then
StopService ${services[*]}
else
RestartService ${services[*]}
fi
fi
Notify backup
;;
'fault')
Notify fault
;;
*)
Usage
exit 4
;;
esac
所需附件下载:keepalived-1.2.7.tar.gz
关键字词：keepalived,lvs,dr,vip,高可用