keepalived高可用http服务实例

一、主机规划
本次实验利用五台CentOS7虚拟机，其中两台安装keepalived，两台作为安装httpd，提供web服务。

RS1	172.18.12.3	httpd
RS2	172.18.12.	http
HA1	172.18.12.1	keepalived
HA2	172.18.12.11	keepalived
客户机	172.18.12.250.243

虚拟ip：172.18.12.234

为了尽量减少环境对实验的干扰，需关闭防火墙和selinux

二、HA主机设定
1. 安装keepalive和检查工具ipvsadm

# yum install keepalived -y
# yum install -y ipvsadm

2.修改配置文件

# vim keepalived.conf

! Configuration File for keepalived
global_defs {
notification_email {
root@dy.com
}
notification_email_from Rex@keadm
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state MASTER
interface eno16777736
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.18.12.234/16
}
}
virtual_server 172.18.12.234 80 {
delay_loop 6
lb_algo rr
lb_kind DR
nat_mask 255.255.0.0
protocol TCP
real_server 172.18.12.3 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
real_server 172.18.12.4 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}

# systemctl restart keepalived.service

3.HA2备用路由器设定

! Configuration File for keepalived
global_defs {
notification_email {
root@dy.com
}
notification_email_from Rex@keadm
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state BACKUP
interface eno16777736
virtual_router_id 51
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.18.12.234/16
}
}
virtual_server 172.18.12.234 80 {
delay_loop 6
lb_algo rr
lb_kind DR
nat_mask 255.255.0.0
protocol TCP
real_server 172.18.12.3 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
real_server 172.18.12.4 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}

三、RS主机设置

# yum install httpd -y
# vim /var/www/html/index.html

<h1> www.RS2.com</h1>

# vim nkc.sh

#!/bin/bash
#
VIP='172.18.12.234'
case $1 in
start)
echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore
echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce
;;
stop)
echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore
echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore
echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce
echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce
esac
#
ifconfig lo:0  $VIP netmask 255.255.255.255 broadcast $VIP
route add -host $VIP dev lo:0

脚本说明：通过传参来实现对内核参数的控制，控制arp解析通告级别，以及设置虚拟ip，并由一条路由来指定，凡是经过172.18.12.234进来的主机我们都让其从io：0出去。注意必须限制通告级别再设置ip。

#bash vkc.sh   start

[root@localhost ~]# ifconfig

eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
inet 172.18.253.86  netmask 255.255.0.0  broadcast 172.18.255.255
inet6 fe80::20c:29ff:fe3c:38be  prefixlen 64  scopeid 0x20<link>
ether 00:0c:29:3c:38:be  txqueuelen 1000  (Ethernet)
RX packets 115308  bytes 26442683 (25.2 MiB)
RX errors 0  dropped 2  overruns 0  frame 0
TX packets 15460  bytes 1839145 (1.7 MiB)
TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
inet 127.0.0.1  netmask 255.0.0.0
inet6 ::1  prefixlen 128  scopeid 0x10<host>
loop  txqueuelen 0  (Local Loopback)
RX packets 166  bytes 15346 (14.9 KiB)
RX errors 0  dropped 0  overruns 0  frame 0
TX packets 166  bytes 15346 (14.9 KiB)
TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
lo:0: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
inet 172.18.12.234  netmask 255.255.255.255
loop  txqueuelen 0  (Local Loopback)

# systemctl start httpd

RS2设置同上

五、测试过程
1.启动从主机查看ipvs规则

# ipvsadm -Ln

IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  172.18.12.234:80 rr
-> 172.18.12.3:80               Route   1      0          0
-> 172.18.12.4:80               Route   1      0          0

可以发现，keepalived启动之后会自动加载配置文件中的集群服务规则