发布时间:2020-06-17 14:01:49编辑:admin阅读(2738)
本实验基于CentOS7.6 操作系统,总共5台设备,两台做后端web服务器,两台做lvs和keepalived,一台做客户机,实验以LVS(DR)+Keepalived和LVS(NAT)+Keepalived两种模式来做双机热备份,实验环境拓扑如下图所示:
从架构可以看出来,从用户的角度来说,会直接访问192.168.31.200,也就是说不管系统如何设计要保证此ip的可用性,
从架构师的角度考虑:
用户访问192.168.31.200,这是一个虚拟iP,用户不关心内部如何协调。
我们使用 192.168.31.54 作为主机 Master机器,然后使用keepalived 技术配置 HA(high avilable)配置高可用行,也就是说如果 分发的机器Master宕机了,keepalive会自动转到 backup机器,
这就是HA配置,保证master即使宕机了,也不影响转发;
master机器负责把用户的请求转发到 真实的机器, web1和web2,他们会按照一定的轮训机制,访问,如果web1宕机,master会自动转发到web2;
我们在两台负载均衡的机器上面,配置keepalived保证分发机器的高可用行HA;
系统的 IP配置如下:
服务器名 | 主机名 | IP地址 | 虚拟设备名 | 虚拟IP |
Director Server | lvs1 | 192.168.31.54 | enp0s3:0 | 192.168.31.200 |
Backup Server | lvs2 | 192.168.31.51 | enp0s3:0 | 192.168.31.200 |
Real Server1 | web1 | 192.168.31.113 | lo:0 | 192.168.31.200 |
Real Server2 | web2 | 192.168.31.150 | lo:0 | 192.168.31.200 |
请确保4台服务器关闭了防火墙
systemctl stop firewalld setenforce 0
登录主机web1和web2
安装nginx
# 安装Nginx源 yum -y install epel-release # 安装Nginx yum -y install nginx # 启动Nginx服务 systemctl start nginx # 加入开机自启 systemctl enable nginx # 备份原有默认页面 mv /usr/share/nginx/html/index.html /usr/share/nginx/html/index.html_bak
登录主机web1,修改默认页面
vi /usr/share/nginx/html/index.html
清空内容,完整内容如下:
This is Server 111
登录主机web2,修改默认页面
vi /usr/share/nginx/html/index.html
清空内容,完整内容如下:
This is Server 222
访问web1
访问web2
登录主机lvs1和lvs2
安装keepalived和lvs管理工具
yum -y install keepalived* ipvsadm
加载内核模块
modprobe ip_vs
备份配置文件
mv /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf_bak
登录主机lvs1
vi /etc/keepalived/keepalived.conf
内容如下:
global_defs { router_id LVS_TEST #服务器名字 } vrrp_instance VI_1 { state MASTER #配置主备,备用机此配置项为BACKUP interface enp0s3 #指定接口 virtual_router_id 51 #指定路由ID,主备必须一样 priority 101 #设置优先级,主略高于备份 advert_int 1 #设置检查时间 authentication { auth_type PASS #设置验证加密方式 auth_type 1234 #设置验证密码 } virtual_ipaddress { 192.168.31.200 } } virtual_server 192.168.31.200 80 { delay_loop 3 #健康检查时间 lb_algo rr #LVS调度算法 lb_kind DR #LVS工作模式 !persistence 60 #是否保持连接,!不保持 protocol TCP #服务采用TCP协议 real_server 192.168.31.113 80 { weight 1 #权重 TCP_CHECK { #TCP检查 connect_port 80 #检查端口80 connect_timeout 3 #超时时间3秒 nb_get_retry 3 #重试次数3次 delay_before_retry 4 #重试间隔4秒 } } real_server 192.168.31.150 80 { weight 1 TCP_CHECK { connect_port 80 connect_timeout 3 nb_get_retry 3 delay_before_retry 4 } } }
请根据实际情况修改红色部分
说明:
interface enp0s3 表示本地网卡为enp0s3
192.168.31.200 表示虚拟ip
重启keepalived服务
systemctl restart keepalived systemctl enable keepalived
验证虚拟IP是否生效
# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 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: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 08:00:27:04:34:88 brd ff:ff:ff:ff:ff:ff inet 192.168.31.54/24 brd 192.168.31.255 scope global noprefixroute dynamic enp0s3 valid_lft 31218sec preferred_lft 31218sec inet 192.168.31.200/32 scope global enp0s3 valid_lft forever preferred_lft forever inet6 fe80::a66d:efde:f19f:9882/64 scope link noprefixroute valid_lft forever preferred_lft forever
可以发现虚拟ip已经有了
登录主机lvs2
vi /etc/keepalived/keepalived.conf
LVS2的配置同LVS1,只需将配置文件中下面两处修改即可
内容如下:
global_defs { router_id LVS_TEST #服务器名字 } vrrp_instance VI_1 { state BACKUP #配置主备,备用机此配置项为BACKUP interface enp0s3 #指定接口 virtual_router_id 51 #指定路由ID,主备必须一样 priority 100 #设置优先级,主略高于备份 advert_int 1 #设置检查时间 authentication { auth_type PASS #设置验证加密方式 auth_type 1234 #设置验证密码 } virtual_ipaddress { 192.168.31.200 } } virtual_server 192.168.31.200 80 { delay_loop 3 #健康检查时间 lb_algo rr #LVS调度算法 lb_kind DR #LVS工作模式 !persistence 60 #是否保持连接,!不保持 protocol TCP #服务采用TCP协议 real_server 192.168.31.113 80 { weight 1 #权重 TCP_CHECK { #TCP检查 connect_port 80 #检查端口80 connect_timeout 3 #超时时间3秒 nb_get_retry 3 #重试次数3次 delay_before_retry 4 #重试间隔4秒 } } real_server 192.168.31.150 80 { weight 1 TCP_CHECK { connect_port 80 connect_timeout 3 nb_get_retry 3 delay_before_retry 4 } } }
重启keepalived服务
systemctl restart keepalived systemctl enable keepalived
查看虚拟IP
# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 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: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 08:00:27:d4:0e:fb brd ff:ff:ff:ff:ff:ff inet 192.168.31.51/24 brd 192.168.31.255 scope global noprefixroute dynamic enp0s3 valid_lft 31079sec preferred_lft 31079sec inet6 fe80::8cdb:32f0:4bbd:9294/64 scope link noprefixroute valid_lft forever preferred_lft forever inet6 fe80::a66d:efde:f19f:9882/64 scope link tentative noprefixroute dadfailed valid_lft forever preferred_lft forever
注意:此时是没有的。因为master和bakcup只能同时存在一个。只有当master异常时,bakcup才会出现虚拟ip。
登录主机lvs1,关掉主服务器的keepalived服务
systemctl stop keepalived
登录主机lvs2,验证备份的keepalived是否生效
# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 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: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 08:00:27:d4:0e:fb brd ff:ff:ff:ff:ff:ff inet 192.168.31.51/24 brd 192.168.31.255 scope global noprefixroute dynamic enp0s3 valid_lft 30713sec preferred_lft 30713sec inet 192.168.31.200/32 scope global enp0s3 valid_lft forever preferred_lft forever inet6 fe80::8cdb:32f0:4bbd:9294/64 scope link noprefixroute valid_lft forever preferred_lft forever inet6 fe80::a66d:efde:f19f:9882/64 scope link tentative noprefixroute dadfailed valid_lft forever preferred_lft forever
2台web服务器为lo:0绑定VIP地址、抑制ARP广播
登录主机web1,web2,编写以下脚本文件realserver.sh
vi /etc/init.d/realserver.sh
内容如下:
#!/bin/bash #description: Config realserver VIP=192.168.31.200 #/etc/rc.d/init.d/functions case "$1" in start) /sbin/ifconfig lo:0 $VIP netmask 255.255.255.255 broadcast $VIP /sbin/route add -host $VIP dev lo:0 echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce sysctl -p >/dev/null 2>&1 echo "RealServer Start OK" ;; stop) /sbin/ifconfig lo:0 down /sbin/route del $VIP >/dev/null 2>&1 echo "0" >/proc/sys/net/ipv4/conf/lo/arp_ignore echo "0" >/proc/sys/net/ipv4/conf/lo/arp_announce echo "0" >/proc/sys/net/ipv4/conf/all/arp_ignore echo "0" >/proc/sys/net/ipv4/conf/all/arp_announce echo "RealServer Stoped" ;; *) echo "Usage: $0 {start|stop}" exit 1 esac exit 0
请根据实际情况,修改VIP地址。
登录主机web1,web2,分别执行脚本
bash /etc/init.d/realserver.sh
执行完了之后,验证一下 使用ifconfig 你会发现 回环地址的网卡会多出一个lo:0的 网卡;
# ifconfig lo:0lo:0: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 192.168.31.200 netmask 255.255.255.255 loop txqueuelen 1000 (Local Loopback)
登录lvs1,查看VIP是否成功映射
# ipvsadm -L IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP MiWiFi-R3P-srv:http rr -> 192.168.31.113:http Route 1 0 0 -> 192.168.31.150:http Route 1 0 0
访问虚拟ip
可以看到,现在是访问的web1
登录主机web1,关闭nginx进程。
nginx -s stop
刷新页面
可以发现切换到web2了。
登录主机web1,启动Nginx
nginx
刷新页面
发现切换到web1了。
登录主机lvs1,此时的vip是在master节点上的。关闭keepalived服务
systemctl stop keepalived
查看vip,发现已经没有了
# ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 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: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 08:00:27:04:34:88 brd ff:ff:ff:ff:ff:ff inet 192.168.31.54/24 brd 192.168.31.255 scope global noprefixroute dynamic enp0s3 valid_lft 42290sec preferred_lft 42290sec inet6 fe80::a66d:efde:f19f:9882/64 scope link noprefixroute valid_lft forever preferred_lft forever
登录主机lvs2,查看vip,发现已经出现了。
# ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 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: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 08:00:27:d4:0e:fb brd ff:ff:ff:ff:ff:ff inet 192.168.31.51/24 brd 192.168.31.255 scope global noprefixroute dynamic enp0s3 valid_lft 42248sec preferred_lft 42248sec inet 192.168.31.200/32 scope global enp0s3 valid_lft forever preferred_lft forever inet6 fe80::8cdb:32f0:4bbd:9294/64 scope link noprefixroute valid_lft forever preferred_lft forever inet6 fe80::a66d:efde:f19f:9882/64 scope link tentative noprefixroute dadfailed valid_lft forever preferred_lft forever
此时,刷新页面,依然访问正常。
说明keepalived的HA特性是正常的。
本文参考链接:
https://blog.csdn.net/weixin_42342456/article/details/86100090
https://www.cnblogs.com/aspirant/p/6740556.html
47303
45507
36587
34101
28810
25424
24274
19469
18914
17483
5304°
5904°
5403°
5488°
6376°
5220°
5219°
5731°
5687°
6996°