二、企业 keepalived 高可用项目实战
1、Keepalived VRRP 介绍
keepalived是什么 keepalived是集群管理中保证集群高可用的一个服务软件，用来防止单点故障。 keepalived工作原理 keepalived是以VRRP协议为实现基础的，VRRP全称Virtual Router Redundancy Protocol，即虚拟路由冗余协议。 虚拟路由冗余协议，可以认为是实现路由器高可用的协议，即将N台提供相同功能的路由器组成一个路由器组，这个组里面有一个master和多个backup，master上面有一个对外提供服务的vip（该路由器所在局域网内其他机器的默认路由为该vip），master会发组播，当backup收不到vrrp包时就认为master宕掉了，这时就需要根据VRRP的优先级来选举一个backup当master。这样的话就可以保证路由器的高可用了。 keepalived主要有三个模块，分别是core、check和vrrp。core模块为keepalived的核心，负责主进程的启动、维护以及全局配置文件的加载和解析。check负责健康检查，包括常见的各种检查方式。vrrp模块是来实现VRRP协议的。 ============================================== 脑裂 split barin： Keepalived的BACKUP主机在收到不MASTER主机报文后就会切换成为master，如果是它们之间的通信线路出现问题，无法接收到彼此的组播通知，但是两个节点实际都处于正常工作状态，这时两个节点均为master强行绑定虚拟IP，导致不可预料的后果，这就是脑裂。 解决方式: 1、添加更多的检测手段，比如冗余的心跳线（两块网卡做健康监测），ping对方等等。尽量减少"裂脑"发生机会。(指标不治本，只是提高了检测到的概率)； 2、设置仲裁机制。两方都不可靠，那就依赖第三方。比如启用共享磁盘锁，ping网关等。(针对不同的手段还需具体分析)； 3、爆头，将master停掉。然后检查机器之间的防火墙。网络之间的通信
2、Nginx+keepalived实现七层的负载均衡
Nginx通过Upstream模块实现负载均衡
upstream 支持的负载均衡算法
主机清单：
| 主机名 | ip | 系统 | 用途 |
|---|---|---|---|
| Proxy-master | 172.16.147.155 | centos7.5 | 主负载 |
| Proxy-slave | 172.16.147.156 | centos7.5 | 主备 |
| Real-server1 | 172.16.147.153 | Centos7.5 | web1 |
| Real-server2 | 172.16.147.154 | centos7.5 | Web2 |
| Vip for proxy | 172.16.147.100 |
配置安装nginx 所有的机器，关闭防火墙和selinux [root@proxy-master ~]# systemctl stop firewalld //关闭防火墙 [root@proxy-master ~]# sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/sysconfig/selinux //关闭selinux，重启生效 [root@proxy-master ~]# setenforce 0 //关闭selinux，临时生效 安装nginx， 全部4台 [root@proxy-master ~]# cd /etc/yum.repos.d/ [root@proxy-master yum.repos.d]# vim nginx.repo [nginx-stable] name=nginx stable repo baseurl=http://nginx.org/packages/centos/$releasever/$basearch/ gpgcheck=0 enabled=1 [root@proxy-master yum.repos.d]# yum install yum-utils -y [root@proxy-master yum.repos.d]# yum install nginx -y
一、实施过程
1、选择两台nginx服务器作为代理服务器。
2、给两台代理服务器安装keepalived制作高可用生成VIP
3、配置nginx的负载均衡
# 两台配置完全一样
[root@proxy-master ~]# vim /etc/nginx/nginx.conf
user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;
include /usr/share/nginx/modules/*.conf;
events {
worker_connections 1024;
}
http {
log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';
access_log /var/log/nginx/access.log main;
sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 65;
types_hash_max_size 2048;
include /etc/nginx/mime.types;
default_type application/octet-stream;
include /etc/nginx/conf.d/*.conf;
upstream backend {
server 172.16.147.154:80 weight=1 max_fails=3 fail_timeout=20s;
server 172.16.147.153:80 weight=1 max_fails=3 fail_timeout=20s;
}
server {
listen 80;
server_name localhost;
location / {
proxy_pass http://backend;
proxy_set_header Host $host:$proxy_port;
proxy_set_header X-Forwarded-For $remote_addr;
}
}
}
Keepalived实现调度器HA
注：主/备调度器均能够实现正常调度
1. 主/备调度器安装软件
[root@proxy-master ~]# yum install -y keepalived
[root@proxy-slave ~]# yum install -y keepalived
[root@proxy-master ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
[root@proxy-master ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
router_id directory1 #辅助改为directory2
}
vrrp_instance VI_1 {
state MASTER #定义主还是备
interface ens33 #VIP绑定接口
virtual_router_id 80 #整个集群的调度器一致
priority 100 #back改为50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.16.147.100/24 # vip
}
}
[root@proxy-slave ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
[root@proxy-slave ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
router_id directory2
}
vrrp_instance VI_1 {
state BACKUP #设置为backup
interface ens33
nopreempt #设置到back上面，不抢占资源
virtual_router_id 80
priority 50 #辅助改为50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.16.147.100/24
}
}
3. 启动KeepAlived（主备均启动）
[root@proxy-master ~]# systemctl enable keepalived
[root@proxy-slave ~]# systemctl start keepalived
[root@proxy-master ~]# 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
inet 172.16.147.100/32 scope global lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:ec:8a:fe brd ff:ff:ff:ff:ff:ff
inet 172.16.147.155/24 brd 172.16.147.255 scope global noprefixroute dynamic ens33
valid_lft 1115sec preferred_lft 1115sec
inet 172.16.147.101/24 scope global secondary ens33
valid_lft forever preferred_lft forever
到此：
可以解决心跳故障keepalived
不能解决Nginx服务故障
4. 扩展对调度器Nginx健康检查（可选）两台都设置
思路：
让Keepalived以一定时间间隔执行一个外部脚本，脚本的功能是当Nginx失败，则关闭本机的Keepalived
(1) script
[root@proxy-master ~]# vim /etc/keepalived/check_nginx_status.sh
#!/bin/bash
/usr/bin/curl -I http://localhost &>/dev/null
if [ $? -ne 0 ];then
# /etc/init.d/keepalived stop
systemctl stop keepalived
fi
[root@proxy-master ~]# chmod a+x /etc/keepalived/check_nginx_status.sh
(2). keepalived使用script
! Configuration File for keepalived
global_defs {
router_id director1
}
vrrp_script check_nginx {
script "/etc/keepalived/check_nginx_status.sh"
interval 5
}
vrrp_instance VI_1 {
state MASTER
interface ens33
virtual_router_id 80
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.246.16/24
}
track_script {
check_nginx
}
}
注：必须先启动nginx，再启动keepalived
3、LVS_Director + KeepAlived
| 主机名 | ip | 系统 | 用途 |
|---|---|---|---|
| client | 172.16.147.1 | mac | 客户端 |
| lvs-keepalived-master | 172.16.147.154 | centos7.5 | 分发器 |
| lvs-keepalived-slave | 172.16.147.155 | centos7.5 | 分发器备 |
| test-nginx1 | 172.16.147.153 | centos7.5 | web1 |
| test-nginx2 | 172.16.147.156 | centos7.5 | web2 |
| vip | 172.16/147.101 |
LVS_Director + KeepAlived
KeepAlived在该项目中的功能：
1. 管理IPVS的路由表（包括对RealServer做健康检查）
2. 实现调度器的HA
http://www.keepalived.org
Keepalived所执行的外部脚本命令建议使用绝对路径
实施步骤：
1. 主/备调度器安装软件
[root@lvs-keepalived-master ~]# yum -y install ipvsadm keepalived
[root@lvs-keepalived-slave ~]# yum -y install ipvsadm keepalived
2. Keepalived
lvs-master
[root@lvs-keepalived-master ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
router_id lvs-keepalived-master #辅助改为lvs-backup
}
vrrp_instance VI_1 {
state MASTER
interface ens33 #VIP绑定接口
virtual_router_id 80 #VRID 同一组集群，主备一致
priority 100 #本节点优先级，辅助改为50
advert_int 1 #检查间隔，默认为1s
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.16.147.101/24 # 可以写多个vip
}
}
virtual_server 172.16.147.101 80 { #LVS配置
delay_loop 3
lb_algo rr #LVS调度算法
lb_kind DR #LVS集群模式（路由模式）
net_mask 255.255.255.0
protocol TCP #健康检查使用的协议
real_server 172.16.147.153 80 {
weight 1
inhibit_on_failure #当该节点失败时，把权重设置为0，而不是从IPVS中删除
TCP_CHECK { #健康检查
connect_port 80 #检查的端口
connect_timeout 3 #连接超时的时间
}
}
real_server 172.16.147.156 80 {
weight 1
inhibit_on_failure
TCP_CHECK {
connect_timeout 3
connect_port 80
}
}
}
[root@lvs-keepalived-slave ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
router_id lvs-keepalived-slave
}
vrrp_instance VI_1 {
state BACKUP
interface ens33
nopreempt #不抢占资源
virtual_router_id 80
priority 50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.16.147.101/24
}
}
virtual_server 172.16.147.101 80 {
delay_loop 3
lb_algo rr
lb_kind DR
net_mask 255.255.255.0
protocol TCP
real_server 172.16.147.153 80 {
weight 1
inhibit_on_failure
TCP_CHECK {
connect_port 80
connect_timeout 3
}
}
real_server 172.16.147.156 80 {
weight 1
inhibit_on_failure
TCP_CHECK {
connect_timeout 3
connect_port 80
}
}
}
3. 启动KeepAlived（主备均启动）
[root@lvs-keepalived-master ~]# systemctl start keepalived
[root@lvs-keepalived-master ~]# systemctl enable keepalived
[root@lvs-keepalived-master ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 172.16.147.101:80 rr persistent 20
-> 172.16.147.153:80 Route 1 0 0
-> 172.16.147.156:80 Route 0 0 0
4. 所有RS配置(nginx1,nginx2)
配置好网站服务器，测试所有RS
[root@test-nginx1 ~]# yum install -y nginx
[root@test-nginx2 ~]# yum install -y nginx
[root@test-nginx1 ~]# echo "ip addr add dev lo 172.16.147.101/32" >> /etc/rc.local
[root@test-nginx1 ~]# echo "net.ipv4.conf.all.arp_ignore = 1" >> /etc/sysctl.conf
[root@test-nginx1 ~]# echo "net.ipv4.conf.all.arp_announce = 2" >> /etc/sysctl.conf
[root@test-nginx1 ~]# sysctl -p
[root@test-nginx1 ~]# echo "web1..." >> /usr/share/nginx/html/index.html
[root@test-nginx1 ~]# systemctl start nginx
[root@test-nginx1 ~]# chmod +x /etc/rc.local
LB集群测试
所有分发器和Real Server都正常
主分发器故障及恢复
MySQL+Keepalived
Keepalived+mysql 自动切换
项目环境：
VIP 192.168.246.100
mysql1 192.168.246.162 keepalived-master
mysql2 192.168.246.163 keepalived-salve一、mysql 主主同步 （不使用共享存储，数据保存本地存储）
二、安装keepalived
三、keepalived 主备配置文件
四、mysql状态检测脚本/root/bin/keepalived_check_mysql.sh
五、测试及诊断
实施步骤：
一、mysql 主主同步
二、安装keepalived---两台机器都操作
[root@mysql-keepalived-master ~]# yum -y install keepalived
[root@mysql-keepalived-slave ~]# yum -y install keepalived
三、keepalived 主备配置文件
192.168.246.162 master配置
[root@mysql-keepalived-master ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
[root@mysql-keepalived-master ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalivedglobal_defs {
router_id master
}
vrrp_script check_run {
script "/etc/keepalived/keepalived_chech_mysql.sh"
interval 5
}vrrp_instance VI_1 {
state MASTER
interface ens33
virtual_router_id 89
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.246.100/24
}
track_script {
check_run
}
}
slave 192.168.246.163 配置
[root@mysql-keepalived-slave ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
[root@mysql-keepalived-slave ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalivedglobal_defs {
router_id backup
}
vrrp_script check_run {
script "/etc/keepalived/keepalived_check_mysql.sh"
interval 5
}vrrp_instance VI_1 {
state BACKUP
nopreempt
interface ens33
virtual_router_id 89
priority 50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.246.100/24
}
track_script {
check_run
}
}
四、mysql状态检测脚本/root/keepalived_check_mysql.sh（两台MySQL同样的脚本）
版本一：简单使用：
[root@mysql-keepalived-master ~]# vim /etc/keepalived/keepalived_check_mysql.sh
#!/bin/bash
/usr/bin/mysql -uroot -p'QianFeng@2019!' -e "show status" &>/dev/null
if [ $? -ne 0 ] ;then
# service keepalived stop
systemctl stop keepalived
fi
[root@mysql-keepalived-master ~]# chmod +x /etc/keepalived/keepalived_check_mysql.sh
==========================================================================
两边均启动keepalived
方式一:
[root@mysql-keepalived-master ~]# systemctl start keepalived
[root@mysql-keepalived-master ~]# systemctl enable keepalived
方式二:
# /etc/init.d/keepalived start
# /etc/init.d/keepalived start
# chkconfig --add keepalived
# chkconfig keepalived on
注意:在任意一台机器作为客户端。在测试的时候记得检查mysql用户的可不可以远程登录。
补充
keepalived 配置lvs
! Configuration File for keepalived
global_defs {
router_id lvs-master
}
vrrp_instance VI_1 {
state MASTER
nopreempt
interface em1
# mcast src ip 发送多播包的地址，如果不设置默认使用绑定网卡的primary ip
mcast_src_ip 10.3.131.50
# unicast src ip 如果两节点的上联交换机禁用了组播，则只能采用vrrp单播通告的方式
# unicast_src_ip xx.xx.xx.xx
# unicast_peer {
# xx.xx.xx.xx
# }
virtual_router_id 80
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.3.131.221
}
# 当前节点成为主节点时触发的脚本 notify_master
notify_master "/etc/keepalived/mail.sh master"
# 当前节点转为备节点时触发的脚本 notify_backup
notify_backup "/etc/keepalived/mail.sh backup"
# 当前节点转为失败状态时触发的脚本 notify_fault
notify_fault "/etc/keepalived/mail.sh fault"
}
virtual_server 10.3.131.221 80 {
# 健康检查时间间隔，小于6秒
delay_loop 6
# 轮询算法
lb_algo rr
# lvs 模式
lb_kind DR
nat_mask 255.255.255.0
# 会话保持时间
persistence_timeout 20
# 使用的协议
protocol TCP
sorry_server 2.2.2.2 80
real_server 10.3.131.30 80 {
# 权重
weight 1
# 在服务器健康检查失效时，将其设为0，而不是直接从ipvs中删除
inhibit_on_failure
#在检测到server up后执行脚本
notify_up /etc/keepalived/start.sh start
#在检测到server down后执行脚本
notify_down /etc/keepalived/start.sh shutdown
# 采用url方式检查
HTTP_GET {
url {
path /index.html
digest 481bf8243931326614960bdc17f99b00
}
# 检测端口
connect_port 80
# 连接超时时间
connect_timeout 3
# 重试次数
nb_get_retry 3
# 重连间隔时间
delay_before_retry 2
}
}
}
检查方式:
HTTP_GET URL检查
TCP_GET 端口检查
节点配置
keepalived 自带通知组件并不是很友好，这里我们采用自定义邮件通知方式
1、shell 邮件告警
# yum install -y mailx
# vim /etc/mail.rc
set from=newrain_wang@163.com
set smtp=smtp.163.com
set smtp-auth-user=newrain_wang@163.com
set smtp-auth-password=XXXXXXXXXXXXXX
set smtp-auth=login
set ssl-verify=ignore
# 脚本代码
#!/bin/bash
to_email='1161733918@qq.com'
ipaddress=`ip -4 a show dev ens33 | awk '/brd/{print $2}'`
notify() {
mailsubject="${ipaddress}to be $1, vip转移"
mailbody="$(date +'%F %T'): vrrp 飘移, $(hostname) 切换到 $1"
echo "$mailbody" | mail -s "$mailsubject" $to_email
}
case $1 in
master)
notify master
;;
backup)
notify backup
;;
fault)
notify fault
;;
*)
echo "Usage: $(basename $0) {master|backup|fault}"
exit 1
;;
esac
2、配置文件
# master配置
! Configuration File for keepalived
global_defs {
router_id directory1
}
vrrp_instance VI_1 {
state MASTER
interface ens33
virtual_router_id 80
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.96.100/24
}
notify_master "/etc/keepalived/script/sendmail.sh master"
notify_backup "/etc/keepalived/script/sendmail.sh backup"
notify_fault "/etc/keepalived/script/sendmail.sh fault"
}
# 解释：
#当前节点成为主节点时触发的脚本 notify_master
#当前节点转为备节点时触发的脚本 notify_backup
#当前节点转为失败状态时触发的脚本 notify_fault
#back配置
! Configuration File for keepalived
global_defs {
router_id directory2
}
vrrp_instance VI_1 {
state MASTER
interface ens33
nopreempt
virtual_router_id 80
priority 50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.91.134/24
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
自己总结的：
两个负载均衡器
master backup
master down掉，backup上
master发组播
如果虚拟机版本是7.7 ，需要systemctl kill keepalived
实例 间隔时间 验证
配置好了之后，master那台机子有VIP，backup没有，这是正常的，因为master没有down掉
写一个小代码，让keepalived和nginx关联起来，在master中写
写到配置文件global下面，这个间隔时间要比master组播的间隔时间要长一点
vrrp_script check{
script "/etc/keepalived/script/nginx_check.sh"
interval 2
}
测试：确保nginx是开着的，不然ip飘逸不过去
测试结果：
·
格式一定要标准，脚本写了之后不需要重启
keepalived 配置lvs
master error real-server1 real-server2
在master机子配置 keepalived
并添加一个ip或者一个网卡
其他三台机子需要配置唯一ip
ip a a 192.168.91.134/32 dev lo
当dr要接受消息时候让rs保持静默
在其他三台机子：
[root@real-server1 ~]# ip addr add dev lo 172.16.147.200/32 #在lo接口上绑定VIP [root@real-server1 ~]# echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore #忽略arp广播 [root@real-server1 ~]# echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce #匹配精确ip地址回包
并且下载并启动nginx服务，写好自己要测试的三个页面（每台一个）文章来源：https://www.toymoban.com/news/detail-861575.html
并测试文章来源地址https://www.toymoban.com/news/detail-861575.html
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