一 . 高可用集群
1.1 集群类型
LB ： Load Balance 负载均衡
LVS/HAProxy/nginx （ http/upstream, stream/upstream ）
HA ： High Availability 高可用集群
数据库、 Redis
SPoF: Single Point of Failure ，解决单点故障
HPC ： High Performance Computing 高性能集群
1.2 系统可用性
SLA ： Service-Level Agreement 服务等级协议（提供服务的企业与客户之间就服务的品质、水准、性能
等方面所达成的双方共同认可的协议或契约）
A = MTBF / (MTBF+MTTR ）
指标 ： 99.9%, 99.99%, 99.999%,99.9999%
1.3 系统故障
硬件故障：设计缺陷、 wear out （损耗）、非人为不可抗拒因素
软件故障：设计缺陷 bug
1.4 实现高可用
提升系统高用性的解决方案：降低 MTTR- Mean Time To Repair( 平均故障时间 )
解决方案：建立冗余机制
active/passive 主 / 备
active/active 双主
active --> HEARTBEAT --> passive
active <--> HEARTBEAT <--> active
1.5.VRRP ： Virtual Router Redundancy Protocol
虚拟路由冗余协议 , 解决静态网关单点风险
物理层 : 路由器、三层交换机
软件层 :keepalived
1.5.1 VRRP 相关术语
虚拟路由器： Virtual Router
虚拟路由器标识： VRID(0-255) ，唯一标识虚拟路由器
VIP ： Virtual IP
VMAC ： Virutal MAC (00-00-5e-00-01-VRID)
物理路由器：
master ：主设备
backup ：备用设备
priority ：优先级
1.5.2 VRRP 相关技术
通告：心跳，优先级等；周期性
工作方式：抢占式，非抢占式
安全认证：
无认证
简单字符认证：预共享密钥
MD5
工作模式：
主 / 备：单虚拟路由器
主 / 主：主 / 备（虚拟路由器 1 ），备 / 主（虚拟路由器 2 ）
keepalived部署
keepalived 简介
vrrp 协议的软件实现，原生设计目的为了高可用 ipvs服务
功能：
基于vrrp协议完成地址流动
为vip地址所在的节点生成ipvs规则(在配置文件中预先定义)
为ipvs集群的各RS做健康状态检测
基于脚本调用接口完成脚本中定义的功能，进而影响集群事务，以此支持nginx、haproxy等服务
Keepalived 环境准备
Keepalived 相关文件
软件包名：keepalived
主程序文件：/usr/sbin/keepalived
主配置文件：/etc/keepalived/keepalived.conf
配置文件示例：/usr/share/doc/keepalived/
Unit File：/lib/systemd/system/keepalived.service
Unit File的环境配置文件：/etc/sysconfig/keepalived
Keepalived环境配置
ka1的IP配置
[root@localhost network-scripts]# vmset.sh eth0 172.25.254.10 ka1.timinglee.org
ka2的IP配置
[root@localhost ~]# vmset.sh eth0 172.25.254.20 ka2.timinglee.org
server1的IP配置
[root@localhost ~]# vmset.sh eth0 172.25.254.110 server1.timinglee.org
server2的IP配置
[root@localhost ~]# vmset.sh eth0 172.25.254.120 server2.timinglee.org
server1和server2都安装httpd服务
[root@server1 ~]# echo 172.25.254.110 > /var/www/html/index.html
[root@server1 ~]# systemctl enable --now httpd
Created symlink from /etc/systemd/system/multi-user.target.wants/httpd.service to /usr/lib/systemd/system/httpd.service.
[root@server2 ~]# echo 172.25.254.120 > /var/www/html/index.html
[root@server2 ~]# systemctl enable --now httpd
Created symlink from /etc/systemd/system/multi-user.target.wants/httpd.service to /usr/lib/systemd/system/httpd.service.
ka1上测试
keepalived虚拟路由配置
ka1和ka2都安装keepalived
[root@ka1 ~]# yum install keepalived -y
[root@ka1 ~]# man 5 keepalived.conf---查看帮助
[root@ka1 ~]# vim /etc/keepalived/keepalived.conf --配置文件
全局配置
! Configuration File for keepalived
global_defs {
notification_email {
594233887@qq.com #keepalived 发生故障切换时邮件发送的目标邮箱，可以按行区分写多个
timiniglee-zln@163.com
}
notification_email_from keepalived@KA1.timinglee.org #发邮件的地址
smtp_server 127.0.0.1 #邮件服务器地址
smtp_connect_timeout 30 #邮件服务器连接timeout
router_id KA1.timinglee.org #每个keepalived主机唯一标识建议使用当前主机名，但多节点重名不影响
vrrp_skip_check_adv_addr #对所有通告报文都检查，会比较消耗性能，启用此配置后，如果收到的通告报文和上一个报文是同 一个路由器，则跳过检查，默认值为全检查
vrrp_strict #严格遵循vrrp协议
#启用此项后以下状况将无法启动服务:
#1.无VIP地址
#2.配置了单播邻居
#3.在VRRP版本2中有IPv6地址
#建议不加此项配置
vrrp_garp_interval 0 #报文发送延迟，0表示不延迟
vrrp_gna_interval 0 #消息发送延迟
vrrp_mcast_group4 224.0.0.18 #指定组播IP地址范围：
}
配置虚拟路由器
vrrp_instance VI_1 {
state MASTER
interface eth0 #绑定为当前虚拟路由器使用的物理接口，如：eth0,可以和VIP不在一个网卡
virtual_router_id 51 #每个虚拟路由器惟一标识,范围：0-255，每个虚拟路由器此值必须唯一
#否则服务无法启动
#同属一个虚拟路由器的多个keepalived节点必须相同
#务必要确认在同一网络中此值必须唯一
priority 100 #当前物理节点在此虚拟路由器的优先级，范围：1-254
#值越大优先级越高,每个keepalived主机节点此值不同
advert_int 1 #vrrp通告的时间间隔，默认1s
authentication { #认证机制
auth_type AH|PASS #AH为IPSEC认证(不推荐),PASS为简单密码(建议使用)
uth_pass 1111 #预共享密钥，仅前8位有效
#同一个虚拟路由器的多个keepalived节点必须一样
}
virtual_ipaddress { #虚拟IP,生产环境可能指定上百个IP地址
<IPADDR>/<MASK> brd <IPADDR> dev <STRING> scope <SCOPE> label <LABEL>
172.25.254.100 #指定VIP，不指定网卡，默认为eth0,注意：不指定/prefix,默认32
172.25.254.101/24 dev eth1
172.25.254.102/24 dev eth2 label eth2:1
}
}
实验实例----虚拟路由器
ka1
[root@ka1 ~]# vim /etc/keepalived/keepalived.conf
ka2
[root@ka2 ~]# vim /etc/keepalived/keepalived.conf
也可复制去配置
[root@ka2 ~]# scp /etc/keepalived/keepalived.conf root@172.25.254.20:/etc/keepalived/keepalived.conf
The authenticity of host '172.25.254.20 (172.25.254.20)' can't be established.
ECDSA key fingerprint is SHA256:mT1nI9LQcSBAxtMowpMdk/qQ/rIPxWexv72aZL+B0o4.
ECDSA key fingerprint is MD5:1e:d3:71:ec:af:6d:76:a2:d5:bf:36:cb:e4:07:00:fd.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '172.25.254.20' (ECDSA) to the list of known hosts.
root@172.25.254.20's password:
keepalived.conf 100% 3598 1.8MB/s 00:00
[root@ka2 ~]# vim /etc/keepalived/keepalived.conf
[root@ka2 ~]# systemctl enable --now keepalived.service
测试
开启通信功能及独立日志
[root@ka1 ~]# vim /etc/sysconfig/keepalived
[root@ka1 ~]#vim /etc/rsyslog.conf
做完这两步后重启
[root@ka1 ~]# systemctl restart keepalived.service
[root@ka1 ~]# systemctl restart rsyslog.service
[root@ka1 ~]# systemctl restart keepalived.service
测试
独立子配置文件
非抢占和延迟抢占
非抢占
延迟抢占
组播变单播
ka1和ka2都要配置
[root@ka1 ~]# vim /etc/keepalived/keepalived.conf
[root@ka2 ~]# vim /etc/keepalived/keepalived.conf
ka1上测试
ka2上测试
通知脚本类型
当前节点成为主节点时触发的脚本
notify_master <STRING>|<QUOTED-STRING>
当前节点转为备节点时触发的脚本
notify_backup <STRING>|<QUOTED-STRING>
当前节点转为"失败"状态时触发的脚本
notify_fault <STRING>|<QUOTED-STRING>
通用格式的通知触发机制，一个脚本可完成以上三种状态的转换时的通知
notify <STRING>|<QUOTED-STRING>
当停止VRRP时触发的脚本
notify_stop <STRING>|<QUOTED-STRING>
脚本的调用方法
在vim /etc/keepalived/keepalived.conf 中 vrrp_instance VI_1 语句块的末尾加下面行
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
邮件通知
ka1和ka2都安装邮箱发送工具
[root@ka1 ~]# yum install mailx -y
[root@ka2 ~]# yum install mailx -y
邮箱配置ka1和ka2都需要配置
[root@ka1 ~]# vim /etc/mail.rc
发送测试邮件
echo hello world | mail -s test **********@qq.com
实现 Keepalived 状态切换的通知脚本
创建通知脚本---ka1和ka2 都配置
[root@ka1 ~]# vim /etc/keepalived/mail.sh
#!/bin/bash
mail_dst="12345678@qq.com"
send_message()
{
mail_sub="$HOSTNAME to be $1 vip move"
mail_meg="`date +%F\ %T`: vrrp move $HOSTNAME chage $1"
echo $mail_meg | mail -s "$mail_sub" $mail_dst
}
case $1 in
master)
send_message master
;;
backup)
send_message backup
;;
fault)
send_message fault
;;
*)
;;
esac
给执行权限
[root@ka1 ~]# chmod +x /etc/keepalived/mail.sh
[root@ka2 ~]# chmod +x /etc/keepalived/mail.sh
ka1和ka2都重启服务
[root@ka1 ~]# systemctl restart keepalived.service
[root@ka2 ~]# systemctl restart keepalived.service
测试
[root@ka1 ~]# /etc/keepalived/mail.sh master
[root@ka2 ~]# /etc/keepalived/mail.sh master
实现 master/master 的 Keepalived 双主架构
#ka1
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 100
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.25.254.100/24 dev eth0 label eth0:1
}
unicast_src_ip 172.25.254.10
unicast_peer {
172.25.254.20
}
track_script {
check_haproxy
}
}
vrrp_instance VI_2 {
state BACKUP #备
interface eth0
virtual_router_id 200
priority 80
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.25.254.200/24 dev eth0 label eth0:2
}
unicast_src_ip 172.25.254.10
unicast_peer {
172.25.254.20
}
}
# ka2
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 100
priority 80
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.25.254.100/24 dev eth0 label eth0:1
}
unicast_src_ip 172.25.254.20
unicast_peer {
172.25.254.10
}
}
vrrp_instance VI_2 {
state MASTER #主
interface eth0
virtual_router_id 200
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.25.254.200/24 dev eth0 label eth0:2
}
unicast_src_ip 172.25.254.20
unicast_peer {
172.25.254.10
}
}
实现IPVS的高可用性
# 在server1\2
[root@server2 ~]# ip a a 172.25.254.100/32 dev lo
[root@server2 ~]# vim /etc/sysctl.d/arp.conf
net.ipv4.conf.all.arp_ignore=1
net.ipv4.conf.all.arp_announce=2
net.ipv4.conf.lo.arp_ignore=1
net.ipv4.conf.lo.arp_announce=2
[root@webserver2 ~]# sysctl --system
# ka1\2
[root@ka1 ~]# yum install ipvsadm -y
[root@ka1 ~]# vim /etc/keepalived/keepalived.conf
virtual_server 172.25.254.100 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
#persistence_timeout 50
protocol TCP
real_server 172.25.254.110 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 2
delay_before_retry 2
}
}
real_server 172.25.254.120 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 2
delay_before_retry 2
}
}
}
[root@ka1 ~]# systemctl restart keepalived.service
[root@ka1 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
[root@ka2 ~]# ipvsadm -A -t 172.255.254.100:80 -s wrr
[root@ka2 ~]# ipvsadm -Ln (有)
[root@ka1 ~]# ipvsadm -Ln (有)
# 测试
[root@ka2 ~]# for i in {1..6}; do curl 172.25.254.100; done
server2 - 172.25.254.120
server1 - 172.25.254.110
server2 - 172.25.254.120
server1 - 172.25.254.110
server2 - 172.25.254.120
server1 - 172.25.254.110
实战案例：实现HAProxy高可用
#ka1、ka2
[root@ka1 ~]# yum install haproxy -y
[root@ka1 ~]# vim /etc/sysctl.conf
net.ipv4.ip_nonlocal_bind = 1
[root@ka1 ~]# sysctl -p
[root@ka1 ~]# vim /etc/haproxy/haproxy.cfg
listen webcluster
bind 172.25.254.100:80
mode http
balance roundrobin
server web1 172.25.254.110:80 check inter 3 fall 2 rise 5
server web2 172.25.254.120:80 check inter 3 fall 2 rise 5
[root@ka1 ~]# sysetemctl enable ---now haproxy
[root@ka1 ~]# netstat -antlupe | grep haproxy
[root@ka1 ~]# curl 172.25.254.100 (不能，和lvs冲突)
[root@ka1 ~]# vim /etc/keepalived/keepalived.conf
注释掉
#virtual_server 172.25.254.100 80 {
[root@ka1 ~]# systemctl restart keepalived.service
#server1、2
[root@server2 ~]# systemctl restart network (删掉lo)
[root@server2 ~]# vim /etc/sysctl.d/arp.conf
net.ipv4.conf.all.arp_ignore=0
net.ipv4.conf.all.arp_announce=0
net.ipv4.conf.lo.arp_ignore=0
net.ipv4.conf.lo.arp_announce=0
[root@server2 ~]# sysctl --system
[root@ka1 ~]# curl 172.25.254.100
[root@ka1 ~]# curl 172.25.254.110
[root@ka1 ~]# curl 172.25.254.120
#现在
在ka1关掉haproxy，则在外面访问不了172.25.254.100，解决这个问题
# 在ka1
[root@ka1 ~]# vim /etc/keepalived/test.sh
#!/bin/bash
killall -0 haproxy
[root@ka1 ~]# sh /etc/keepalived/test.sh
[root@ka1 ~]# echo $?
[root@ka1 ~]# vim /etc/keepalived/keepalived.conf
vrrp_script check_haproxy {
script "/etc/keepalived/test.sh"
interval 1
weight -30
fall 2
rise 2
timeout 2
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 100
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.25.254.100/24 dev eth0 label eth0:1
}
unicast_src_ip 172.25.254.10
unicast_peer {
172.25.254.20
}
track_script {
check_haproxy
}
}
[root@ka1 ~]# systemctl restart keepalived.service
# 测试 关掉ka1的haproxy，也能一直访问
[root@ka1 ~]# systemctl stop haproxy.service
[root@ka1 ~]# systemctl start haproxy.service
[root@ka2 ~]# while true; do curl 172.25.254.100; done