Keepalived知识点整理
高可用集群 keeaplived
高可用集群
集群类型
-
LB:load Balance 负载均衡
LVS/HAProxy/nginx(http/upstream,stream/upstrream)
-
HA:Hight Availibility 高可用集群
数据库,Redis
-
SPoF:Snigle Point of Fallure,解决单点故障
HPC:High Performabce Computing高性能集群
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可认可的协议或契约)
A=MTBF/(MTBF/MTTR)
99.9%:(60*24*30)*(1-0.9995)=21.6分钟 #一般按一个月停机时间统计
系统故障
硬件故障:设计缺陷,wear out(损耗),非认为不可抗因素
软件故障:设计缺陷,bug
实现高可用
提升系统高性能的解决方案:降低MTTR-Mean Time To Repair(平均故障时间)
解决方案:家里冗余机制
- active/passive 主/备
- active/active 主/主
- active->HEARTBEAT->passive
- active<->HEATBEAT<->active
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
VRRP相关术语
- 虚拟路由器:Virtual Router
- 虚拟路由器标识:VIRD(0.255),唯一标识虚拟路由器
- VIP:Virtual IP
- VMAV:Virtual MAC
- 物理路由器
- master:主设备
- backup:备用设备
- priority:优先级
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
- MDS
工作模式:
- 主/从:单虚拟路由
- 主/主:主/备(虚拟路由器1),备/主(虚拟路由器2)
keepalived简介
Keepalived本质就是为ipvs服务的,它也不需要共享存储。IPVS其实就是一些规则,Keepalived主要的任务就是去调用ipvsadm命令,来生成规则,并自动实现将用户需要访问的地址转移到可用LVS节点实现
主要目的就是它自身启动为一个服务,它工作在多个LVS主机节点上,当前活动的节点叫做Master备用节点叫做Backup,Master会不停的向Backup节点通告自己的心跳,这种通告是基于VRRP协议的。Backup节点一旦接收不到Master的通告信息,它就会把LVS的VIP拿过来,并且把ipvs的规则也拿过来,在自己身上生效,从而替代Master节点
总的来说keepalived是vrrp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
keeplived架构
用户空间核心组件:
- vrrp stack:VIP消息通告
- checkers:检测real server
- system call:实现vrrp协议状态转换时调用脚本的功能
- SMTP:邮件组件
- IPVS wrapper:生成IPVS规则
- Netlink Reflctor:网络接口
- WatchDog:监控进程
控制组件:提供keepalived.conf的解析器,完成keepalived配置
IO复用器:针对网络目的的优化的自己的线程抽象
内存管理组件:为某些通用的内存管理功能(例如分配,重新分配,发布等)提供网络访问权限
配置文件组成部分
配置文件:/etc/keepalived/keepalived.conf
配置文件的组成:
-
GLOBAL CONFIGURATION
Global definitions:定义邮件配置,route_id,vrrp配置,多播地址等
-
VRRP CONFIGURATION
VRRP instance(s):定义每个vrrp虚拟路由器
-
LVS CONFIGURATION
Virtual server group(s)
Virtual server(s):LVS集群的VS和RS
配置文件主要部分的解释说明:
! Configuration File for keepalived
#全局配置
global_defs {
notification_email {
666688889@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
}
notification_email_from keepalived@lanjinli.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.lanjinli.org #每个keepalived主机唯一标识,建议使用当前主机名,但节点多不影响
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,启用此配置后,如果在无VIP地址或配置了单播邻居,或在VRRP版本2中有IPV6地址的建议不适应此配置
vrrp_garp_interval 0 #报文发送延迟
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 BACKUP #指定是主(MASTER)还是备(BACKUP)
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不再同一个网卡
virtual_router_id 100 #每个虚拟路由器唯一标识,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 80 #当前物理节点在此虚拟路由器的优先级,范围:1-255,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,默认为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)
auth_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
172.25.254.100/24 dev eth0 label eth0:1
}
}
环境配置
四台机器
注: 四台机器都关闭了防火墙和SELinux
ka1
eth0 172.25.254.10
安装keepalived
关闭了防火墙和SELinux
[root@ka1 ~]# 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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:92:51:bd brd ff:ff:ff:ff:ff:ff
inet 172.25.254.10/24 brd 172.25.254.255 scope global noprefixroute eth0
valid_lft forever preferred_lft forever
inet6 fe80::435f:2ba:94d2:582/64 scope link tentative noprefixroute dadfailed
valid_lft forever preferred_lft forever
inet6 fe80::4da5:5424:6c11:6bc/64 scope link noprefixroute
valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN group default qlen 1000
link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
#安装keepalived
[root@ka1 ~]# yum install keepalived -y
[root@ka1 ~]# systemctl stop firewalld.service
[root@ka1 ~]# setenforce 0
ka2
eth0 172.25.254.20
安装keepalived
关闭了防火墙和SELinux
[root@ka2 ~]# 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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:68:ef:05 brd ff:ff:ff:ff:ff:ff
inet 172.25.254.20/24 brd 172.25.254.255 scope global noprefixroute eth0
valid_lft forever preferred_lft forever
inet 172.25.254.100/24 scope global secondary eth0:1
valid_lft forever preferred_lft forever
inet6 fe80::435f:2ba:94d2:582/64 scope link noprefixroute
valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN group default qlen 1000
link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
[root@ka2 ~]# yum install keepalived -y
[root@ka2 ~]# systemctl stop firewalld.service
[root@ka2 ~]# setenforce 0
realserver1
eth0 172.25.254.110
下载了httpd
[root@realserver1 ~]# 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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:54:22:6a brd ff:ff:ff:ff:ff:ff
inet 172.25.254.110/24 brd 172.25.254.255 scope global noprefixroute eth0
valid_lft forever preferred_lft forever
inet6 fe80::4da5:5424:6c11:6bc/64 scope link tentative noprefixroute dadfailed
valid_lft forever preferred_lft forever
inet6 fe80::435f:2ba:94d2:582/64 scope link tentative noprefixroute dadfailed
valid_lft forever preferred_lft forever
inet6 fe80::d318:4046:600c:390c/64 scope link noprefixroute
valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN group default qlen 1000
link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
[root@realserver1 ~]# yum install httpd -y
#配置httpd
[root@realserver1 ~]# echo hehehe > /var/www/html/index.html
#启动并设置开机自启
[root@realserver1 ~]# systemctl enable --now httpd
[root@realserver1 ~]# systemctl stop firewalld.service
[root@realserver1 ~]# setenforce 0
realserver2
eth0 172.25.254.120
下载了httpd
[root@realserver2 ~]# 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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:69:b5:ed brd ff:ff:ff:ff:ff:ff
inet 172.25.254.120/24 brd 172.25.254.255 scope global noprefixroute eth0
valid_lft forever preferred_lft forever
inet6 fe80::4da5:5424:6c11:6bc/64 scope link tentative noprefixroute dadfailed
valid_lft forever preferred_lft forever
inet6 fe80::435f:2ba:94d2:582/64 scope link tentative noprefixroute dadfailed
valid_lft forever preferred_lft forever
inet6 fe80::d318:4046:600c:390c/64 scope link tentative noprefixroute dadfailed
valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN group default qlen 1000
link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
[root@realserver2 ~]# yum install httpd -y
#配置httpd
[root@realserver2 ~]# echo hehehe > /var/www/html/index.html
#启动并设置开机自启
[root@realserver2 ~]# systemctl enable --now httpd
[root@realserver2 ~]# systemctl stop firewalld.service
[root@realserver2 ~]# setenforce 0
实验1:
默认为抢占模式的实验,当一个主机上的VIP下线过后,另一台主机就获取VIP
ka1的keepalived配置文件
[root@ka1 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
6668889@qq.com
}
notification_email_from keepalived.lanjinli.org
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id ka1.lanjinli.org
vrrp_skip_check_adv_addr
#vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
vrrp_mcast_group4 224.0.0.18
}
vrrp_instance VI_1 {
state MASTER
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
}
}
......
#重启服务
[root@ka1 ~]# systemctl restart keepalived.service
ka2的keepalived配置文件
[root@ka2 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
6668889@qq.com
}
notification_email_from keepalived@lanjinli.org
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id ka2.lanjinli.org
vrrp_skip_check_adv_addr
#vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
vrrp_mcast_group4 224.0.0.18
}
vrrp_instance VI_1 {
state BACKUP
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
}
}
......
#重启服务
[root@ka2 ~]# systemctl restart keepalived.service
检测:
#可以通过抓包查看数据的流向,抓的是发往组播上的包
[root@realserver1 ~]# tcpdump -i eth0 -nn host 224.0.0.18
#由于ka2的权重比较高,所以ka2包含的有VIP,tcp包从20发往224.0.0.18
[root@ka2 ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.25.254.20 netmask 255.255.255.0 broadcast 172.25.254.255
inet6 fe80::435f:2ba:94d2:582 prefixlen 64 scopeid 0x20<link>
inet6 fe80::4da5:5424:6c11:6bc prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:68:ef:05 txqueuelen 1000 (Ethernet)
RX packets 30159 bytes 4025655 (3.8 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 43306 bytes 3358755 (3.2 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
eth0:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.25.254.100 netmask 255.255.255.0 broadcast 0.0.0.0
ether 00:0c:29:68:ef:05 txqueuelen 1000 (Ethernet)
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 1000 (Local Loopback)
RX packets 1450 bytes 111001 (108.3 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 1450 bytes 111001 (108.3 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255
ether 52:54:00:6b:1d:b7 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[root@ka2 ~]#
#如果关闭ka2上的keepalived服务,则ka1上加入了VIP,tcp包从10发往224.0.0.18
[root@ka1 ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.25.254.10 netmask 255.255.255.0 broadcast 172.25.254.255
inet6 fe80::435f:2ba:94d2:582 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:92:51:bd txqueuelen 1000 (Ethernet)
RX packets 38254 bytes 5109536 (4.8 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 41709 bytes 3230481 (3.0 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
eth0:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.25.254.100 netmask 255.255.255.0 broadcast 0.0.0.0
ether 00:0c:29:92:51:bd txqueuelen 1000 (Ethernet)
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 1000 (Local Loopback)
RX packets 1535 bytes 117492 (114.7 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 1535 bytes 117492 (114.7 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255
ether 52:54:00:6b:1d:b7 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[root@ka1 ~]#
实验2
日志和子配置文件
独立日志:
#日志修改
[root@ka1 ~]# cat /etc/keepalived/keepalived.conf
...
global_defs {
notification_email {
666688889@qq.com
}
notification_email_from keepalived@lanjinli.org
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id ka1.lanjinli.org
vrrp_skip_check_adv_addr
#vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
vrrp_mcast_group4 224.0.0.18
}
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
}
}
virtual_server 192.168.200.100 443 {
...
[root@ka1 ~]# cat /etc/sysconfig/keepalived
# Options for keepalived. See `keepalived --help' output and keepalived(8) and
# keepalived.conf(5) man pages for a list of all options. Here are the most
# common ones :
#
# --vrrp -P Only run with VRRP subsystem.
# --check -C Only run with Health-checker subsystem.
# --dont-release-vrrp -V Dont remove VRRP VIPs & VROUTEs on daemon stop.
# --dont-release-ipvs -I Dont remove IPVS topology on daemon stop.
# --dump-conf -d Dump the configuration data.
# --log-detail -D Detailed log messages.
# --log-facility -S 0-7 Set local syslog facility (default=LOG_DAEMON)
#
KEEPALIVED_OPTIONS="-D -S 6"
[root@ka1 ~]#
#修改日志文件
[root@ka1 ~]# vim /etc/rsyslog.conf
...
# Save boot messages also to boot.log
local7.* /var/log/boot.log
local6.* /var/log/keepalived.log
...
#重启服务
[root@ka1 ~]# systemctl restart keepalived.service #使格式文件生效
[root@ka1 ~]# systemctl restart rsyslog.service #使定向文件生效
[root@ka1 ~]# systemctl restart keepalived.service #使生成日志文件
#查看是否生成日志文件
[root@ka1 ~]# ll /var/log/keepalived.log
-rw-------. 1 root root 29956 Aug 12 02:14 /var/log/keepalived.log
[root@ka1 ~]#
子配置文件
当生产环境复杂时, /etc/keepalived/keepalived.conf 文件中内容过多,不易管理
这时候可以将不同集群的配置,比如不同集群的VIP配置放在独立的子配置文件中利用include指令可以实现包含子配置文件
格式:
include pathfile
#编辑主配置文件
[root@ka1 ~]# cat /etc/keepalived/keepalived.conf
...
vrrp_gna_interval 0
vrrp_mcast_group4 224.0.0.18
}
#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
# }
#}
#定义子配置文件目录
include "/etc/keepalived/conf.d/*.conf"
virtual_server 192.168.200.100 443 {
...
#创建子配置文件目录
[root@ka1 ~]# mkdir -p /etc/keepalived/conf.d
[root@ka1 ~]# vim /etc/keepalived/conf.d/172.25.254.100.conf
[root@ka1 ~]# cat /etc/keepalived/conf.d/172.25.254.100.conf
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
}
}
[root@ka1 ~]#
#重启keepalived
[root@ka1 ~]# systemctl restart keepalived.service
#查看是否运行成功获得了vip172.25.254.100,注意权重的问题
[root@ka1 ~]# 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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:92:51:bd brd ff:ff:ff:ff:ff:ff
inet 172.25.254.10/24 brd 172.25.254.255 scope global noprefixroute eth0
valid_lft forever preferred_lft forever
inet 172.25.254.100/24 scope global secondary eth0:1
valid_lft forever preferred_lft forever
inet6 fe80::435f:2ba:94d2:582/64 scope link tentative noprefixroute dadfailed
valid_lft forever preferred_lft forever
inet6 fe80::4da5:5424:6c11:6bc/64 scope link noprefixroute
valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN group default qlen 1000
link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
[root@ka1 ~]#
抢占模式和非抢占模式
非抢占模式(nopreempt)
在安装了keepalived过后,默认的是使用的是抢占模式,即当高权重高优先级主机在恢复在线后,会抢占优先级低的主机的master角色,这样会使vip在主机中来回切换,造成网络抖动,建议设置成非抢占模式nopreempt,即高优先级主机恢复后,并不会抢占低优先级主机的master角色,非抢占模式下,如果原主机down机,vip迁址新主机,后续也会发生down时,仍会将vip迁回原主机
注: 要关闭vip抢占,必须要将各个keepalived服务器state配置成BACKUP
#可以通过抓包查看数据的流向,抓的是发往组播上的包
[root@realserver1 ~]# tcpdump -i eth0 -nn host 224.0.0.18
#ka1编写keepalived配置文件
[root@ka1 ~]# cat /etc/keepalived/keepalived.conf
...
global_defs {
notification_email {
6668889@qq.com
}
notification_email_from keepalived.lanjinli.org
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id ka1.lanjinli.org
vrrp_skip_check_adv_addr
#vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
vrrp_mcast_group4 224.0.0.18
}
vrrp_instance VI_1 {
#state MASTER
state BACKUP
interface eth0
virtual_router_id 100
priority 80 #优先级高
advert_int 1
nopreempt #非抢占模式
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.25.254.100/24 dev eth0 label eth0:1
}
}
...
#ka2编写keepalived配置文件
[root@ka2 ~]# cat /etc/keepalived/keepalived.conf
...
global_defs {
notification_email {
6668889@qq.com
}
notification_email_from keepalived@lanjinli.org
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id ka2.lanjinli.org
vrrp_skip_check_adv_addr
#vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
vrrp_mcast_group4 224.0.0.18
}
vrrp_instance VI_1 {