LVS + Keepalived群集
文章目录
- LVS + Keepalived
-
- 1 Keepalived及其工作原理
- 2 一个健康的集群的特点
- 3 Keepalived常见问题脑裂
-
- 3.1 原因
- 3.2 预防
- 3.3 配置
- 4 部署keepalived
-
- 4.1 部署192.168.146.20
- 4.2 部署192.168.146.30
- 5 LVS+Keepalived高可用群集
-
- 5.1 部署192.168.146.50(nginx)
- 5.2 部署192.168.146.60（nginx）
- 5.3 部署192.168.146.20 主
- 5.4 部署192.168.146.30 从
- 5.5 测试访问
LVS + Keepalived
1 Keepalived及其工作原理
keepalived高可用应用（健康检查，故障切换）
底层基于VRRP协议实现的高可用
由优先级决定服务器的主备角色，Master服务器上会生成vip，客户端会把访问发送给vip，由Master服务器接收用户的请求，Master服务器会定期给Backup服务器发送VRRP报文，来告知Master服务器状态正常
当Backup在超时时间内没有收到VRRP报文则会认为Master异常，此时会通过ip命令生成VIP，接替Master的工作接收用户请求
2 一个健康的集群的特点
1.负载均衡
2.健康检查：探针 （心跳消息-ping， tcp端口检查-三次握手，http url检查-返回码）
3.故障切换
3 Keepalived常见问题脑裂
3.1 原因
Master一直发送心跳消息给backup主机
如果中间的链路突然断掉，backup主机将无法收到master主机发送过来的心跳消息（也就是vrrp报文），backup这时候会立即抢占master的工作
但其实这时候的master是正常工作的，此时就会出现脑裂的现象
3.2 预防
1.使用shell脚本对这两个主机之间的连通性进行监测，如果发现有问题，就会立即关闭keepalived服务来防止脑裂的产生
2.增加一条链路作为备用链路，即使主链路挂掉了，备用链路也会顶上来，master主机可以继续给backup主机发送心跳消息
3.监控软件的方法，这边主要是采用的zabbix来监控的，主要就是创建监控项，创建触发器来测试关闭keepalived服务
3.3 配置
cd /etc/keepalived/
cp keepalived.conf keepalived.conf.bak
vim keepalived.conf
......
global_defs { #定义全局参数
--10行--修改，邮件服务指向本地
smtp_server 127.0.0.1
--12行--修改，指定服务器（路由器）的名称，主备服务器名称须不同，主为LVS_01，备为LVS_02
router_id LVS_01
--14行--注释掉，取消严格遵守VRRP协议功能，否则VIP无法被连接
#vrrp_strict
}
vrrp_instance VI_1 { #定义VRRP热备实例参数
--20行--修改，指定热备状态，主为MASTER，备为BACKUP
state MASTER
--21行--修改，指定承载vip地址的物理接口
interface ens33
--22行--修改，指定虚拟路由器的ID号，每个热备组保持一致
virtual_router_id 10
#nopreempt #如果设置非抢占模式，两个节点state必须为bakcup，并加上配置 nopreempt
--23行--修改，指定优先级，数值越大优先级越高，这里设置主为100，备为90
priority 100
advert_int 1 #通告间隔秒数(心跳频率)
authentication { #定义认证信息,每个热备组保持一致
auth_type PASS #认证类型
--27行--修改，指定验证密码，主备服务器保持一致
auth_pass abc123
}
virtual_ipaddress { #指定群集vip地址
192.168.80.188
}
}
--36行--修改，指定虚拟服务器地址(VIP)、端口，定义虚拟服务器和Web服务器池参数
virtual_server 192.168.80.188 80 {
delay_loop 6 #健康检查的间隔时间(秒)
lb_algo rr #指定调度算法，轮询(rr)
--39行--修改，指定群集工作模式，直接路由(DR)
lb_kind DR
persistence_timeout 0 #连接保持时间(秒)
protocol TCP #应用服务采用的是 TCP协议
--43行--修改，指定第一个Web节点的地址、端口
real_server 192.168.80.12 80 {
weight 1 #节点的权重
--45行--删除，添加以下健康检查方式
TCP_CHECK {
connect_port 80 #添加检查的目标端口
connect_timeout 3 #添加连接超时(秒)
nb_get_retry 3 #添加重试次数
delay_before_retry 3 #添加重试间隔
}
}
real_server 192.168.80.13 80 { #添加第二个 Web节点的地址、端口
weight 1
TCP_CHECK {
connect_port 80
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
##删除后面多余的配置##
}
systemctl start keepalived
ip addr #查看虚拟网卡vip
4 部署keepalived
192.168.146.20（主）
192.168.146.30（备）
4.1 部署192.168.146.20
systemctl stop firewalld
setenforce 0
yum -y install keepalived.x86_64
cd /etc/keepalived/
cp keepalived.conf keepalived.conf.bak
vim keepalived.conf
global_defs {
notification_email {
[email protected]
[email protected]
[email protected]
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_01
}
vrrp_instance VI_1 {
state MASTER
interface ens33
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.146.188
}
}
systemctl start keepalived.service
systemctl enable keepalived.service
可以将主的配置文件复制到从后进行修改
scp keepalived.conf 192.168.146.30`pwd`
4.2 部署192.168.146.30
systemctl stop firewalld
setenforce 0
yum -y install keepalived.x86_64
cd /etc/keepalived/
cp keepalived.conf keepalived.conf.bak
vim keepalived.conf ##此文件已经从主服务器上复制过来了
global_defs {
notification_email {
[email protected]
[email protected]
[email protected]
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_02
}
vrrp_instance VI_1 {
state BACKUP
interface ens33
virtual_router_id 51
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.146.188
}
}
systemctl start keepalived.service
systemctl enable keepalived.service
5 LVS+Keepalived高可用群集
192.168.146.20 主
192.168.146.30 备
192.168.146.50 nginx
192.168.146.60 nginx
5.1 部署192.168.146.50(nginx)
把nginx.repo的包拖到/etc/yum.repos.d
yum -y install nginx
编辑网页文件
cd /usr/share/nginx/html/
vim test.html
this is nginx1 test web!
添加vip，在lo上面
cd /etc/sysconfig/network-scripts/
cp ifcfg-lo ifcfg-lo:0
vim ifcfg-lo:0
DEVICE=lo:0
IPADDR=192.168.146.188
NETMASK=255.255.255.255
ONBOOT=yes
修改内核参数
vim /etc/sysctl.conf
net.ipv4.conf.lo.arp_ignore = 1
net.ipv4.conf.lo.arp_announce = 2
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
指定路由
route add -host 192.168.146.188 dev lo:0
5.2 部署192.168.146.60（nginx）
把nginx.repo的包拖到/etc/yum.repos.d
yum -y install nginx
添加网页文件
cd /usr/share/nginx/html/
vim test.html
this is nginx2 test web!
添加vip，在lo上面
cd /etc/sysconfig/network-scripts/
cp ifcfg-lo ifcfg-lo:0
vim ifcfg-lo:0
DEVICE=lo:0
IPADDR=192.168.146.188
NETMASK=255.255.255.255
ONBOOT=yes
修改内核参数
vim /etc/sysctl.conf
net.ipv4.conf.lo.arp_ignore = 1
net.ipv4.conf.lo.arp_announce = 2
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
指定路由
route add -host 192.168.146.188 dev lo:0
5.3 部署192.168.146.20 主
systemctl stop firewalld.service
setenforce 0
yum -y install keepalived ipvsadm
modprobe ip_vs
ipvsadm-save > /etc/sysconfig/ipvsadm
systemctl start ipvsadm
cd /etc/keepalived/
cp keepalived.conf keepalived.conf.bak
vim keepalived.conf
global_defs {
notification_email {
[email protected]
[email protected]
[email protected]
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_01
}
vrrp_instance VI_1 {
state MASTER
interface ens33
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.146.188
}
}
virtual_server 192.168.146.188 80 {
delay_loop 6
lb_algo rr
lb_kind DR
persistence_timeout 0
protocol TCP
real_server 192.168.146.50 80 {
weight 1
TCP_CHECK {
connect_port 80
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
real_server 192.168.146.60 80 {
weight 1
TCP_CHECK {
connect_port 80
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}
#可以把主的配置文件复制到从中去
scp keepalived.conf 192.168.146.30:`pwd`
设置内核参数
vim /etc/sysctl.conf
net.ipv4.ip_forward = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
net.ipv4.conf.ens33.send_redirects = 0
sysctl -p
systemctl start keepalived
5.4 部署192.168.146.30 从
systemctl stop firewalld.service
setenforce 0
yum -y install keepalived ipvsadm
modprobe ip_vs
ipvsadm-save > /etc/sysconfig/ipvsadm
systemctl start ipvsadm
keepalived的配置文件已经从主复制过来了
vim keepalived.conf
global_defs {
notification_email {
[email protected]
[email protected]
[email protected]
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_02
}
vrrp_instance VI_1 {
state BACKUP
interface ens33
virtual_router_id 51
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.146.188
}
}
virtual_server 192.168.146.188 80 {
delay_loop 6
lb_algo rr
lb_kind DR
persistence_timeout 0
protocol TCP
real_server 192.168.146.50 80 {
weight 1
TCP_CHECK {
connect_port 80
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
real_server 192.168.146.60 80 {
weight 1
TCP_CHECK {
connect_port 80
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}
设置内核参数
vim /etc/sysctl.conf
net.ipv4.ip_forward = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
net.ipv4.conf.ens33.send_redirects = 0
sysctl -p
systemctl start keepalived
5.5 测试访问
