前面的lvs虽然已经配置成功也实现了负载均衡,但是我们测试的时候发现,当某台real server把nginx进程停掉,那么director照样会把请求转发过去,这样就造成了某些请求不正常。所以需要有一种机制用来检测real server的状态,这就是keepalived。它的作用除了可以检测rs状态外,还可以检测备用director的状态,也就是说keepalived可以实现ha集群的功能,当然了也需要一台备用director。
备用director也需要安装一下keepalived软件、ipvsadm;
keepalived调用lvs来实现自己的规则;
yum install -y keepalived ipvsadm
环境搭建工作:
主director 192.168.11.30 eth1网卡
从director 192.168.11.40 eth1网卡
real server1: 192.168.11.100 eth0网卡
real server2: 192.168.11.101 eth0网卡
用来curl测试的linux主机 192.168.11.0 网段即可;
主dr和备用dr都需要安装keepalived,ipvsadm;
两台rs安装nginx;
安装好后,主director的配置文件
vim /etc/keepalived/keepalived.conf //加入如下:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
|
vrrp_instance VI_1 { state MASTER #备用服务器上为 BACKUP
interface eth1
virtual_router_id 51
priority 100 #优先级,数值越大优先级越高;备用服务器上为90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.11.110
}
} virtual_server 192.168.11.110 80 { delay_loop 6 #(每隔6秒查询realserver状态,是否存活)
lb_algo wlc #(轮询算法)
lb_kind DR #(Direct Route)
persistence_timeout 0 #(同一IP的连接多少秒内被分配到同一台realserver,0表示不连接)
protocol TCP #(用TCP协议检查realserver状态)
real_server 192.168.11.100 80 {
weight 100 #(权重)
TCP_CHECK {
connect_timeout 10 #(10秒无响应超时)
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
real_server 192.168.11.101 80 { weight 100
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
} |
从director的配置文件只需要修改下面两项:
state MASTER -> state BACKUP
priority 100 -> priority 90
配置完keepalived后,需要开启端口转发(主从dr都要做):
echo 1 > /proc/sys/net/ipv4/ip_forward
然后,两个rs上执行 /usr/local/sbin/lvs_dr_rs.sh 脚本,启动nginx服务
1
|
# /etc/init.d/nginx start |
最后,两个director上启动keepalived服务(先主后从):
1
|
# /etc/init.d/keepalived start |
另外,需要注意的是,启动keepalived服务会自动生成vip和ipvsadm规则.
使用命令#ip addr 查看dr的虚拟ip地址;直接使用ifconfig不显示虚拟ip;
1
2
3
4
5
6
7
8
|
[root@dr1 keepalived] # ip addr
eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000 link /ether 00:0c:29:97:c3:f6 brd ff:ff:ff:ff:ff:ff
inet 192.168.11.30 /24 brd 192.168.11.255 scope global eth1
inet 192.168.11.110 /32 scope global eth1
inet6 fe80::20c:29ff:fe97:c3f6 /64 scope link
valid_lft forever preferred_lft forever
|
在其他机器curl测试,请求rs1和rs2次数相当;
1
2
3
4
5
6
7
8
|
[root@localhost ~] # curl 192.168.11.110
rs1rs1 [root@localhost ~] # curl 192.168.11.110
rs2rs2 [root@localhost ~] # curl 192.168.11.110
rs1rs1 [root@localhost ~] # curl 192.168.11.110
rs2rs2 |
rs2上面stop nginx,然后curl测试,发现所有的请求都到rs1上面了;
日志里面也会记录remove rs2;日志文件:/var/log/messages
1
|
[root@rs2 ~] # /etc/init.d/nginx stop
|
1
2
3
4
5
6
7
8
|
[root@localhost ~] # curl 192.168.11.110
rs1rs1 [root@localhost ~] # curl 192.168.11.110
rs1rs1 [root@localhost ~] # curl 192.168.11.110
rs1rs1 [root@localhost ~] # curl 192.168.11.110
rs1rs1 |
1
2
3
|
[root@dr1 ~] # tail -2 /var/log/messages
Jun 9 23:27:19 localhost Keepalived_healthcheckers[1572]: TCP connection to [192.168.11.101]:80 failed !!! Jun 9 23:27:19 localhost Keepalived_healthcheckers[1572]: Removing service [192.168.11.101]:80 from VS [192.168.11.110]:80 |
rs2启动nginx,日志文件记录adding rs2;curl测试,发现请求平均分配到rs1和rs2上面了;
1
|
[root@rs2 ~] # /etc/init.d/nginx start
|
1
2
3
|
[root@dr1 ~] # tail -2 /var/log/messages
Jun 9 23:31:38 localhost Keepalived_healthcheckers[1572]: TCP connection to [192.168.11.101]:80 success. Jun 9 23:31:38 localhost Keepalived_healthcheckers[1572]: Adding service [192.168.11.101]:80 to VS [192.168.11.110]:80 |
1
2
3
4
5
6
7
8
|
[root@localhost ~] # curl 192.168.11.110
rs1rs1 [root@localhost ~] # curl 192.168.11.110
rs2rs2 [root@localhost ~] # curl 192.168.11.110
rs1rs1 [root@localhost ~] # curl 192.168.11.110
rs2rs2 |
加入dr2 备用dircetor机器;
主上停止keepalive服务;stop之后,在从上ip addr查看绑定虚拟ip,说明从接管了服务;切换速度很快;
主上启动keepalived服务后,主绑定虚拟ip,接管服务;
1
2
3
4
5
|
[root@dr2 keepalived] # ip addr
eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000 link /ether 00:0c:29:af:73:3f brd ff:ff:ff:ff:ff:ff
inet 192.168.11.40 /24 brd 192.168.11.255 scope global eth1
inet 192.168.11.110 /32 scope global eth1
|
nc命令可以扫描端口是否打开:
在其他机器上扫描,11.100 和11.101,11.110的80端口是否打开;
#nc -z -w2 192.168.11.110 80
1
2
3
4
5
6
|
[root@localhost ~] # nc -z -w2 192.168.11.100 80
Connection to 192.168.11.100 80 port [tcp /http ] succeeded!
[root@localhost ~] # nc -z -w2 192.168.11.101 80
Connection to 192.168.11.101 80 port [tcp /http ] succeeded!
[root@localhost ~] # nc -z -w2 192.168.11.110 80
Connection to 192.168.11.110 80 port [tcp /http ] succeeded!
|
本文转自 模范生 51CTO博客,原文链接:http://blog.51cto.com/mofansheng/1660329,如需转载请自行联系原作者