配置Keepalived单实例高可用LVS集群
本篇主要演示通过Keepalived配置管理LVS集群，并对后端RealServer进行健康状态检测（应用层检测），具体工作原理可以见上一篇博客《Keepalived学习总结》。
实验要求 ==> 将两台前端调度器node1和node2配置为一组VRRP示例（即单实例Keepalived），VIP是192.168.10.7。node1和node2根据请求报文的目标IP和目标PORT，按照一定的调度算法，实现将其调度至后端的RealServer，由后端RealServer响应请求报文。
实验环境 ==> CentOS 7.x
实验目的 ==> 通过Keepalived配置管理LVS，并对后端RealServer进行健康状态检测
实验主机 ==> 一共四台主机，分别如下。
192.168.10.6（主机名：node1）
192.168.10.8（主机名：node2）
192.168.10.11（主机名：rs1）
192.168.10.12（主机名：rs2）
实验前提 ==> 高可用对之间时间同步（可通过周期性任务来实现）
实验操作如下。
1、编译Keepalived配置文件
2、启动Keepalived服务
(1) 在node2（192.168.10.8）上
[[email protected] ~]# systemctl start keepalived.service [[email protected] ~]# ifconfig ens34: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.10.8 netmask 255.255.255.0 broadcast 192.168.10.255 ether 00:0c:29:ef:52:87 txqueuelen 1000 (Ethernet) RX packets 17975 bytes 6997522 (6.6 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 2636 bytes 275578 (269.1 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 ens34:0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.100.7 netmask 255.255.255.255 broadcast 0.0.0.0 ether 00:0c:29:ef:52:87 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 0 (Local Loopback) 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
由于此时只有node2节点开启keepalived服务，因此VIP配置在node2节点上。现在在node1节点上也开启keepalived服务，由于node1的优先级比node2高，因此VIP会漂移到node1节点上。
(2) 在node1（192.168.10.6）上
[[email protected] ~]# systemctl start keepalived.service [[email protected] ~]# ifconfig ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.10.6 netmask 255.255.255.0 broadcast 192.168.10.255 ether 00:0c:29:f7:b3:4e txqueuelen 1000 (Ethernet) RX packets 13628 bytes 8098564 (7.7 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 11863 bytes 1007226 (983.6 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 ens33:0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.100.7 netmask 255.255.255.255 broadcast 0.0.0.0 ether 00:0c:29:f7:b3:4e 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 0 (Local Loopback) RX packets 9 bytes 600 (600.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 9 bytes 600 (600.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
2、配置RealServer的服务资源
(1) 在rs1（192.168.10.11）上
[[email protected] ~]# yum -y install httpd [[email protected] ~]# echo "<h1>RealServer 1</h1>" > /var/www/html/index.html [[email protected] ~]# systemctl start httpd.service :::* [[email protected] ~]# ss -tnl | grep :80 LISTEN 0 128 :::80 :::*
(2) 在rs2（192.168.10.12）上
[[email protected] ~]# yum -y install httpd [[email protected] ~]# echo "<h1>RealServer 2</h1>" > /var/www/html/index.html [[email protected] ~]# systemctl start httpd.service [[email protected] ~]# ss -tnl | grep :80 LISTEN 0 128 :::80 :::*
3、配置Director为Sorry Server
(1) 在node1（192.168.10.6）上
[[email protected] ~]# yum -y install httpd [[email protected] ~]# echo "<h1>Sorry Server 1</h1>" > /var/www/html/index.html [[email protected] ~]# systemctl start httpd.service [[email protected] ~]# ss -tnl | grep :80 LISTEN 0 128 *:80 *:*
(2) 在node2（192.168.10.8）上
[[email protected] ~]# yum -y install httpd [[email protected] ~]# echo "<h1>Sorry Server 2</h1>" > /var/www/html/index.html [[email protected] ~]# systemctl start httpd.service [[email protected] ~]# ss -tnl | grep :80 LISTEN 0 128 *:80 *:*
4、测试
(1) 在主机（192.168.10.99 ==> FTP服务器）上测试访问VIP（192.168.10.7）的80端口
[[email protected] ~]# curl http://192.168.10.7/index.html <h1>RealServer 1</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>RealServer 2</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>RealServer 1</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>RealServer 2</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>RealServer 1</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>RealServer 2</h1>
结果为根据rr调度算法将请求报文转发至RealServer1和RealServer2.
此时在node1（192.168.10.6）上用ipvsadm命令查看集群服务。
[[email protected] keepalived]# ipvsadm -Ln IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.10.7:80 rr -> 192.168.10.11:80 Route 1 0 3 -> 192.168.10.12:80 Route 1 0 3
(2) 停止RealServer 1上的Web服务，再进行测试
[[email protected] ~]# systemctl stop httpd.service
在192.168.10.99上再次请求，结果如下。
[[email protected] ~]# curl http://192.168.10.7/index.html <h1>RealServer 1</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>RealServer 1</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>RealServer 1</h1> [[email protected] ~]# curl http://192.168.10.7/index.html
此时在node1（192.168.10.6）上用ipvsadm命令查看集群服务。
[[email protected] ~]# ipvsadm -Ln IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.10.7:80 rr -> 192.168.10.11:80 Route 1 0 3
可以发现，Keepalived服务通过IPVS Wrapper这个底层接口分许Keepalived配置文件，并将RealServer 2移除了。
(3) 停止RealServer 2上的Web服务，再进行测试
[[email protected] ~]# systemctl stop httpd.service
在192.168.10.99上再次请求，结果如下。
[[email protected] ~]# curl http://192.168.10.7/index.html <h1>Sorry Server 1</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>Sorry Server 1</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>Sorry Server 1</h1>
此时在node1（192.168.10.6）上用ipvsadm命令查看。
[[email protected] ~]# ipvsadm -Ln IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.10.7:80 rr -> 127.0.0.1:80 Route 1 0 3
可以发现，Keepalived服务已经将RealServer 1移除了，这时已经没有一台RealServer提供Web服务了。而当Keepalived检测到所有RealServer都故障时，会由Sorry Server对客户端请求进行响应。
(4) 让node1节点下线，测试node2节点是否能够接管node1的VIP和服务资源
[[email protected] ~]# systemctl stop keepalived.service
在node2节点上查看IP，如下。
[[email protected] ~]# ifconfig ens34: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.10.8 netmask 255.255.255.0 broadcast 192.168.10.255 ether 00:0c:29:ef:52:87 txqueuelen 1000 (Ethernet) RX packets 23876 bytes 7443422 (7.0 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 5114 bytes 527694 (515.3 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 ens34:0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.10.7 netmask 255.255.255.255 broadcast 0.0.0.0 ether 00:0c:29:ef:52:87 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 0 (Local Loopback) RX packets 19 bytes 1252 (1.2 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 19 bytes 1252 (1.2 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
可以发现，node2已经接管了node1的工作。
此时仍然没有一台RealServer提供服务，调度器的VIP漂移至node2节点上，我们在192.168.10.99主机上再进行测试。
[[email protected] ~]# curl http://192.168.10.7/index.html <h1>Sorry Server 2</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>Sorry Server 2</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>Sorry Server 2</h1>
此时Say sorry的web服务器是node2。
(5) 再次启动rs1和rs2，并进行测试
启动完rs1和rs2上的Web服务后，在node2（192.168.10.8）节点上使用ipvsadm命令查看集群服务。
[[email protected] ~]# ipvsadm -Ln IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.10.7:80 rr -> 192.168.10.11:80 Route 1 0 0 -> 192.168.10.12:80 Route 1 0 0
可以发现，一旦rs1和rs2故障修复完成，能够正常提供服务时，会立即被Keepalived服务检测到，并将其添加到调度器的正常转发队列中。此时前端调度器由node2接管资源。在192.168.10.99主机上再进行测试。
[[email protected] ~]# curl http://192.168.10.7/index.html <h1>RealServer 1</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>RealServer 2</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>RealServer 1</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>RealServer 2</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>RealServer 1</h1> [[email protected] ~]# curl http://192.168.10.7/index.html <h1>RealServer 2</h1>
实验完成！
转载于:https://blog.51cto.com/xuweitao/1954355