LVS+Keepalived構建高可用負載均衡(測試篇)
2024-09-01 13:44:48
供稿：網友
一、 啟動LVS高可用集群服務
首先，啟動每個real server節點的服務：
[root@localhost ~]# /etc/init.d/lvsrs start
start LVS of REALServer
然后，分別在主備Director Server啟動Keepalived服務：
[root@DR1 ~]#/etc/init.d/Keepalived start
[root@DR1 ~]#/ ipvsadm -L
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP bogon:http rr
-> real-server1:http Route 1 1 0
-> real-server2:http Route 1 1 0
此時查看Keepalived服務的系統日志信息如下:
[root@localhost ~]# tail -f /var/log/messages
Feb 28 10:01:56 localhost Keepalived: Starting Keepalived v1.1.19 (02/27,2011)
Feb 28 10:01:56 localhost Keepalived_healthcheckers: Netlink reflector reports IP 192.168.12.25 added
Feb 28 10:01:56 localhost Keepalived_healthcheckers: Opening file '/etc/keepalived/keepalived.conf'.
Feb 28 10:01:56 localhost Keepalived_healthcheckers: Configuration is using : 12063 Bytes
Feb 28 10:01:56 localhost Keepalived: Starting Healthcheck child process, pid=4623
Feb 28 10:01:56 localhost Keepalived_vrrp: Netlink reflector reports IP 192.168.12.25 added
Feb 28 10:01:56 localhost Keepalived: Starting VRRP child process, pid=4624
Feb 28 10:01:56 localhost Keepalived_healthcheckers: Activating healtchecker for service [192.168.12.246:80]
Feb 28 10:01:56 localhost Keepalived_vrrp: Opening file '/etc/keepalived/keepalived.conf'.
Feb 28 10:01:56 localhost Keepalived_healthcheckers: Activating healtchecker for service [192.168.12.237:80]
Feb 28 10:01:57 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATE
Feb 28 10:01:58 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATE
Feb 28 10:01:58 localhost Keepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.
Feb 28 10:01:58 localhost Keepalived_healthcheckers: Netlink reflector reports IP 192.168.12.135 added
Feb 28 10:01:58 localhost avahi-daemon[2778]: Registering new address record for 192.168.12.135 on eth0.
二、 高可用性功能測試
高可用性是通過LVS的兩個Director Server完成的，為了模擬故障，我們先將主Director Server上面的Keepalived服務停止，然后觀察備用Director Server上Keepalived的運行日志，信息如下：
Feb 28 10:08:52 lvs-backup Keepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATE
Feb 28 10:08:54 lvs-backup Keepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATE
Feb 28 10:08:54 lvs-backup Keepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.
Feb 28 10:08:54 lvs-backup Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 192.168.12.135
Feb 28 10:08:54 lvs-backup Keepalived_vrrp: Netlink reflector reports IP 192.168.12.135 added
Feb 28 10:08:54 lvs-backup Keepalived_healthcheckers: Netlink reflector reports IP 192.168.12.135 added
Feb 28 10:08:54 lvs-backup avahi-daemon[3349]: Registering new address record for 192.168.12.135 on eth0.
Feb 28 10:08:59 lvs-backup Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 192.168.12.135
從日志中可以看出，主機出現故障后，備機立刻檢測到，此時備機變為MASTER角色，并且接管了主機的虛擬IP資源，最后將虛擬IP綁定在eth0設備上。
接著，重新啟動主Director Server上的Keepalived服務，繼續觀察備用Director Server的日志狀態：
備用Director Server的日志狀態：
Feb 28 10:12:11 lvs-backup Keepalived_vrrp: VRRP_Instance(VI_1) Received higher prio advert
Feb 28 10:12:11 lvs-backup Keepalived_vrrp: VRRP_Instance(VI_1) Entering BACKUP STATE
Feb 28 10:12:11 lvs-backup Keepalived_vrrp: VRRP_Instance(VI_1) removing protocol VIPs.
Feb 28 10:12:11 lvs-backup Keepalived_vrrp: Netlink reflector reports IP 192.168.12.135 removed
Feb 28 10:12:11 lvs-backup Keepalived_healthcheckers: Netlink reflector reports IP 192.168.12.135 removed
Feb 28 10:12:11 lvs-backup avahi-daemon[3349]: Withdrawing address record for 192.168.12.135 on eth0.
從日志可知，備機在檢測到主機重新恢復正常后，重新返回BACKUP角色，并且釋放了虛擬IP資源。
三、 負載均衡測試
這里假定兩個real server節點配置www服務的網頁文件根目錄均為/webdata/www目錄，然后分別執行如下操作：
在real server1 執行：
echo "This is real server1" /webdata/www/index.html
在real server2 執行：
echo "This is real server2" /webdata/www/index.html
接著打開瀏覽器，訪問這個地址，然后不斷刷新此頁面，如果能分別看到“This is real server1”和“This is real server2”就表明LVS已經在進行負載均衡了。
四、 故障切換測試
故障切換是測試當某個節點出現故障后，Keepalived監控模塊是否能及時發現，然后屏蔽故障節點，同時將服務轉移到正常節點來執行。
這里我們將real server 1節點服務停掉，假定這個節點出現故障，然后查看主、備機日志信息，相關日志如下：
Feb 28 10:14:12 localhost Keepalived_healthcheckers: TCP connection to [192.168.12.246:80] failed !!!
Feb 28 10:14:12 localhost Keepalived_healthcheckers: Removing service [192.168.12.246:80] from VS [192.168.12.135:80]
Feb 28 10:14:12 localhost Keepalived_healthcheckers: Remote SMTP server [192.168.12.1:25] connected.
Feb 28 10:14:12 localhost Keepalived_healthcheckers: SMTP alert successfully sent.
通過日志可以看出，Keepalived監控模塊檢測到192.168.12.246這臺主機出現故障后，將此節點從集群系統中剔除掉了。
此時訪問這個地址，應該只能看到“This is real server2”了，這是因為節點1出現故障，而Keepalived監控模塊將節點1從集群系統中剔除了。
下面重新啟動real server 1節點的服務，可以看到Keepalived日志信息如下：
Feb 28 10:15:48 localhost Keepalived_healthcheckers: TCP connection to [192.168.12.246:80] success.
Feb 28 10:15:48 localhost Keepalived_healthcheckers: Adding service [192.168.12.246:80] to VS [192.168.12.135:80]
Feb 28 10:15:48 localhost Keepalived_healthcheckers: Remote SMTP server [192.168.12.1:25] connected.
Feb 28 10:15:48 localhost Keepalived_healthcheckers: SMTP alert successfully sent.
從日志可知，Keepalived監控模塊檢測到192.168.12.246這臺主機恢復正常后，又將此節點加入了集群系統中。
此時再次訪問這個地址，然后不斷刷新此頁面，應該又能分別看到“This is real server1”和“This is real server2”頁面了，這說明在real server 1節點恢復正常后，Keepalived監控模塊將此節點加入了集群系統中。
本文出自 “技術成就夢想” 博客
