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keepalived
keepalived+lvs实现高可用的负载均衡
测试
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keepalived
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keepalived一款轻量级高可用软件，工作于layer3, 4 & 5，不同于前几篇博文中的Heartbeat、Corosync等软件的实现机制不同，它采用虚拟路由冗余协议（Virual Router Redundancy Protocal）来实现并且完美的与lvs结合，由于底层使用虚拟路由冗余协议，因此Keepalived具有切换速度快的特点，工作在layer3的keepalived定期向服务器群组中发送ICMP数据包宣告自己存活与否，工作在layer3的keepalived支持以检测TCP端口状态的方式来判定后台Realserver故障与否，自动并将那些判定为故障的后台Realserver从ipvs规则中踢出，工作在layer5可以支持用户自动以脚本来实现相应的智能操作。此lvs也可以结合ldirectord来实现对后台realserver的动态监测，相对于keepalived来说ldirectord属于重量级别的，部署和使用的灵活程度没有前者方便，本文将介绍keepalived。
keepalived+lvs实现高可用的负载均衡
架构图：
realserver端脚本
#!/bin/bash#
# Script to start LVS DR real server.
# description: LVS DR real server
#
. /etc/rc.d/init.d/functions
VIP=192.168.1.33
host=`/bin/hostname`
case "$1" in
start)
# Start LVS-DR real server on this machine.
/sbin/ifconfig lo down
/sbin/ifconfig lo up
echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore
echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce
echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
/sbin/ifconfig lo:0 $VIP broadcast $VIP netmask 255.255.255.255 up
/sbin/route add -host $VIP dev lo:0
;;
stop)
# Stop LVS-DR real server loopback device(s).
/sbin/ifconfig lo:0 down
echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore
echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce
echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore
echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce
;;
status)
# Status of LVS-DR real server.
islothere=`/sbin/ifconfig lo:0 | grep $VIP`
isrothere=`netstat -rn | grep "lo:0" | grep $VIP`
if [ ! "$islothere" -o ! "isrothere" ];then
# Either the route or the lo:0 device
# not found.
echo "LVS-DR real server Stopped."
else
echo "LVS-DR real server Running."
fi
;;
*)
# Invalid entry.
echo "$0: Usage: $0 {start|status|stop}"
exit 1
;;
esac
安装httpd并建立测试页面如下：
安装ipvsadm和keepalived
yum install ipvsadmrpm -ivh keepalived-1.2.7-5.el5.i386.rpm
director_master的配置vim /etc/keepalived/keepalived.conf
! Configuration File for keepalivedglobal_defs { notification_email { root@localhost #报警收件人地址 } notification_email_from root@localhost #报警发件人地址 smtp_server 127.0.0.1 #设置smtp服务地址 smtp_connect_timeout 30 #设置连接smtp服务的超时时间 router_id LVS_DEVEL #发送邮件的主体信息}vrrp_script chk_schedown { #自定义脚本 script "[ -e /etc/keepalived/down ] && exit 1 || exit 0" interval 1 #重试时间间隔 weight -5 #减权重 fall 2 rise 1}vrrp_instance VI_1 { state MASTER #制定keepalived角色 interface eth0 #制定检测网络接口 virtual_router_id 54 #虚拟路由标示码 priority 100 #权重，1-255之间 advert_int 1 #设置同步检查的时间间隔，单位是秒 authentication { auth_type PASS #验证类型为PASS auth_pass soulboy #验证密码 } virtual_ipaddress { 192.168.1.33/24 dev eth0 label eth0:0 #设置虚拟IP } track_script { chk_schedown } notify_master "/etc/keepalived/notify.sh -n master -a 192.168.1.33" notify_backup "/etc/keepalived/notify.sh -n backup -a 192.168.1.33" notify_fault "/etc/keepalived/notify.sh -n fault -a 192.168.1.33" }virtual_server 192.168.1.33 80 { #定义虚拟服务器 delay_loop 6 #设置健康检查时间 lb_algo wrr #设置负载调度算法 lb_kind DR #设置LVS工作模式 nat_mask 255.255.255.0 persistence_timeout 50 protocol TCP #设置转发协议的类型 sorry_server 127.0.0.1 80 #设置紧急服务器 real_server 192.168.1.10 80 { weight 1 HTTP_GET { url { path / status_code 200 } connect_timeout 2 nb_get_retry 3 delay_before_retry 1 }} real_server 192.168.1.20 80 { weight 1 HTTP_GET { url { path / status_code 200 } connect_timeout 2 nb_get_retry 3 delay_before_retry 1 } } }}
director_backup的配置vim /etc/keepalived/keepalived.conf
! Configuration File for keepalivedglobal_defs { notification_email { root@localhost } notification_email_from root@localhost smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id LVS_DEVEL}vrrp_script chk_schedown { script "[ -e /etc/keepalived/down ] && exit 1 || exit 0" interval 1 weight -5 fall 2 rise 1}vrrp_instance VI_1 { state BACKUP interface eth0 virtual_router_id 54 priority 99 advert_int 1 authentication { auth_type PASS auth_pass soulboy } virtual_ipaddress { 192.168.1.33/24 dev eth0 label eth0:0 } track_script { chk_schedown } notify_master "/etc/keepalived/notify.sh -n master -a 192.168.1.33" notify_backup "/etc/keepalived/notify.sh -n backup -a 192.168.1.33" notify_fault "/etc/keepalived/notify.sh -n fault -a 192.168.1.33"}virtual_server 192.168.1.33 80 { delay_loop 6 lb_algo wrr lb_kind DR nat_mask 255.255.255.0 persistence_timeout 50 protocol TCP sorry_server 127.0.0.1 80 real_server 192.168.1.10 80 { weight 1 HTTP_GET { url { path / status_code 200 } connect_timeout 2 nb_get_retry 3 delay_before_retry 1 }} real_server 192.168.1.20 80 { weight 1 HTTP_GET { url { path / status_code 200 } connect_timeout 2 nb_get_retry 3 delay_before_retry 1 } } }}
通知脚本vim /etc/keepalived/notify.sh
#!/bin/bash#ifalias=${2:-eth0:0}interface=$(echo $ifalias | awk -F: '{print $1}')vip=$(ip addr show $interface | grep $ifalias | awk '{print $2}')contact='root@localhost'workspace=$(dirname $0)notify() { subject="$ip change to $1" body="$ip change to $1 $(date '+%F %H:%M:%S')" echo $body | mail -s "$1 transition" $contact}case "$1" in master) notify master exit 0 ;; backup) notify backup /etc/rc.d/init.d/httpd restart exit 0 ;; fault) notify fault exit 0 ;; *) echo 'Usage: $(basename $0) {master|backup|fault}' exit 1 ;;esac
测试
启动director_master的keepalive服务并查看ipvs规则
#####查看ipvs规则[root@master ~]# ipvsadm -L -nIP Virtual Server version 1.2.1 (size=4096)Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConnTCP 192.168.1.33:80 wrr -> 192.168.1.20:80 Route 1 0 0 -> 192.168.1.10:80 Route 1 0 0#####查看网络信息[root@master ~]# ifconfigeth0 Link encap:Ethernet HWaddr 00:0C:29:C2:5E:01 inet addr:192.168.1.61 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:fec2:5e01/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:67996 errors:0 dropped:0 overruns:0 frame:0 TX packets:116217 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:15418633 (14.7 MiB) TX bytes:8387202 (7.9 MiB) Interrupt:67 Base address:0x2024eth0:0 Link encap:Ethernet HWaddr 00:0C:29:C2:5E:01 inet addr:192.168.1.33 Bcast:0.0.0.0 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 Interrupt:67 Base address:0x2024
启动director_backup的keepalive服务并查看ipvs规则
#####查看ipvs规则[root@backup ~]# ipvsadm -L -nIP Virtual Server version 1.2.1 (size=4096)Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConnTCP 192.168.1.33:80 wrr -> 192.168.1.20:80 Route 1 0 0 -> 192.168.1.10:80 Route 1 0 0#####查看网络信息[root@backup ~]# ifconfigeth0 Link encap:Ethernet HWaddr 00:0C:29:FA:52:D6 inet addr:192.168.1.62 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:fefa:52d6/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:115068 errors:0 dropped:0 overruns:0 frame:0 TX packets:82940 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:19740061 (18.8 MiB) TX bytes:6476242 (6.1 MiB) Interrupt:67 Base address:0x2024
使用客户端访问VIP
[root@master ~]# service keepalived stopStopping keepalived: [ OK ][root@master ~]# ifconfigeth0 Link encap:Ethernet HWaddr 00:0C:29:C2:5E:01 inet addr:192.168.1.61 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:fec2:5e01/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:69371 errors:0 dropped:0 overruns:0 frame:0 TX packets:118587 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:15609985 (14.8 MiB) TX bytes:8588490 (8.1 MiB) Interrupt:67 Base address:0x2024
在director_backup查看网络信息，发现VIP已成功转移
[root@backup ~]# ifconfigeth0 Link encap:Ethernet HWaddr 00:0C:29:FA:52:D6 inet addr:192.168.1.62 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:fefa:52d6/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:116816 errors:0 dropped:0 overruns:0 frame:0 TX packets:84293 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:19932196 (19.0 MiB) TX bytes:6597535 (6.2 MiB) Interrupt:67 Base address:0x2024eth0:0 Link encap:Ethernet HWaddr 00:0C:29:FA:52:D6 inet addr:192.168.1.33 Bcast:0.0.0.0 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 Interrupt:67 Base address:0x2024
停止realserver_one的httpd服务
[root@realserver_one ~]# service httpd stopStopping httpd: [ OK ]
director_backup查看ipvs规则，发现realserver_one已经被踢出
[root@backup ~]# ipvsadm -L -nIP Virtual Server version 1.2.1 (size=4096)Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConnTCP 192.168.1.33:80 wrr -> 192.168.1.20:80 Route 1 0 0
客户端访问VIP发现页面恒为node2
[root@realserver_two ~]# service httpd stopStopping httpd: [ OK ]
director_backup查看ipvs规则，发现紧急站点生效
[root@backup ~]# ipvsadm -L -nIP Virtual Server version 1.2.1 (size=4096)Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConnTCP 192.168.1.33:80 wrr -> 127.0.0.1:80 Local 1 0 0
客户端访问VIP发现页面为自定义警告页面
分别启动realserver_one和realserver_two的httpd服务
#####realserver_one[root@realserver_one ~]# service httpd startStarting httpd: httpd: apr_sockaddr_info_get() failed for realserver_onehttpd: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName [ OK ]#####realserver_two[root@realserver_two ~]# service httpd startStarting httpd: httpd: apr_sockaddr_info_get() failed for realserver_twohttpd: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName [ OK ]
再次查看director_backup发现ipvs规则已经恢复
[root@backup ~]# ipvsadm -L -nIP Virtual Server version 1.2.1 (size=4096)Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConnTCP 192.168.1.33:80 wrr -> 192.168.1.20:80 Route 1 0 0 -> 192.168.1.10:80 Route 1 0 0
客户端访问VIP发现负载正常
启动director_master的keepalived服务并查看网络信息发现VIP成功转移
[root@master ~]# service keepalived startStarting keepalived: [ OK ][root@master ~]# ifconfigeth0 Link encap:Ethernet HWaddr 00:0C:29:C2:5E:01 inet addr:192.168.1.61 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:fec2:5e01/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:70394 errors:0 dropped:0 overruns:0 frame:0 TX packets:118644 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:15679204 (14.9 MiB) TX bytes:8593207 (8.1 MiB) Interrupt:67 Base address:0x2024eth0:0 Link encap:Ethernet HWaddr 00:0C:29:C2:5E:01 inet addr:192.168.1.33 Bcast:0.0.0.0 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 Interrupt:67 Base address:0x2024
在director_backup查看网络信息发现VIP消失
[root@backup ~]# ifconfigeth0 Link encap:Ethernet HWaddr 00:0C:29:FA:52:D6 inet addr:192.168.1.62 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:fefa:52d6/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:118485 errors:0 dropped:0 overruns:0 frame:0 TX packets:87004 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:20112822 (19.1 MiB) TX bytes:6791097 (6.4 MiB) Interrupt:67 Base address:0x2024lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:6781 errors:0 dropped:0 overruns:0 frame:0 TX packets:6781 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:2122280 (2.0 MiB) TX bytes:2122280 (2.0 MiB)
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