nginx+keepalievd，实现负载均衡和故障点切换。keepalived双机热备。
接上文 学习日记4：nginx负载均衡（二）2012.01.08
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到此，整体工作还差一个备用nginx proxy，其中涉及到keepalived，做心跳。
黄线以上做完了。
本次主要做的是1加一台从nginx_proxy ，暂且命令为front2（为从）。之前的nginx_proxy命令为front（为主）
1 在主nginx上配置keepalived。
cd /usr/local/src/ wget http: // keepalived.org/software/keepalived-1.2.7.tar.gz tar -xzvf keepalived- 1.2 . 7 . tar .gz cd keepalived - 1.2 . 7 / . /configure --prefix=/usr/local/keepalived这时候会报错的！
configure: error: !!! OpenSSL is not properly installed on your system. !!! !!! Can not include OpenSSL headers files. !!!缺少gcc，安装下面扩展
yum install gcc gcc -c++ autoconf automake继续编译，下面还会报错，类似这样的错误。
make : *** No targets specified and no makefile found. Stop.
configure: error: ! OpenSSL is not properly installed on your system. configure: error: !对此，我们安装以下扩展即可解决。
yum -y install openssl-devel
yum -y install popt-devel在编译
./configure --prefix=/usr/local/keepalived这时候，会出现下面的结果，这个结果就表明是ok的。到此你的keepalived安装是成功的！
Keepalived configuration ------------------------ Keepalived version : 1.2 . 7 Compiler : gcc Compiler flags : -g - O2 Extra Lib : -lpopt -lssl - lcrypto Use IPVS Framework : Yes IPVS sync daemon support : Yes IPVS use libnl : No Use VRRP Framework : Yes Use VRRP VMAC : Yes SNMP support : No Use Debug flags : No继续下面的操作
make make install cp /usr/local/keepalived/sbin/keepalived /usr/sbin/ cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/ cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/ mkdir /etc/ keepalived cd /etc/ keepalived vim keepalived.conf
keepalived.conf配置文件比较重要
front1 ：主nginx的配置文件如下：
! Configuration File for keepalived global_defs { router_id LVS_01 } vrrp_instance VI_1 { state MASTER #master 主nginx interface eth1 virtual_router_id 51 mcast_src_ip 192.168 . 65.133 #本机ip地址也即主nginx地址 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168 . 65.128 #vip 虚拟出来的ip地址 要求在内网中未被使用 } }到此，主nginx配置完成。同样的操作，在从nginx上也配置一遍。
不过从nginx的配置文件如下：
[root@localhost nginx]# vim /etc/keepalived/ keepalived.conf ! Configuration File for keepalived global_defs { router_id LVS_01 } vrrp_instance VI_1 { state BACKUP #slave interface eth2 virtual_router_id 51 mcast_src_ip 192.168 . 65.137 #slave ip priority 80 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168 . 65.128 #vip } }重启两边的keepalived服务：
[root@localhost conf.d]# service keepalived restart Stopping keepalived: [FAILED] Starting keepalived: [ OK ]主nginx上，用
[root@localhost conf.d]# ip a 1 : lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN link /loopback 00 : 00 : 00 : 00 : 00 : 00 brd 00 : 00 : 00 : 00 : 00 : 00 inet 127.0 . 0.1 / 8 scope host lo inet6 :: 1 / 128 scope host valid_lft forever preferred_lft forever 2 : eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link /ether 00 :0c: 29 : 20 :e9: 20 brd ff:ff:ff:ff:ff:ff inet 192.168 . 65.133 / 24 brd 192.168 . 65.255 scope global eth1 inet 192.168 . 65.128 / 32 scope global eth1 inet6 fe80::20c:29ff:fe20:e920 / 64 scope link valid_lft forever preferred_lft forever到此，我们的vip算是真正的绑定上了。
查看keepalived的日志：
root@localhost conf.d]# tail -f /var/log/ messages Jan 9 18 : 53 : 06 localhost Keepalived_healthcheckers[ 3355 ]: Using LinkWatch kernel netlink reflector... Jan 9 18 : 53 : 06 localhost Keepalived_vrrp[ 3356 ]: Configuration is using : 34824 Bytes Jan 9 18 : 53 : 06 localhost Keepalived_vrrp[ 3356 ]: Using LinkWatch kernel netlink reflector... Jan 9 18 : 53 : 06 localhost Keepalived_vrrp[ 3356 ]: VRRP sockpool: [ifindex( 2 ), proto( 112 ), fd( 11 , 12 )] Jan 9 18 : 53 : 06 localhost Keepalived_vrrp[ 3356 ]: VRRP_Instance(VI_1) Transition to MASTER STATE Jan 9 18 : 53 : 07 localhost Keepalived_vrrp[ 3356 ]: VRRP_Instance(VI_1) Entering MASTER STATE Jan 9 18 : 53 : 07 localhost Keepalived_vrrp[ 3356 ]: VRRP_Instance(VI_1) setting protocol VIPs. Jan 9 18 : 53 : 07 localhost avahi-daemon[ 1765 ]: Registering new address record for 192.168 . 65.128 on eth1.IPv4. Jan 9 18 : 53 : 07 localhost Keepalived_healthcheckers[ 3355 ]: Netlink reflector reports IP 192.168 . 65.128 added Jan 9 18 : 53 : 07 localhost Keepalived_vrrp[ 3356 ]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth1 for 192.168 . 65.128 Jan 9 18 : 53 : 12 localhost Keepalived_vrrp[ 3356 ]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth1 for 192.168 . 65.128从nginx上，同样
[root@localhost nginx]# ip a 1 : lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN link /loopback 00 : 00 : 00 : 00 : 00 : 00 brd 00 : 00 : 00 : 00 : 00 : 00 inet 127.0 . 0.1 / 8 scope host lo inet6 :: 1 / 128 scope host valid_lft forever preferred_lft forever 2 : eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link /ether 00 :0c: 29 :a7: 81 :c7 brd ff:ff:ff:ff:ff:ff inet 192.168 . 65.137 / 24 brd 192.168 . 65.255 scope global eth2 inet6 fe80::20c:29ff:fea7:81c7 / 64 scope link valid_lft forever preferred_lft forever同时；
[root@localhost nginx]# tail -f /var/log/ messages Jan 9 19 : 16 : 25 localhost Keepalived_healthcheckers[ 22420 ]: Registering Kernel netlink reflector Jan 9 19 : 16 : 25 localhost Keepalived_healthcheckers[ 22420 ]: Registering Kernel netlink command channel Jan 9 19 : 16 : 25 localhost Keepalived_vrrp[ 22421 ]: Opening file ' /etc/keepalived/keepalived.conf ' . Jan 9 19 : 16 : 25 localhost Keepalived_healthcheckers[ 22420 ]: Opening file ' /etc/keepalived/keepalived.conf ' . Jan 9 19 : 16 : 25 localhost Keepalived_vrrp[ 22421 ]: Configuration is using : 34822 Bytes Jan 9 19 : 16 : 25 localhost Keepalived_healthcheckers[ 22420 ]: Configuration is using : 4821 Bytes Jan 9 19 : 16 : 25 localhost Keepalived_vrrp[ 22421 ]: Using LinkWatch kernel netlink reflector... Jan 9 19 : 16 : 25 localhost Keepalived_vrrp[ 22421 ]: VRRP_Instance(VI_1) Entering BACKUP STATE Jan 9 19 : 16 : 25 localhost Keepalived_vrrp[ 22421 ]: VRRP sockpool: [ifindex( 2 ), proto( 112 ), fd( 11 , 12 )] Jan 9 19 : 16 : 25 localhost Keepalived_healthcheckers[ 22420 ]: Using LinkWatch kernel netlink reflector...貌似从nginx似乎出了什么问题，先不着急。
这时候我们停止掉主nginx的服务，再看看效果怎么样！
killall nginx再观察从nginx的状态变化
[root@localhost nginx]# tail -f /var/log/ messages Jan 9 19 : 16 : 25 localhost Keepalived_healthcheckers[ 22420 ]: Registering Kernel netlink reflector Jan 9 19 : 16 : 25 localhost Keepalived_healthcheckers[ 22420 ]: Registering Kernel netlink command channel Jan 9 19 : 16 : 25 localhost Keepalived_vrrp[ 22421 ]: Opening file ' /etc/keepalived/keepalived.conf ' . Jan 9 19 : 16 : 25 localhost Keepalived_healthcheckers[ 22420 ]: Opening file ' /etc/keepalived/keepalived.conf ' . Jan 9 19 : 16 : 25 localhost Keepalived_vrrp[ 22421 ]: Configuration is using : 34822 Bytes Jan 9 19 : 16 : 25 localhost Keepalived_healthcheckers[ 22420 ]: Configuration is using : 4821 Bytes Jan 9 19 : 16 : 25 localhost Keepalived_vrrp[ 22421 ]: Using LinkWatch kernel netlink reflector... Jan 9 19 : 16 : 25 localhost Keepalived_vrrp[ 22421 ]: VRRP_Instance(VI_1) Entering BACKUP STATE Jan 9 19 : 16 : 25 localhost Keepalived_vrrp[ 22421 ]: VRRP sockpool: [ifindex( 2 ), proto( 112 ), fd( 11 , 12 )] Jan 9 19 : 16 : 25 localhost Keepalived_healthcheckers[ 22420 ]: Using LinkWatch kernel netlink reflector... Jan 9 19 : 17 : 33 localhost Keepalived_vrrp[ 22421 ]: VRRP_Instance(VI_1) Transition to MASTER STATE Jan 9 19 : 17 : 34 localhost Keepalived_vrrp[ 22421 ]: VRRP_Instance(VI_1) Entering MASTER STATE Jan 9 19 : 17 : 34 localhost Keepalived_vrrp[ 22421 ]: VRRP_Instance(VI_1) setting protocol VIPs. Jan 9 19 : 17 : 34 localhost Keepalived_vrrp[ 22421 ]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth2 for 192.168 . 65.128 Jan 9 19 : 17 : 34 localhost avahi-daemon[ 1810 ]: Registering new address record for 192.168 . 65.128 on eth2.IPv4. Jan 9 19 : 17 : 34 localhost Keepalived_healthcheckers[ 22420 ]: Netlink reflector reports IP 192.168 . 65.128 added Jan 9 19 : 17 : 39 localhost Keepalived_vrrp[ 22421 ]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth2 for 192.168 . 65.128从第33秒后发现，备用nginx已经转为master状态。
再看
[root@localhost nginx]# ip a 1 : lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN link /loopback 00 : 00 : 00 : 00 : 00 : 00 brd 00 : 00 : 00 : 00 : 00 : 00 inet 127.0 . 0.1 / 8 scope host lo inet6 :: 1 / 128 scope host valid_lft forever preferred_lft forever 2 : eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link /ether 00 :0c: 29 :a7: 81 :c7 brd ff:ff:ff:ff:ff:ff inet 192.168 . 65.137 / 24 brd 192.168 . 65.255 scope global eth2 inet 192.168 . 65.128 / 32 scope global eth2 inet6 fe80::20c:29ff:fea7:81c7 / 64 scope link valid_lft forever preferred_lft forever发现没有？vip飘过来了！
针对Keepalived的不足,用check_nginx.sh来监控nginx进程，实现真正意义上的负载均衡高可用.
此脚本思路其实也很简单，即放置在后台一直监控nginx进程；如进程消失，尝试重启nginx，
如是失败则立即停掉本机的keepalived服务，让另一台负载均衡器接手.
vi /shell/nginx_pid. sh ################################################### # !/bin/ bash while : do nginxpid =` ps -C nginx --no-header | wc - l` if [ $nginxpid -eq 0 ] then /usr/local/nginx- 0.8 . 53 /sbin/ nginx sleep 5 if [ $nginxpid -eq 0 ] then /etc/init.d/ keepalived stop fi fi sleep 5 done ###################################################我们仍然可以继续访问我们的站点。至此。故障点切换宣告结束。
分类: linux , nginx , 架构
标签: nginx负载均衡 , nginx+keepalievd , keepalived双机热备
作者： Leo_wl
出处： http://www.cnblogs.com/Leo_wl/
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