LVS-DR负载均衡及keepalived高可用的部署
LVS-DR负载均衡
server1:作为LinuxDirector
1.安装ipvsadm（rh6.5需要配置yum源）
[root@server1 ~]# cat /etc/yum.repos.d/rhel-source.repo
[rhel-source]
name=Red Hat Enterprise Linux $releasever - $basearch - Source
baseurl=http://172.25.254.79/rhel6.5
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release
[HighAvailability]
name=HighAvailability
baseurl=http://172.25.254.79/rhel6.5/HighAvailability
enabled=1
gpgcheck=0
[LoadBalancer]
name=LoadBalancer
baseurl=http://172.25.254.79/rhel6.5/LoadBalancer
enabled=1
gpgcheck=0
[ResilientStorage]
name=ResilientStorage
baseurl=http://172.25.254.79/rhel6.5/ResilientStorage
enabled=1
gpgcheck=0
[ScalableFileSystem]
name=ScalableFileSystem
baseurl=http://172.25.254.79/rhel6.5/ScalableFileSystem
enabled=1
gpgcheck=0添加ipvsadm策略，将real-server与LinuxDIrector通过VIP绑定
[root@server1 ~]# ipvsadm -A -t 172.25.254.100:80 -s rr ##添加VIP策略
[root@server1 ~]# ipvsadm -a -t 172.25.254.100:80 -r 172.25.254.241:80 -g ##与172.25.254.241绑定
[root@server1 ~]# ipvsadm -a -t 172.25.254.100:80 -r 172.25.254.1:80 -g[root@server1 ~]# ipvsadm -l ##list ipvsadm table
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 172.25.254.100:http rr
-> server3:http Route 1 0 0
-> server2:http Route 1 0 0 [root@server1 ~]# /etc/init.d/ipvsadm save #保存策略
[root@server1 ~]# ip addr add 172.25.254.100/24 dev eth0 #给网卡添加real_server ip
[root@server1 ~]# ip addr | grep 100/24
inet 172.25.254.100/24 scope global secondary eth0server2:(real-server)
[root@server2 ~]# /etc/init.d/arptables_jf start ##使客户机不能直接通过100端口访问
[root@server2 ~]# service httpd start
Redirecting to /bin/systemctl start httpd.service
[root@server2 ~]# echo "server2" > /var/www/html/index.html
[root@server2 ~]# curl localhost
server2
[root@server2 ~]# ip addr add 172.25.254.100/24 dev eth0 ##通过VIP对Director识别server3:(real-server)
[root@server3 ~]# /etc/init.d/arptables_jf start
[root@server3 ~]# echo "server3" > /var/www/html/index.html
[root@server3 ~]# curl localhost
server3
[root@server3 ~]# ip addr add 172.25.254.100/24 dev eth0foundation(客户机):
lvs调度器将数据帧中的mac地址动态地更改server2或server3的mac地址，将修改后的数据帧发送到局域网上，server2/3发现目标的VIP是我这个设备上的，就根据路由表，直接相应客户端。
##轮询测试
[root@79 ~]# curl 172.25.254.100
server2
[root@79 ~]# curl 172.25.254.100
server3
[root@79 ~]# curl 172.25.254.100
server2
[root@79 ~]# curl 172.25.254.100
server3[root@79 lvs]# arp -d 172.25.254.100 ##清理100的arp缓存
[root@79 lvs]# arp -e 172.25.254.100 ##查看ip源mac地址
Address HWtype HWaddress Flags Mask Iface
172.25.254.100 ether 52:54:00:95:05:b1 C br0
[root@79 lvs]# ip addr ##mac地址与server1相同
18: vnet2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br0 state UNKNOWN qlen 500
link/ether fe:54:00:95:05:b1 brd ff:ff:ff:ff:ff:ff二、Ldirectord 实现lvs健康检查
ldirectord用来实现LVS负载均衡资源在主、备节点间的故障转移。在首次启动时，ldirectord可以自动创建IPVS表。此外，它还可以监控各RealServer的运行状态，一旦发现某RealServer运行异常时，还可以将其从IPVS表中移除。
ldirectord 进程通过向RealServer的RIP发送资源访问请求并通过由RealServer返回的响应信息来确定RealServer的运行状态。在 Director上，每一个VIP需要一个单独的ldirectord进程。如果RealServer不能正常响应Director上 ldirectord的请求，ldirectord进程将通过ipvsadm命令将此RealServer从IPVS表中移除。而一旦 RealServer再次上线，ldirectord会将其重新添加至IPVS表中
[root@server1 ~]# yum install -y ldirectord-3.9.5-3.1.x86_64.rpm
[root@server1 ~]# cd /etc/ha.d/
[root@server1 ha.d]# ls
resource.d shellfuncs
[root@server1 ha.d]# cp /usr/share/doc/ldirectord-3.9.5/ldirectord.cf /etc/ha.d/[root@server1 ha.d]# vim ldirectord.cf
virtual=172.25.27.100:80 # 此项用来定义LVS服务及其使用的VIP和PORT
real=172.25.254.1:80 gate # 定义RealServer，语法：real=RIP:port gate|masq|ipip [weight]
real=172.25.254.241:80 gate
fallback=127.0.0.1:80 gate # 定义RealServer，语法：real=RIP:port gate|masq|ipip [weight]
service=http # 定义基于什么服务来测试RealServer；
scheduler=rr # 调度算法为rr
#persistent=600 # 持久连接超时时间；
#netmask=255.255.255.255
protocol=tcp # 定义此虚拟服务用到的协议；
checktype=negotiate # ldirectord进程用于监控RealServer的方法；{negotiate|connect|A number|off}
checkport=80 # 指健康检查使用的端口；
request="index.html" # 检查RealServer用到的页面
receive="Test Page" # 检查RealServer用到的页面内容
virtualhost=www.x.y.z
[root@server1 ha.d]# /etc/init.d/ldirectord start
当把server2的apache关掉后
[root@server1 ~]# ipvsadm -L
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 172.25.254.100:http rr
-> server3:http Route 1 0 0 foundation:
[root@79 ~]# curl 172.25.254.100
server3
[root@79 ~]# curl 172.25.254.100
server3提供当后端RS全部宕掉后，返回的fallback页面，为本机httpd服务:
三、keepalived高可用
Keepalived是基于vrrp协议的一款高可用软件。Keepalived有一台主服务器和多台备份服务器，在主服务器和备份服务器上面部署相同的服务配置，使用一个虚拟IP地址对外提供服务，当主服务器出现故障时，虚拟IP地址会自动漂移到备份服务器。
1.源码安装Keepalived
[root@server1 ~]# /etc/init.d/ldirectord stop #由于ldirectord 与Keepalived冲突，必须将ldirectord停掉
[root@server1 ~]# /etc/init.d/ldirectord stop
Stopping ldirectord... Success
##由于ldirectord 开机自启，所以必须将其开机自启关掉
[root@server1 ~]# chkconfig ldirectord off
[root@server1 ~]# tar zxf keepalived-1.3.6.tar.gz
[root@server1 ~]# cd keepalived-1.3.6
[root@server1 ~]# ./configure --prefix=/usr/local/keepalived --with-init=SYSV
[root@server1 ~]# make
[root@server1 ~]# make install2.Keepalived配置
root@server1 etc]# cd /usr/local/keepalived/etc/rc.d/init.d/
[root@server1 init.d]# ls
Keepalived
##由于keepalived所识别的环境与当前系统不符，所以需要制作软链接
[root@server1 init.d]# ln -s /usr/local/keepalived/etc/keepalived/ /etc/
[root@server1 init.d]# ln -s /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
[root@server1 init.d]# ln -s /usr/local/keepalived/sbin/keepalived /sbin/
[root@server1 init.d]# ln -s /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/[root@server1 keepalived]# cd /usr/local/keepalived/etc/rc.d/init.d/
[root@server1 init.d]# chmod +x keepalived #加可执行权限
[root@server1 keepalived]# cd /etc/keepalived[root@server1 keepalived]# vim /etc/keepalived/keepalived.conf
global_defs {
notification_email {
acassen@firewall.loc
failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.lo
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
vrrp_skip_check_adv_addr
#vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.25.254.100
}
}
virtual_server 172.25.27.100 80 { ##虚拟主机
delay_loop 6
lb_algo rr
lb_kind DR ##是使用的DR模型
# persistence_timeout 50 ##先将此注释掉，可以更加直观的感受到两台rs使用的DR进行的轮转
protocol TCP
real_server 172.25.27.2 80 {
##real_server主机地址和端口两台rs均是使用的80端口
weight 1 ##权重是可以自己进行修改的，在实际使用中，权重使用的不一样是因为，权重较重一方的服务器性能更加好
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
real_server 172.25.254.141 80 {
weight 1
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}foundation:
[root@79 ~]# curl 172.25.254.100
server2
[root@79 ~]# curl 172.25.254.100
server3
[root@79 ~]# curl 172.25.254.100
server2
[root@79 ~]# curl 172.25.254.100
server33.keepalived的bacup配置
打开server4作为从服务器，当主服务器故障时，从服务器会替代它的工作，并把故障的服务器剔除。
将server4按照前面步骤布置keeplived ，可直接将server1的keeplived 配置文件复制过来，进行稍作修改
[root@server4 keepalived]# vim keepalived.conf #修改state 和 priority
vrrp_instance VI_1 {
state BACKUP #将状态由原来的master 改为备用
interface eth0
virtual_router_id 51
priority 50 #更改优先级
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
[root@server4 keepalived]# /etc/init.d/keepalived start
[root@server4 ~]# ip addr add 172.25.254.100/24 dev eth0 #添加real_server ip
server1:
[root@server1～]#echo c > /proc/sysrq-trigger #故意让系统崩溃，实现宕机的目的foundation:
检测仍能正常工作
[root@79 ~]# curl 172.25.254.100
server2
[root@79 ~]# curl 172.25.254.100
server3
[root@79 ~]# curl 172.25.254.100
server2
[root@79 ~]# curl 172.25.254.100
server3
测试并查看IP 和mac 地址，发现此时服务已经完全有server4接管，从而实现了lvs集群高可用原理：
LVS三种负载均衡方式（VS/NAT、VS/TUN、VS/DR）