LVS/NAT + keepalived負載均衡實現
keepalived是分布式部署解決系統高可用的軟件,結合lvs(LinuxVirtual Server)使用,解決單機宕機的問題。
keepalived是一個基於VRRP協議來實現IPVS的高可用的解決方案。對於LVS負載均衡來說,如果前端的調度器direct發生故障,則後端的realserver是無法接受請求並響應的。因此,保證前端direct的高可用性是非常關鍵的,否則後端的服務器是無法進行服務的。而我們的keepalived就可以用來解決單點故障(如LVS的前端direct故障)問題。keepalived的主要工作原理是:運行keepalived的兩臺服務器,其中一臺為
二、測試環境
下面拿4臺虛擬機進行環境測試,實驗環境為centos6.6 x86_64,在lvs NAT模式環境下只有前端兩臺keepalived調度機有公網ip,後端真實機只有內網ip,具體用途和ip如下
服務器類型 | 公網ip | 內網ip |
LVS VIP | 192.168.214.70 | 192.168.211.254 |
Keepalived Master | 192.168.214.76 | 192.168.211.76 |
Keepalived Backup | 192.168.214.77 | 192.168.211.77 |
Realserver A | 192.168.211.79 | |
Realserver B | 192.168.211.83 |
三、軟件安裝
1、安裝lvs所需包ipvsadm
yum install -y ipvsadm
ln -s /usr/src/kernels/`uname -r` /usr/src/linux
lsmod |grep ip_vs
#註意Centos 6.X安裝lvs,使用1.26版本。並且需要先安裝yuminstall libnl* popt* -y
執行ipvsadm(modprobe ip_vs)把ip_vs模塊加載到內核
[root@test85 ~]# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
#IP Virtual Server version 1.2.1 ---- ip_vs內核模塊版本
2、安裝keepalived
yum install -y keepalived
chkconfig keepalived on
註:在centos7系列系統中開機自動啟動使用systemctl enable keepalived
四、開啟路由轉發
在lvs/NAT模式下前端兩臺調度機192.168.211.76和192.168.211.77上需要開啟路由轉發功能
vi /etc/sysctl.conf
修改net.ipv4.ip_forward = 0為net.ipv4.ip_forward= 1
保存退出後,使用systcl –p命令讓其生效
五、keepalived配置
先看下211.76 keepalivedmaster主機上的配置
具體詳細的參數說明見上篇LVS/DR + keepalived負載均衡實現
[root@localhost ~]# cat /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs { notification_email { [email protected] } notification_email_from [email protected] #smtp_server 127.0.0.1 #smtp_connect_timeout 30 router_id LVS_1 #lvs_id LVS_EXAMPLE_01 } vrrp_sync_group VG1 { group { VI_1 VI_GATEWAY } } vrrp_instance VI_1 { state MASTER interface eth0 #公網ip網口 virtual_router_id 51 priority 150 advert_int 1 lvs_sync_daemon_inteface eth0 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.214.70 #公網vip地址 } } vrrp_instance VI_GATEWAY { state MASTER interface eth1 #內網ip網口 lvs_sync_daemon_inteface eth1 virtual_router_id 52 priority 150 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.211.254 #內網vip地址 } } virtual_server 192.168.214.70 80 { delay_loop 6 lb_algo rr lb_kind NAT #使用lvs的NAT工作模式 #nat_mask 255.255.255.0 persistence_timeout 10 protocol TCP real_server 192.168.211.79 80 { TCP_CHECK { connect_timeout 3 connect_port 80 nb_get_retry 3 delay_before_retry 3 } } real_server 192.168.211.83 80 { TCP_CHECK { connect_timeout 3 connect_port 80 nb_get_retry 3 delay_before_retry 3 } } }
再看下211.77 keepalived BACKUP主機上的配置
[root@localhost ~]# cat /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs { notification_email { [email protected] } notification_email_from [email protected] #smtp_server 127.0.0.1 #smtp_connect_timeout 30 router_id LVS_1 #lvs_id LVS_EXAMPLE_02 } vrrp_sync_group VG1 { group { VI_1 VI_GATEWAY } } vrrp_instance VI_1 { state BACKUP interface eth0 lvs_sync_daemon_inteface eth0 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.214.70 } } vrrp_instance VI_GATEWAY { state BACKUP interface eth1 lvs_sync_daemon_inteface eth1 virtual_router_id 52 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.211.254 } } virtual_server 192.168.214.70 80 { delay_loop 6 lb_algo rr lb_kind NAT #nat_mask 255.255.255.0 persistence_timeout 10 protocol TCP real_server 192.168.211.79 80 { TCP_CHECK { connect_timeout 3 connect_port 80 nb_get_retry 3 delay_before_retry 3 } } real_server 192.168.211.83 80 { TCP_CHECK { connect_timeout 3 connect_port 80 nb_get_retry 3 delay_before_retry 3 } } }
六、後端真實機配置
後端兩臺web服務真實機192.168.211.79和192.168.211.83需要配置默認網關為vip內網ip地址192.168.211.254。
註意,線上環境如果更改默認網關為vip內網地址後,可能會造成連接不上服務器,需要提前添加相關靜態路由。
七、啟動keepalived服務及查看相關信息
在211.76和211.77上分別啟動keepalived服務
在211.76keepalived Master主機上查看信息
通過ip addr可以看到vip 地址已經綁定在eth0和eth1網口
[root@localhost ~]# ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu65536 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: eth0:<BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen1000 link/ether 52:54:00:55:b2:d4 brd ff:ff:ff:ff:ff:ff inet 192.168.214.76/24 brd 192.168.214.255 scope global eth0 inet 192.168.214.70/32 scope global eth0 inet6 fe80::5054:ff:fe55:b2d4/64 scope link valid_lft forever preferred_lft forever 3: eth1:<BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen1000 link/ether 52:54:00:85:11:95 brd ff:ff:ff:ff:ff:ff inet 192.168.211.76/24 brd 192.168.211.255 scope global eth1 inet 192.168.211.254/32 scope global eth1 inet6 fe80::5054:ff:fe85:1195/64 scope link valid_lft forever preferred_lft forever 在211.76上查看日誌信息,看到已成功進入keepalived主機模式 [root@localhost ~]# tail -f/var/log/messages May 10 10:25:47 localhostKeepalived_vrrp[6210]: VRRP_Instance(VI_GATEWAY) setting protocol VIPs. May 10 10:25:47 localhost Keepalived_healthcheckers[6209]:Netlink reflector reports IP 192.168.211.254 added May 10 10:25:47 localhostKeepalived_vrrp[6210]: VRRP_Instance(VI_GATEWAY) Sending gratuitous ARPs oneth1 for 192.168.211.254 May 10 10:25:47 localhostKeepalived_vrrp[6210]: VRRP_Group(VG1) Syncing instances to MASTER state May 10 10:25:47 localhostKeepalived_vrrp[6210]: VRRP_Instance(VI_1) EnteringMASTER STATE May 10 10:25:47 localhostKeepalived_vrrp[6210]: VRRP_Instance(VI_1) setting protocol VIPs. May 10 10:25:47 localhost Keepalived_healthcheckers[6209]:Netlink reflector reports IP 192.168.214.70 added May 10 10:25:47 localhostKeepalived_vrrp[6210]: VRRP_Instance(VI_1) Sendinggratuitous ARPs on eth0 for 192.168.214.70 May 10 10:25:52 localhostKeepalived_vrrp[6210]: VRRP_Instance(VI_GATEWAY) Sendinggratuitous ARPs on eth1 for 192.168.211.254 May 10 10:25:52 localhostKeepalived_vrrp[6210]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for192.168.214.70
在211.77上查看日誌信息,看到已成功進入keepalived備機模式
[root@localhost ~]# tail -f/var/log/messages May 10 10:27:54 localhostKeepalived_vrrp[6249]: Opening file '/etc/keepalived/keepalived.conf'. May 10 10:27:54 localhostKeepalived_vrrp[6249]: Configuration is using : 69554 Bytes May 10 10:27:54 localhostKeepalived_vrrp[6249]: Using LinkWatch kernel netlink reflector... May 10 10:27:54 localhostKeepalived_vrrp[6249]: VRRP_Instance(VI_1) Entering BACKUP STATE May 10 10:27:54 localhostKeepalived_vrrp[6249]: VRRP_Instance(VI_GATEWAY) Entering BACKUP STATE May 10 10:27:54 localhost Keepalived_vrrp[6249]:VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)] May 10 10:27:54 localhostKeepalived_vrrp[6249]: VRRP sockpool: [ifindex(3), proto(112), unicast(0),fd(12,13)] May 10 10:27:54 localhostKeepalived_healthcheckers[6248]: Using LinkWatch kernel netlink reflector... May 10 10:27:54 localhostKeepalived_healthcheckers[6248]: Activating healthchecker for service[192.168.211.79]:80 May 10 10:27:54 localhostKeepalived_healthcheckers[6248]: Activating healthchecker for service[192.168.211.83]:80
通過ipvsadm -L –n 查看相應lvs連接信息
[root@localhost ~]# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.214.70:80 rr persistent 10
-> 192.168.211.79:80 Masq 1 0 0
-> 192.168.211.83:80 Masq 1 3 0
八、keepalived測試
使用vip地址192.168.214.70訪問後端192.168.211.79和192.168.211.83的頁面
正常訪問沒問題後,我們來模擬lvs集群故障,讓主備進行自動切換下
首先把keepalived master主機211.76宕機,看備機能否接管過來,vip地址是否會漂移過來
在211.77上查看日誌,發現備機成功切換成了主機狀態,vip地址成功漂移了過來
[root@localhost ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu65536 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: eth0:<BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen1000
link/ether 52:54:00:1b:a2:11 brd ff:ff:ff:ff:ff:ff
inet 192.168.214.77/24 brd 192.168.214.255 scope global eth0
inet 192.168.214.70/32 scope global eth0
inet6 fe80::5054:ff:fe1b:a211/64 scope link
valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP>mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 52:54:00:64:47:7d brd ff:ff:ff:ff:ff:ff
inet 192.168.211.77/24 brd 192.168.211.255 scope global eth1
inet 192.168.211.254/32 scope global eth1
inet6 fe80::5054:ff:fe64:477d/64 scope link
valid_lft forever preferred_lft forever
[root@localhost ~]# tail -f /var/log/messages May 10 10:27:54 localhost Keepalived_vrrp[6249]: Opening file '/etc/keepalived/keepalived.conf'. May 10 10:27:54 localhost Keepalived_vrrp[6249]: Configuration is using : 69554 Bytes May 10 10:27:54 localhost Keepalived_vrrp[6249]: Using LinkWatch kernel netlink reflector... May 10 10:27:54 localhost Keepalived_vrrp[6249]: VRRP_Instance(VI_1) Entering BACKUP STATE May 10 10:27:54 localhost Keepalived_vrrp[6249]: VRRP_Instance(VI_GATEWAY) Entering BACKUP STATE May 10 10:27:54 localhost Keepalived_vrrp[6249]: VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)] May 10 10:27:54 localhost Keepalived_vrrp[6249]: VRRP sockpool: [ifindex(3), proto(112), unicast(0), fd(12,13)] May 10 10:27:54 localhost Keepalived_healthcheckers[6248]: Using LinkWatch kernel netlink reflector... May 10 10:27:54 localhost Keepalived_healthcheckers[6248]: Activating healthchecker for service [192.168.211.79]:80 May 10 10:27:54 localhost Keepalived_healthcheckers[6248]: Activating healthchecker for service [192.168.211.83]:80 May 10 11:09:26 localhost Keepalived_vrrp[6249]: VRRP_Instance(VI_1) Transition to MASTER STATE May 10 11:09:26 localhost Keepalived_vrrp[6249]: VRRP_Group(VG1) Syncing instances to MASTER state May 10 11:09:26 localhost Keepalived_vrrp[6249]: VRRP_Instance(VI_GATEWAY) Transition to MASTER STATE May 10 11:09:27 localhost Keepalived_vrrp[6249]: VRRP_Instance(VI_GATEWAY) Entering MASTER STATE May 10 11:09:27 localhost Keepalived_vrrp[6249]: VRRP_Instance(VI_GATEWAY) setting protocol VIPs. May 10 11:09:27 localhost Keepalived_vrrp[6249]: VRRP_Instance(VI_GATEWAY) Sending gratuitous ARPs on eth1 for 192.168.211.254 May 10 11:09:27 localhost Keepalived_healthcheckers[6248]: Netlink reflector reports IP 192.168.211.254 added May 10 11:09:27 localhost Keepalived_vrrp[6249]: VRRP_Instance(VI_1) Entering MASTER STATE May 10 11:09:27 localhost Keepalived_vrrp[6249]: VRRP_Instance(VI_1) setting protocol VIPs. May 10 11:09:27 localhost Keepalived_vrrp[6249]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 192.168.214.70 May 10 11:09:27 localhost Keepalived_healthcheckers[6248]: Netlink reflector reports IP 192.168.214.70 added May 10 11:09:32 localhost Keepalived_vrrp[6249]: VRRP_Instance(VI_GATEWAY) Sending gratuitous ARPs on eth1 for 192.168.211.254 May 10 11:09:32 localhost Keepalived_vrrp[6249]: VRRP_Instance(VI_1) Sending
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LVS/NAT + keepalived負載均衡實現