Keepalived實作高可用和負載均衡

keepalived是一個類似于layer3, 4 & 7交換機制的軟體，也就是我們平時說的第3層、第4層和第7層交換。Keepalived是自動完成，不需人工幹涉。Keepalived的作用是檢測伺服器的狀态，如果有一台web伺服器當機，或工作出現故障，Keepalived将檢測到，并将有故障的伺服器從系統中剔除，同時使用其他伺服器代替該伺服器的工作，當伺服器工作正常後Keepalived自動将伺服器加入到伺服器群中，這些工作全部自動完成，不需要人工幹涉，需要人工做的隻是修複故障的伺服器。

本篇文章主要講述了用keepalived-1.4.3實作高可用和負載均衡。

作業系統：Linux redhat6.5
高可用結點：server1(master)  server4(backup)
負載均衡節點：server2 server3
源碼包：keepalived-1.4.3.tar.gz

1.keepalived源碼安裝，從網絡上下載下傳源碼包。

[[email protected] ~]# cd keepalived-1.4.3
[[email protected] keepalived-1.4.3]# ./configure --prefix=/usr/local/keepalived --with-init=SYSV
Use IPVS Framework       : Yes
Use VRRP Framework       : Yes
[[email protected] keepalived-1.4.3]# make
[[email protected] keepalived-1.4.3]# make install

[[email protected] ~]# tar zxf keepalived-1.4.3.tar.gz
[[email protected] ~]yum install openssl-devel libnl3-devel ipset-devel iptables-devel libnfnetlink-devel gcc
No package libnl3-devel available. 可以不要
No package ipset-devel available. 可以不要
No package libnfnetlink-devel available.
[[email protected] ~]# yum install libnfnetlink-devel-1.0.0-1.el6.x86_64.rpm -y

[[email protected] keepalived]# ln -s /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/  
[[email protected] keepalived]# ln -s /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
[[email protected] keepalived]# ln -s /usr/local/keepalived/etc/keepalived/ /etc/
[[email protected] keepalived]# ln -s /usr/local/keepalived/sbin/keepalived /bin/
[[email protected] keepalived]# chmod +x /usr/local/keepalived/etc/rc.d/init.d/keepalived 
[[email protected] keepalived]# /etc/init.d/keepalived status
keepalived is stopped

#slave安裝keepalived可以和源碼相同，也可以使用以下方式
[[email protected] keepalived]# cd /usr/local/
[[email protected] local]# scp -r keepalived/ server4:/usr/local/

[[email protected] ~]# ln -s /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
[[email protected] ~]# ln -s /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
[[email protected] ~]# ln -s /usr/local/keepalived/etc/keepalived/ /etc/
[[email protected] ~]# ln -s /usr/local/keepalived/sbin/keepalived /bin/
[[email protected] ~]# chmod +x /usr/local/keepalived/etc/rc.d/init.d/keepalived

2.master配置

[[email protected] ~]# cd /etc/keepalived/
[[email protected] keepalived]# ls
keepalived.conf  samples
[[email protected] keepalived]# vim keepalived.conf 

global_defs {
　　#當keepalived有動作時發郵件給本機
   notification_email {
     [email protected]
   }
   notification_email_from [email protected]
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
   vrrp_skip_check_adv_addr
   #vrrp_strict    #當參數不被禁止掉時，每次加載keepalived都會給火牆中寫入通路vip的包全部丢棄
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

#高可用子產品
vrrp_instance VI_1 {
    state MASTER  #主，slave配置為BACKUP
    interface eth0
    virtual_router_id 60  #每個人的路由id要不同
    priority 100  #優先級，master的優先級應該高于slave
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.25.60.100
    }
}

#負載均衡(LVS)子產品
virtual_server 172.25.60.100 80 {
    delay_loop 6
    lb_algo rr  #輪叫的排程算法
    lb_kind DR  #LVS模式
    #persistence_timeout 50  #持續連結，需要持續連結的服務要打開該參數
    protocol TCP

    real_server 172.25.60.2 80 {
        weight 1 #權重
        TCP_CHECK{
            connect_timeout 3
            retry 3
            delay_before_retry 3
        }
    }
    real_server 172.25.60.3 80 {
        weight 1
        TCP_CHECK{
            connect_timeout 3
            retry 3
            delay_before_retry 3
        }
    }
}

3.slave配置

[[email protected] keepalived]# scp keepalived.conf server4:
[[email protected] keepalived]# vim 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_DEVEL
   vrrp_skip_check_adv_addr
   #vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 50
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.25.60.100
    }
}

virtual_server 172.25.60.100 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    #persistence_timeout 50
    protocol TCP

    real_server 172.25.60.2 80 {
        weight 1
        TCP_CHECK{
            connect_timeout 3
            retry 3
            delay_before_retry 3
        }
    }

    real_server 172.25.60.3 80 {
        weight 1
        TCP_CHECK{
            connect_timeout 3
            retry 3
            delay_before_retry 3
        }
    }
}

4.安裝ipvsadm

[[email protected] keepalived]# vim /etc/yum.repos.d/rhel-source.repo 
[rhel-source]
name=Red Hat Enterprise Linux $releasever - $basearch - Source
baseurl=http://172.25.60.250/rhel6.5
enabled=1
igpgcheck=0

[HighAvailability]
name=HighAvailability
baseurl=http://172.25.60.250/rhel6.5/HighAvailability
gpgcheck=0

[LoadBalancer]
name=LoadBalancer
baseurl=http://172.25.60.250/rhel6.5/LoadBalancer
gpgcheck=0


[ResilientStorage]
name=ResilientStorage
baseurl=http://172.25.60.250/rhel6.5/ResilientStorage
gpgcheck=0

[ScalableFileSystem]
name=ScalableFileSystem
baseurl=http://172.25.60.250/rhel6.5/ScalableFileSystem
gpgcheck=0
[[email protected] keepalived]# scp /etc/yum.repos.d/rhel-source.repo server4:/etc/yum.repos.d/

[[email protected] keepalived]# yum install ipvsadm -y
[[email protected] keepalived]# /etc/init.d/ipvsadm start
[[email protected] keepalived]# yum install ipvsadm -y
[[email protected] keepalived]# /etc/init.d/ipvsadm start

5.後端伺服器配置

[[email protected] ~]# ip addr add 172.25.60.100 dev eth0
[[email protected] ~]# ip addr add 172.25.60.100 dev eth0

[[email protected] ~]# /etc/init.d/httpd start
[[email protected] ~]# echo server2 > /var/www/html/index.html 
[[email protected] ~]# /etc/init.d/httpd start
[[email protected] ~]# echo server3 > /var/www/html/index.html

6.開啟keepalived并測試

[[email protected] ~]# /etc/init.d/keepalived start
[[email protected] ~]# /etc/init.d/keepalived start

[[email protected] ~]# ipvsadm -l
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  172.25.60.100:http rr
  -> server2:http                 Route   1      0          0         
  -> server3:http                 Route   1      0          0

[[email protected] ~]# ip addr
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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 52:54:00:c0:26:c9 brd ff:ff:ff:ff:ff:ff
    inet 172.25.60.1/24 brd 172.25.60.255 scope global eth0
    inet 172.25.60.100/32 scope global eth0
    inet6 fe80::5054:ff:fec0:26c9/64 scope link 
       valid_lft forever preferred_lft forever

[[email protected] kiosk]# curl 172.25.60.100
server2
[[email protected] kiosk]# curl 172.25.60.100
server3
[[email protected] kiosk]# curl 172.25.60.100
server2
[[email protected] kiosk]# curl 172.25.60.100
server3

#檢測高可用,當master挂掉之後，slave接管所有資源。Master啟動後master重新接管資源。
[[email protected] ~]# /etc/init.d/keepalived stop
Stopping keepalived:                                       [  OK  ]
[[email protected] ~]# ip addr
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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 52:54:00:c0:26:c9 brd ff:ff:ff:ff:ff:ff
    inet 172.25.60.1/24 brd 172.25.60.255 scope global eth0
    inet6 fe80::5054:ff:fec0:26c9/64 scope link 
       valid_lft forever preferred_lft forever
[[email protected] ~]# ipvsadm -l
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
[[email protected] keepalived]# ip addr
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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 52:54:00:91:3e:60 brd ff:ff:ff:ff:ff:ff
    inet 172.25.60.4/24 brd 172.25.60.255 scope global eth0
    inet 172.25.60.100/32 scope global eth0
    inet6 fe80::5054:ff:fe91:3e60/64 scope link 
       valid_lft forever preferred_lft forever
You have new mail in /var/spool/mail/root
[[email protected] keepalived]# ipvsadm -l
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  172.25.60.100:http rr
  -> server2:http                 Route   1      0          0         
  -> server3:http                 Route   1      0          0    
[[email protected] kiosk]# curl 172.25.60.100
server3
[[email protected] kiosk]# curl 172.25.60.100
server2
[[email protected] kiosk]# curl 172.25.60.100
server3
[[email protected] kiosk]# curl 172.25.60.100
server2

#測試負載均衡,keepalived自帶健康檢查
[[email protected] ~]# /etc/init.d/httpd stop
Stopping httpd:                                            [  OK  ]
[[email protected] kiosk]# curl 172.25.60.100
server3
[[email protected] kiosk]# curl 172.25.60.100
server3
[[email protected] kiosk]# curl 172.25.60.100
server3
[[email protected] kiosk]# curl 172.25.60.100
server3
[[email protected] ~]# /etc/init.d/httpd start
Starting httpd: httpd: Could not reliably determine the server's fully qualified domain name, using 172.25.60.3 for ServerName
[[email protected] kiosk]# curl 172.25.60.100
server2
[[email protected] kiosk]# curl 172.25.60.100
server3
[[email protected] kiosk]# curl 172.25.60.100
server2
[[email protected] kiosk]# curl 172.25.60.100
server3
                                                         [  OK  ]

Keepalived實作高可用和負載均衡

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