keepalived是一個用於做雙機熱備（HA）的軟件，常和haproxy聯合起來做熱備＋負載均衡，達到高可用
1. 實驗環境
Master:10.20.2.233
Backup:10.20.2.235
虛擬IP:10.20.2.238
2. Keepalived安裝
1) 通過yum安裝軟件依賴包
yum install -y wget make gcc openssl-devel popt-devel
2) Keepalived源碼包下載安裝
下載地址：http://www.keepalived.org/software/keepalived-1.2.23.tar.gz
tar -zxf keepalived-1.2.23.tar.gz -C /usr/src cd /sru/src/keepalived-1.2.23/ ./configure --prefix=/usr/local/keepalived/ Make make install
3) 安裝成功後做成服務模式
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/
3. 編輯配置文件
mkdir -p /etc/keepalived cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
1) Master配置文件內容如下：
! Configuration File for keepalived
global_defs {
router_id HA_TEST
}
#監測haproxy進程狀態，每2秒執行一次
vrrp_script chk_haproxy {
script "/etc/keepalived/check_haproxy.sh"
interval 2
weight 2
}
vrrp_instance VI_1 {
state MASTER # 從爲BACKUP
priority 200 # 從爲100
virtual_router_id 51 #路由ID，可通過#tcpdump vrrp查看。
garp_master_delay 1 #主從切換時間，單位爲秒。
interface eth0
advert_int 1
mcast_src_ip 10.20.2.233 #MASTER服務器IP,從服務器寫從服務器的IP
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.20.2.238 #虛擬IP
}
track_script {
chk_haproxy #監測haproxy進程狀態
}
}2) BACKUP配置文件內容如下：
! Configuration File for keepalived
global_defs {
router_id HA_TEST
}
#監測haproxy進程狀態，每2秒執行一次
vrrp_script chk_haproxy {
script "/etc/keepalived/check_haproxy.sh"
interval 2
weight 2
}
vrrp_instance VI_1 {
state BACKUP # 主爲MASTER
priority 100 # 主爲101
virtual_router_id 51 #路由ID，可通過#tcpdump vrrp查看。
garp_master_delay 1 #主從切換時間，單位爲秒。
interface eth0
advert_int 1
mcast_src_ip 10.20.2.235 #BACKUP服務器IP,主服務器寫主服務器的IP
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.20.2.238 #虛擬IP
}
track_script {
chk_haproxy #監測haproxy進程狀態
}
}3) haproxy檢測腳本（check_haproxy.sh）內容如下
#!/bin/bash A=`ps -C haproxy --no-header |wc -l` if [ $A -eq 0 ];then /etc/init.d/haproxyd start sleep 3 if [ `ps -C haproxy --no-header |wc -l` -eq 0 ];then /etc/init.d/keepalived stop fi Fi chmod 755 /etc/keepalived/check_haproxy.sh #腳本編寫完成後需要賦上權限
4) Keepalived的啓停
service keepalived start #停止 service keepalived stop #啓動 service keepalived restart #重啓
4. 測試：
1) 啓動MASTER和BACKUP上的keepalived
service keepalived start （keepalived啓動的同時會將haproxy啓動） [root@test keepalived]# service keepalived start Starting keepalived: [ OK ] [root@test keepalived]# service haproxyd status HAProxy(pid 32077) is running!
MASTER綁定了VIP,BACKUP未綁定VIP
[root@test keepalived]# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 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 00:50:56:85:46:b2 brd ff:ff:ff:ff:ff:ff inet 10.20.2.233/24 brd 10.20.2.255 scope global eth0 inet 10.20.2.238/32 scope global eth0 inet6 fe80::250:56ff:fe85:46b2/64 scope link valid_lft forever preferred_lft forever [root@dengqp01 keepalived]# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 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 00:50:56:85:73:ce brd ff:ff:ff:ff:ff:ff inet 10.20.2.235/24 brd 10.20.2.255 scope global eth0 inet6 fe80::250:56ff:fe85:73ce/64 scope link valid_lft forever preferred_lft forever
2) 停止主上的haproxy，3秒後，keepalived會將其啓動
[root@test keepalived]# service haproxyd stop STOP HAProxy Listen STOP HAProxy process [root@test keepalived]# service haproxyd status HAProxy(pid 32368) is running!
3) 停止主上的keepalived，備機馬上接管服務
BACKUP上綁定了VIP
[root@dengqp01 keepalived]# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 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 00:50:56:85:73:ce brd ff:ff:ff:ff:ff:ff inet 10.20.2.235/24 brd 10.20.2.255 scope global eth0 inet 10.20.2.238/32 scope global eth0 inet6 fe80::250:56ff:fe85:73ce/64 scope link valid_lft forever preferred_lft forever
4) 啓動主上的keepalived，MASTER綁定VIP，BACKUP釋放了VIP
[root@test keepalived]# service keepalived start Starting keepalived: [ OK ] [root@dengqp01 keepalived]# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 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 00:50:56:85:73:ce brd ff:ff:ff:ff:ff:ff inet 10.20.2.235/24 brd 10.20.2.255 scope global eth0 inet 10.20.2.238/32 scope global eth0 inet6 fe80::250:56ff:fe85:73ce/64 scope link valid_lft forever preferred_lft forever