项目中需要采用tomcat双机热备机制，以确保系统性能。本人通过查阅资料以及亲自实现完成，写下这篇博文，供个人读者参考。
1. 规划
1.1服务器环境规划
负载服务器master及WEB服务器1真实IP：10.10.195.53
负载服务器backup及WEB服务器2真实IP：10.10.195.190
负载服务器虚拟ip：10.10.195.212
1.2 软件环境规划
操作系统：Red Hat Enterprise Linux Server release 5.6 (Tikanga)
keepalived：keepalived-1.2.19
Java：jdk-1.7.0_79
Tomcat：apache-tomcat-7.0.64
2. 负载服务器配置
这里只叙述如何安装配置keepalived，至于java以及tomcat的安装及配置，这里不赘述。
2.1 安装keepalived
[~]tar -zxvf keepalived-1.2.19.tar.gz
[~] cd keepalived-1.2.19
[keepalived-1.2.19] ./configure --prefix=/usr/local/keepalived --disable-fwmark
#(如果直接输入./configure有可能报错：configure:error: No SO_MARK declaration in headers)
[keepalived-1.2.19] make
[keepalived-1.2.19] make install
2.2 配置keepalived服务
[keepalived-1.2.19] cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
[keepalived-1.2.19] cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
[keepalived-1.2.19] cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
[keepalived-1.2.19] mkdir /etc/keepalived
[keepalived-1.2.19] cp /usr/local/keepalived/etc/keepalived/keepalived.conf/etc/keepalived/
[keepalived-1.2.19] chkconfig --add keepalived
[keepalived-1.2.19] chkconfig keepalived on
重启\启动\关闭\查看状态keepalived
service keepalived restart
service keepalived start
service keepalived stop
service keepalived status
2.3 配置keepalived.conf文件
[~]mv /etc/keepalived/keepalived.conf/etc/keepalived/keepalived.conf.bak
[~]vi /etc/keepalived//keepalived.conf
主备机的keepalived.conf文件大致相同，只是注意红色标注的地方。
主机配置：
global_defs {
router_id NodeA
}
vrrp_script chk_http_port {
script "/opt/tomcat.pid"
interval 5
weight 2
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 52
priority 150
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_http_port
}
virtual_ipaddress {
10.10.195.212
}
}
备机配置：
global_defs {
router_id NodeB
}
vrrp_script chk_http_port {
script "/opt/tomcat.pid"
interval 5
weight 2
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_http_port
}
virtual_ipaddress {
10.10.195.212
}
}
2.4配置/opt/tomcat.pid
#!/bin/bash
#description: check tomcat service anddecide whether stop the keepalived or not
#edited by zzh: 2015-10-14
CATALINA_HOME=/users/shr/apache-tomcat-7.0.64
JAVA_HOME=/users/shr/util/JavaDir/jdk
export CATALINA_HOME
export JAVA_HOME
ps ax --width=1000 | grep"org.apache.catalina.startup.Bootstrap start" | grep -v"grep" | awk '{printf $1 " "}' | wc | awk '{print $2}' >tomcat_process_count.txt
read line < tomcat_process_count.txt
start_tomcat=$CATALINA_HOME/bin/startup.sh
if [ ${line} -lt 1 ]
then
echo -n "===Starting tomcat===:"
${start_tomcat}
# :sudo service tomcat start
echo "===tomcat start ok.==="
sleep 3
# check the tomcat status.
ps ax --width=1000 | grep "org.apache.catalina.startup.Bootstrapstart" | grep -v "grep" | awk '{printf $1 " "}' | wc |awk '{print $2}' > tomcat_process_count.txt
read line2 < tomcat_process_count.txt
if [ ${line2} -lt 1 ]
then
sudo service keepalived stop
fi
fi
rm tomcat_process_count.txt
#shell end.
3. 日志查看
3.1 正常启动
输入tail -f /var/log/messages查看启动keepalived日志：
（MASTER：10.10.195.53）
Sep 29 15:49:16 shr Keepalived[5536]:Starting Keepalived v1.2.19 (09/21,2015)
Sep 29 15:49:16 shrKeepalived_healthcheckers[5538]: Netlink reflector reports IP 10.10.195.53added
Sep 29 15:49:16 shrKeepalived_healthcheckers[5538]: Netlink reflector reports IP 10.10.195.53added
Sep 29 15:49:16 shrKeepalived_healthcheckers[5538]: Registering Kernel netlink reflector
Sep 29 15:49:16 shrKeepalived_healthcheckers[5538]: Registering Kernel netlink command channel
Sep 29 15:49:16 shrKeepalived_healthcheckers[5538]: Opening file'/etc/keepalived/keepalived.conf'.
Sep 29 15:49:16 shrKeepalived_healthcheckers[5538]: Configuration is using : 6572 Bytes
Sep 29 15:49:16 shr Keepalived[5537]:Starting Healthcheck child process, pid=5538
Sep 29 15:49:16 shr Keepalived_healthcheckers[5538]:Using LinkWatch kernel netlink reflector...
Sep 29 15:49:16 shr Keepalived_vrrp[5539]:Netlink reflector reports IP 10.10.195.53 added
Sep 29 15:49:16 shr Keepalived_vrrp[5539]:Netlink reflector reports IP 10.10.195.53 added
Sep 29 15:49:16 shr Keepalived[5537]:Starting VRRP child process, pid=5539
Sep 29 15:49:16 shr Keepalived_vrrp[5539]:Registering Kernel netlink reflector
Sep 29 15:49:16 shr Keepalived_vrrp[5539]:Registering Kernel netlink command channel
Sep 29 15:49:16 shr Keepalived_vrrp[5539]:Registering gratuitous ARP shared channel
Sep 29 15:49:16 shr Keepalived_vrrp[5539]:Opening file '/etc/keepalived/keepalived.conf'.
Sep 29 15:49:16 shr Keepalived_vrrp[5539]:Configuration is using : 36541 Bytes
Sep 29 15:49:16 shr Keepalived_vrrp[5539]:Using LinkWatch kernel netlink reflector...
Sep 29 15:49:16 shr Keepalived_vrrp[5539]:VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]
Sep 29 15:49:17 shr Keepalived_vrrp[5539]:VRRP_Instance(VI_1) Transition to MASTER STATE
Sep 29 15:49:17 shr Keepalived_vrrp[5539]:VRRP_Instance(VI_1) Received lower prio advert, forcing new election
Sep 29 15:49:18 shr Keepalived_vrrp[5539]:VRRP_Instance(VI_1) Entering MASTER STATE
Sep 29 15:49:18 shr Keepalived_vrrp[5539]:VRRP_Instance(VI_1) setting protocol VIPs.
Sep 29 15:49:18 shr Keepalived_vrrp[5539]:VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 10.10.195.212
Sep 29 15:49:18 shr Keepalived_vrrp[5539]:Netlink reflector reports IP 10.10.195.212 added
Sep 29 15:49:18 shrKeepalived_healthcheckers[5538]: Netlink reflector reports IP 10.10.195.212added
Sep 29 15:49:23 shr Keepalived_vrrp[5539]:VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 10.10.195.212
(BACKUP:10.10.195.190)
Sep 29 15:46:25 server1 Keepalived[18218]:Starting Keepalived v1.2.19 (09/25,2015)
Sep 29 15:46:25 server1Keepalived_healthcheckers[18220]: Netlink reflector reports IP 10.10.195.190added
Sep 29 15:46:25 server1Keepalived_healthcheckers[18220]: Netlink reflector reports IP 10.10.195.190added
Sep 29 15:46:25 server1Keepalived_healthcheckers[18220]: Registering Kernel netlink reflector
Sep 29 15:46:25 server1Keepalived_healthcheckers[18220]: Registering Kernel netlink command channel
Sep 29 15:46:25 server1 Keepalived_healthcheckers[18220]:Opening file '/etc/keepalived/keepalived.conf'.
Sep 29 15:46:25 server1Keepalived_healthcheckers[18220]: Configuration is using : 6682 Bytes
Sep 29 15:46:25 server1 Keepalived[18219]:Starting Healthcheck child process, pid=18220
Sep 29 15:46:25 server1 Keepalived[18219]:Starting VRRP child process, pid=18221
Sep 29 15:46:25 server1Keepalived_vrrp[18221]: Netlink reflector reports IP 10.10.195.190 added
Sep 29 15:46:25 server1Keepalived_vrrp[18221]: Netlink reflector reports IP 10.10.195.190 added
Sep 29 15:46:25 server1Keepalived_healthcheckers[18220]: Using LinkWatch kernel netlink reflector...
Sep 29 15:46:25 server1Keepalived_vrrp[18221]: Registering Kernel netlink reflector
Sep 29 15:46:25 server1Keepalived_vrrp[18221]: Registering Kernel netlink command channel
Sep 29 15:46:25 server1Keepalived_vrrp[18221]: Registering gratuitous ARP shared channel
Sep 29 15:46:25 server1Keepalived_vrrp[18221]: Opening file '/etc/keepalived/keepalived.conf'.
Sep 29 15:46:25 server1 Keepalived_vrrp[18221]:Configuration is using : 36651 Bytes
Sep 29 15:46:25 server1Keepalived_vrrp[18221]: Using LinkWatch kernel netlink reflector...
Sep 29 15:46:25 server1Keepalived_vrrp[18221]: VRRP_Instance(VI_1) Entering BACKUP STATE
Sep 29 15:46:25 server1 Keepalived_vrrp[18221]:VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]
3.2 主备切换
l 当在主机（MASTER：10.10.195.53）中输入 sudoservice keepalived stop，此时就会进行主备切换，主机切换成备机。
主机（MASTER：10.10.195.53）输出如下
Oct 14 13:25:09 shr Keepalived_vrrp[26683]:VRRP_Instance(VI_1) sending 0 priority
Oct 14 13:25:09 shr Keepalived_vrrp[26683]:VRRP_Instance(VI_1) removing protocol VIPs.
Oct 14 13:25:09 shrKeepalived_healthcheckers[26682]: Netlink reflector reports IP 10.10.195.212removed
Oct 14 13:25:09 shr Keepalived[26681]:Stopping Keepalived v1.2.19 (09/21,2015)
备机(BACKUP:10.10.195.190)输出如下
Oct 14 13:19:58 server1Keepalived_vrrp[30890]: VRRP_Instance(VI_1) Transition to MASTER STATE
Oct 14 13:19:59 server1Keepalived_vrrp[30890]: VRRP_Instance(VI_1) Entering MASTER STATE
Oct 14 13:19:59 server1Keepalived_vrrp[30890]: VRRP_Instance(VI_1) setting protocol VIPs.
Oct 14 13:19:59 server1Keepalived_vrrp[30890]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for10.10.195.212
Oct 14 13:19:59 server1 Keepalived_healthcheckers[30889]:Netlink reflector reports IP 10.10.195.212 added
Oct 14 13:19:59 server1Keepalived_vrrp[30890]: Netlink reflector reports IP 10.10.195.212 added
Oct 14 13:20:04 server1Keepalived_vrrp[30890]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for10.10.195.212
l 当在主机（MASTER：10.10.195.53）中输入sudoservice keepalived start,此时就会切换成主机。备机(BACKUP:10.10.195.190)输出如下信息：
Oct 14 13:25:11 server1Keepalived_vrrp[30890]: VRRP_Instance(VI_1) Received higher prio advert
Oct 14 13:25:11 server1Keepalived_vrrp[30890]: VRRP_Instance(VI_1) Entering BACKUP STATE
Oct 14 13:25:11 server1Keepalived_vrrp[30890]: VRRP_Instance(VI_1) removing protocol VIPs.
Oct 14 13:25:11 server1Keepalived_healthcheckers[30889]: Netlink reflector reports IP 10.10.195.212removed
Oct 14 13:25:11 server1Keepalived_vrrp[30890]: Netlink reflector reports IP 10.10.195.212 removed
4. 查看虚拟ip
可以通过ip add show命令查看添加的虚拟ip：
[shr@shr bin]$ip add show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu16436 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
2: eth0:<BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:6b:f2:a8 brd ff:ff:ff:ff:ff:ff
inet 10.10.195.53/24 brd 10.10.195.255 scope global eth0
inet 10.10.195.212/32scope global eth0
5. 常见错误
5. 1常见错误一：
/var/log/messages has thousands of errorslike this:
Jun 28 09:18:32 rust Keepalived_vrrp:receive an invalid ip number count
associated with VRID!
Jun 28 09:18:32 rust Keepalived_vrrp: bogusVRRP packet received on eth0 !!!
Jun 28 09:18:32 rust Keepalived_vrrp:VRRP_Instance(VI_1) Dropping received
VRRP packet...
The backup director starts up, but doesn'tlisten on the virtual addresses
at all. Its /var/log/messages has thousands of errors like this:
Jun 28 06:25:05 stye Keepalived_vrrp:receive an invalid ip number count
associated with VRID!
Jun 28 06:25:05 stye Keepalived_vrrp: bogusVRRP packet received on eth0 !!!
Jun 28 06:25:05 stye Keepalived_vrrp:VRRP_Instance(VI_1) ignoring received
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解决方法：
改变配置文件/etc/keepalived/keepalived.conf中virtual_router_id为另一个值即可。
（changed the vrid to another number and it worked fine）.
5.2 常见错误二：
主机执行到VRRP_Instance(VI_1) Entering BACKUP STATE之后没有执行VRRP_Instance(VI_1)setting protocol VIPs。
解决方法：
可能是配置文件keepalived.conf中{左边没有空格。
附
linux添加tomcat服务
在/etc/init.d中输入 sudo vim tomcat
脚本具体内容如下：
#!/bin/bash
#chkconfig: 2345 10 90
#description: Starts and Stops the tomcatdaemon
#edited by ZZH: 2015-10-14
CATALINA_HOME=/users/shr/apache-tomcat-7.0.64
JAVA_HOME=/users/shr/util/JavaDir/jdk
export CATALINA_HOME
export JAVA_HOME
start_tomcat=$CATALINA_HOME/bin/startup.sh
stop_tomcat=$CATALINA_HOME/bin/shutdown.sh
if [ ! -f $CATALINA_HOME/bin/catalina.sh ]
then
echo"===Tomcat is not available.==="
exit
fi
start()
{
echo-n "===Starting tomcat===:"
${start_tomcat}
echo"===tomcat start ok.==="
}
stop()
{
echo-n "===Shutting down tomcat===:"
${stop_tomcat}
echo"===tomcat stop ok.==="
}
status()
{
ps ax --width=1000 | grep"org.apache.catalina.startup.Bootstrap start" | grep -v"grep" | awk '{printf $1 " "}' | wc | awk '{print $2}'> tomcat_process_count.txt
readline < tomcat_process_count.txt
rmtomcat_process_count.txt
if[ $line -gt 0 ]
then
echo-n "tomcat ( pid = "
ps ax --width=1000 | grep"org.apache.catalina.startup.Bootstrap start" | grep -v"grep" | awk '{printf $1 " "}' | awk '{print $1}'> tomcat_process_pid.txt
readpid < tomcat_process_pid.txt
rmtomcat_process_pid.txt
echo-n $pid
echo-n ") is running..."
echo
else
echo"tomcat is stopped"
fi
}
case "$1" in
start)
start
;;
stop)
stop
;;
restart)
stop
sleep1
start
;;
status)
status
;;
*)
echo"Usage:$0 {start|stop|restart}"
exit1
esac
exit 0
# shell end.
在终端输入:
sudo chmod 755 tomcat
sudo chkconfig --add tomcat
tomcat 启动 service tomcatstart
tomcat 关闭 service tomcatstop
tomcat 重启 service tomcatrestart
tomcat状态查看 service tomcatstatus