负载均衡实战之二：故障隔离攻略

　　三、keepalived 安装验证

　　Keepalived安装完成后，会在安装目录/usr/local/keepalived生成 bin,etc,man,sbin这4个目录。其中etc为配置文件所在的目录，进入这个目录，看看里面都有些什么?

　　[root@ChinaTelecom-1 etc]# pwd

　　/usr/local/keepalived/etc

　　[root@ChinaTelecom-1 etc]# ll

　　total 12

　　drwxr-xr-x 3 root root 4096 Apr 23 10:23 keepalived

　　drwxr-xr-x 3 root root 4096 Apr 23 10:23 rc.d

　　drwxr-xr-x 2 root root 4096 Apr 23 10:23 sysconfig

　　还有子目录，这里着重关注一下keepalived目录，它的下面包含一个完整的配置文件keepalived.conf(实际上是一个样例)以及一些单独的配置样例文件。

　　[root@ChinaTelecom-1 keepalived]# tree -l

　　.

　　|-- keepalived.conf

　　`-- samples

　　|-- client.pem

　　|-- dh1024.pem

　　|-- keepalived.conf.HTTP_GET.port

　　|-- keepalived.conf.SMTP_CHECK

　　|-- keepalived.conf.SSL_GET

　　|-- keepalived.conf.fwmark

　　|-- keepalived.conf.inhibit

　　|-- keepalived.conf.misc_check

　　|-- keepalived.conf.misc_check_arg

　　|-- keepalived.conf.sample

　　|-- keepalived.conf.status_code

　　|-- keepalived.conf.track_interface

　　|-- keepalived.conf.virtual_server_group

　　|-- keepalived.conf.virtualhost

　　|-- keepalived.conf.vrrp

　　|-- keepalived.conf.vrrp.localcheck

　　|-- keepalived.conf.vrrp.lvs_syncd

　　|-- keepalived.conf.vrrp.routes

　　|-- keepalived.conf.vrrp.scripts

　　|-- keepalived.conf.vrrp.static_ipaddress

　　|-- keepalived.conf.vrrp.sync

　　|-- root.pem

　　`-- sample.misccheck.smbcheck.sh

　　值得注意的是，keepalived的启动过程并不会对配置文件进行语法检查，就算没有配置文件，keepalived的守护进程照样能够被运行起来。在默认状态下--即不指定配置文件的位置-keepalived先查找文件 /etc/keepalived/keepalived.conf ，如果为了省事，可以手动创建这个文件，然后在这个文件里书写规则，来达到控制keepalived运行的目的。

　　这里我们先来试试默认情况，即没有配置文件下运行keepalived.运行前先了解一下其语法：

　　[root@lvs-m keepalived]# keepalived --help

　　Keepalived v1.1.17 (06/23,2009)

　　Usage:

　　keepalived

　　keepalived -n

　　keepalived -f keepalived.conf

　　keepalived -d

　　keepalived -h

　　keepalived -v

　　Commands:

　　Either long or short options are allowed.

　　keepalived --vrrp -P Only run with VRRP subsystem.

　　keepalived --check -C Only run with Health-checker subsystem.

　　keepalived --dont-release-vrrp -V Dont remove VRRP VIPs & VROUTEs on daemon stop.

　　keepalived --dont-release-ipvs -I Dont remove IPVS topology on daemon stop.

　　keepalived --dont-fork -n Dont fork the daemon process.

　　keepalived --use-file -f Use the specified configuration file.

　　Default is /etc/keepalived/keepalived.conf.

　　keepalived --dump-conf -d Dump the configuration data.

　　keepalived --log-console -l Log message to local console.

　　keepalived --log-detail -D Detailed log messages.

　　keepalived --log-facility -S 0-7 Set syslog facility to LOG_LOCAL[0-7]. (default=LOG_DAEMON)

　　keepalived --help -h Display this short inlined help screen.

　　keepalived --version -v Display the version number

　　keepalived --pid -p pidfile

　　keepalived --checkers_pid -c checkers pidfile

　　keepalived --vrrp_pid -r vrrp pidfile

　　接下来我们参照这个帮助语法，执行命令 /usr/local/keepalived/sbin/keepalive -D ,然后来检查keepalived运行后的状况。

　　1、 查看进程 ps aux | grep keepalived ，其输出为：

　　[root@lvs-m ~]# ps aux| grep keepalived |grep -v grep

　　root 21786 0.0 0.0 4840 564 ? Ss 15:39 0:00 keepalived -D

　　root 21787 4.8 0.0 4884 1336 ? S 15:39 23:47 keepalived -D

　　root 21788 4.9 0.0 4884 904 ? S 15:39 24:15 keepalived -D

　　Keepalived正常运行时，共启动3个进程，其中一个进程是父进程，负责监控其子进程;一个是vrrp子进程;另外一个是checkers子进程。图2 为keepalived 3个进程之间的关系。

　　图2keepalived进程相关性

　　2、 查看内核模块，ip_vs 模块应该被加载到内核空间。 Lsmod | grep ip_vs .

　　3、 查看系统日志。因为我在启动keepalived是使用了选项 -D ,这将详细的打印日志消息。

　　[root@lvs-m ~]# tail -f /var/log/messages

　　Jun 27 00:58:05 lvs-m Keepalived: Starting VRRP child process, pid=22017

　　Jun 27 00:58:05 lvs-m Keepalived_healthcheckers: Netlink reflector reports IP 61.135.20.137 added

　　Jun 27 00:58:05 lvs-m Keepalived_healthcheckers: Registering Kernel netlink reflector

　　Jun 27 00:58:05 lvs-m Keepalived_vrrp: Netlink reflector reports IP 61.135.20.137 added

　　Jun 27 00:58:05 lvs-m Keepalived_healthcheckers: Registering Kernel netlink command channel

　　Jun 27 00:58:05 lvs-m Keepalived_vrrp: Registering Kernel netlink reflector

　　Jun 27 00:58:05 lvs-m Keepalived_vrrp: Registering Kernel netlink command channel

　　Jun 27 00:58:05 lvs-m Keepalived_vrrp: Registering gratutious ARP shared channel

　　Jun 27 00:58:05 lvs-m Keepalived_healthcheckers: Configuration is using : 2285 Bytes

　　Jun 27 00:58:05 lvs-m Keepalived_vrrp: Configuration is using : 28803 Bytes

　　逐项检查这个输出，可知图1所示的组件都可以在这里找到对应的纪录。从而进一步证实keepalived安装的正确性。