做mysql的slave监控的时候，需要check_mysql脚本，check的时候报错：
 error while loading shared libraries: libmysqlclient.so.18: cannot open shared object file: No such file or directory

1，错误信息如下：
[root@slave ~]# /usr/local/nagios/libexec/check_mysql -uadmin -P3306 -S /data/mbdata/open/mysql.sock -H127.0.0.1 -pxxxxx -d openshop -w 300 -c 360
/usr/local/nagios/libexec/check_mysql: error while loading shared libraries: libmysqlclient.so.18: cannot open shared object file: No such file or directory
[root@slave ~]#

2，执行check_mysql --help看下命令，发现也不行。

[root@slave ~]# /usr/local/nagios/libexec/check_mysql --help
/usr/local/nagios/libexec/check_mysql: error while loading shared libraries: libmysqlclient.so.18: cannot open shared object file: No such file or directory
[root@slave ~]# 

3，查看一下报错的libmysqlclient.so.18文件是否存在：
[root@db-m1-slave-1 ~]# find / -name libmysqlclient.so.18
/mysql-5.6.12/libmysql/libmysqlclient.so.18
/usr/local/mysql/lib/libmysqlclient.so.18
文件存在，但是无法识别。

4，可能是libmysqlclient的问题
搜索mysqlclient library linkage problem。
找到文章地址：http://stackoverflow.com/questions/2080679/mysqlclient-library-linkage-problem
发现有/etc/ld.so.conf.d/mysql-x86_64.conf这样一个配置文件，打开看看
cat /etc/ld.so.conf.d/mysql-x86_64.conf

[root@slave ~]# cat /etc/ld.so.conf.d/mysql-x86_64.conf
/usr/lib64/mysql

进入目录/usr/lib64/mysql查看下有什么文件：
[root@slave ~]# ll /usr/lib64/mysql
总用量 3108
lrwxrwxrwx. 1 root root      26 9月  29 2013 libmysqlclient_r.so.16 -> libmysqlclient_r.so.16.0.0
-rwxr-xr-x. 1 root root 1595176 12月  8 2012 libmysqlclient_r.so.16.0.0
lrwxrwxrwx. 1 root root      24 9月  29 2013 libmysqlclient.so.16 -> libmysqlclient.so.16.0.0
-rwxr-xr-x. 1 root root 1582952 12月  8 2012 libmysqlclient.so.16.0.0
有一些软连接，而且带了后缀表示so.16之类的，但是没有so.18之类，看来是没有连接到这里，
可能是需要做一个软连接把/usr/local/mysql/lib/libmysqlclient.so.18变成/usr/lib64/libmysqlclient.so.18，
马上去做软连接：ln -s /usr/local/mysql/lib/libmysqlclient.so.18 /usr/lib64/libmysqlclient.so.18，然后再check下。

[root@slave ~]# ln -s /usr/local/mysql/lib/libmysqlclient.so.18 /usr/lib64/libmysqlclient.so.18
[root@slave ~]# 
[root@slave ~]# 
[root@slave ~]# /usr/local/nagios/libexec/check_mysql --help
check_mysql v2.0 (nagios-plugins 2.0)
Copyright (c) 1999-2014 Nagios Plugin Development Team
	
This program tests connections to a MySQL server
Usage:
 check_mysql [-d database] [-H host] [-P port] [-s socket]
       [-u user] [-p password] [-S] [-l] [-a cert] [-k key]
       [-C ca-cert] [-D ca-dir] [-L ciphers] [-f optfile] [-g group]


Options:
 -h, --help
    Print detailed help screen
 -V, --version
    Print version information
 --extra-opts=[section][@file]
    Read options from an ini file. See
    https://www.nagios-plugins.org/doc/extra-opts.html
    for usage and examples.
..................................
-l, --ssl
    Use ssl encryptation
 -C, --ca-cert=STRING
    Path to CA signing the cert
 -a, --cert=STRING
    Path to SSL certificate
 -k, --key=STRING
    Path to private SSL key
 -D, --ca-dir=STRING
    Path to CA directory
 -L, --ciphers=STRING
    List of valid SSL ciphers
.................................................
Send email to help@nagios-plugins.org if you have questions regarding use
of this software. To submit patches or suggest improvements, send email to
devel@nagios-plugins.org


[root@slave ~]# 

5，继续执行check_mysql来check一下
[root@slave ~]# /usr/local/nagios/libexec/check_mysql -unagios -P3306 -S -H127.0.0.1 --password='xxx@0512' /usr/local/mysql/mysql.sock -d test -w 60 -c 100
slave query error: Access denied; you need (at least one of) the SUPER, REPLICATION CLIENT privilege(s) for this operation
[root@slave ~]# 
报账号错误，
check
slave query error: Access denied; you need (at least one of) the SUPER, REPLICATION CLIENT privilege(s) for this operation
账号错误，进入mysql界面赋予nagios账号权限
mysql> GRANT PROCESS, SUPER, REPLICATION CLIENT ON *.* TO nagios@'%' identified by 'xxx@0512';

6，再check
[root@slave ~]# /usr/local/nagios/libexec/check_mysql -unagios -P3306 -S -Hlocalhost --password='xxx@0512' -s /usr/local/mysql/mysql.sock -d test -w 60 -c 100
Slave IO: Yes Slave SQL: No Seconds Behind Master: (null)

mysql slave 检测失败，有错误信息：Slave IO: Yes Slave SQL: No Seconds Behind Master: (null)

进mysql窗口去看详细信息:

[root@slave ~]# mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 23
Server version: 5.6.12-log Source distribution

Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 10.xx.3.xx
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.010294
          Read_Master_Log_Pos: 21764
               Relay_Log_File: mysql-relay-bin.003125
                Relay_Log_Pos: 91805
        Relay_Master_Log_File: mysql-bin.010275
             Slave_IO_Running: Yes
            Slave_SQL_Running: No
              Replicate_Do_DB: xx,xx_db,xxsystem
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 1590
                   Last_Error: The incident LOST_EVENTS occured on the master. Message: error writing to the binary log
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 91642
              Relay_Log_Space: 1780004
              Until_Condition: None
               Until_Log_File: 
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File: 
           Master_SSL_CA_Path: 
              Master_SSL_Cert: 
            Master_SSL_Cipher: 
               Master_SSL_Key: 
        Seconds_Behind_Master: NULL
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 1590
               Last_SQL_Error: The incident LOST_EVENTS occured on the master. Message: error writing to the binary log
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 71
                  Master_UUID: 9b0dcf62-29f4-11e3-9471-677b33903869
             Master_Info_File: mysql.slave_master_info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: 
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 140512 11:29:54
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
1 row in set (0.00 sec)
mysql> 

关于Slave IO: Yes Slave SQL: No Seconds Behind Master: (null)，参考blog： http://blog.csdn.net/mchdba/article/details/25738991 

7，slave重做之后，再check，slave状态是正常的。

# /usr/local/nagios/libexec/check_mysql -unagios -P3306 -S -s /usr/local/mysql/mysql.sock -Hlocalhost --password='xxx@0512' -d test -w 60 -c 100 

[root@slave ~]# /usr/local/nagios/libexec/check_mysql -unagios -P3306 -S -s /usr/local/mysql/mysql.sock -Hlocalhost --password='xxx@0512' -d test -w 60 -c 100 
Uptime: 18431321  Threads: 3  Questions: 1447646  Slow queries: 735  Opens: 18605  Flush tables: 1  Open tables: 214  Queries per second avg: 0.078 Slave IO: Yes Slave SQL: Yes Seconds Behind Master: 0|Connections=1380c;;; Open_files=32;;; Open_tables=214;;; Qcache_free_memory=66980240;;; Qcache_hits=778c;;; Qcache_inserts=5338c;;; Qcache_lowmem_prunes=0c;;; Qcache_not_cached=12516c;;; Qcache_queries_in_cache=34;;; Queries=1447647c;;; Questions=99727c;;; Table_locks_waited=0c;;; Threads_connected=1;;; Threads_running=1;;; Uptime=18431321c;;; 'seconds behind master'=0.000000s;60.000000;100.000000;
[root@db-m1-slave-1 ~]#