Cacti监控MySQL实现过程中碰到的问题解汇总

浏览数：51 / 时间：2015年06月12日

前言：cacti监控mysql服务器的大概50张graphs都弄出来了，也出图了，其中遇到一些问题，印象比较深刻的记录如下：

（一）：添加io监控

点击Create Graphs for this Host 进去创建IO的图，结果报错

This data query returned 0 rows, perhaps there was a problem executing this data query. You can run this data query in debug mode to get more information.

进入*Turn On Graph Debug Mode模式，报错如下：

RRDTool Command:

/usr/bin/rrdtool graph - \

--imgformat=PNG \

--start=-86400 \

--end=-300 \

--title=‘db-m2-slave-1 - Traffic‘ \

--rigid \

--base=1000 \

--height=120 \

--width=500 \

--alt-autoscale-max \

--lower-limit=‘0‘ \

--vertical-label=‘bits per second‘ \

--slope-mode \

--font TITLE:10: \

--font AXIS:7: \

--font LEGEND:8: \

--font UNIT:7: \

CDEF:cdefa=‘a,8,*‘ \

AREA:cdefa#00CF00FF:‘Inbound‘ \

GPRINT:cdefa:LAST:‘ Current\:%8.2lf %s‘ \

GPRINT:cdefa:AVERAGE:‘Average\:%8.2lf %s‘ \

GPRINT:cdefa:MAX:‘Maximum\:%8.2lf %s\n‘ \

LINE1:cdefa#002A97FF:‘Outbound‘ \

GPRINT:cdefa:LAST:‘Current\:%8.2lf %s‘ \

GPRINT:cdefa:AVERAGE:‘Average\:%8.2lf %s‘ \

GPRINT:cdefa:MAX:‘Maximum\:%8.2lf %s\n‘

RRDTool Says:

ERROR: invalid rpn expression in: a,8,*，如下图所示

编辑linux主机下的/etc/snmp/snmpd.conf文件
找到：com2sec notConfigUser default       public
修改成：com2sec notConfigUser all       public
找到：access notConfigGroup ""      any       noauth    exact systemview none none
修改成：access notConfigGroup ""      any       noauth    exact all none none
找到：#view all    included .1     80把该行的#去掉,
找到：#view mib2   included .iso.org.dod.internet.mgmt.mib-2 fc 把改行的#去掉,
重起snmpd：/etc/init.d/snmpd restart

（二）：MySQL添加主机出不来图

[root@squid-2 test]# service httpd restart

停止 httpd： [确定]

正在启动 httpd：httpd: Could not reliably determine the server‘s fully qualified domain name, using 127.0.0.1 for ServerName

[确定]

1）进入配置文件目录

cd /etc/httpd/conf/

2）编辑httpd.conf文件，搜索"#ServerName"，添加ServerName localhost:80
[root@server conf]# ls
extra httpd.conf magic mime.types original
[root@server conf]# vi httpd.conf
#ServerName www.example.com:80
ServerName localhost:80
3）再重新启动apache 即可。

（三）：启动报错

[root@squid-2 error]# tail -f /var/log/httpd/error_log

[Sat May 31 22:49:02 2014] [notice] caught SIGTERM, shutting down

[Sat May 31 22:49:02 2014] [notice] SELinux policy enabled; httpd running as context unconfined_u:system_r:httpd_t:s0

[Sat May 31 22:49:02 2014] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)

[Sat May 31 22:49:02 2014] [notice] Digest: generating secret for digest authentication ...

[Sat May 31 22:49:02 2014] [notice] Digest: done

[Sat May 31 22:49:02 2014] [notice] Apache/2.2.15 (Unix) DAV/2 PHP/5.3.3 configured -- resuming normal operations

解决方法：直接关闭SELinux以及防火墙

（四）：MySQL监控项出图报错

[Sat May 31 23:20:10 2014] [error] [client 192.168.171.71] PHP Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 523800 bytes) in /var/www/html/cacti/lib/adodb/adodb.inc.php on line 833

需要导入cacti.sql文件

mysql -u root -p cacti < /var/www/html/cacti/cacti.sql

（五）：SNMP – Interface Statistics报错

创建SNMP – Interface Statistics报错，如下：

Created graph: db-m2-slave-2 - Traffic - |query_ifName|

ERROR: no Data Source associated. Check Template

[root@squid-2 html]# snmpwalk -c public -v 2c 10.254.3.73 ifHCInOctets

IF-MIB::ifHCInOctets = No more variables left in this MIB View (It is past the end of the MIB tree)

[root@squid-2 html]#

[root@squid-2 html]# snmpwalk -c public -v 2c 10.254.3.73 if

IF-MIB::ifTable = No Such Object available on this agent at this OID

于是再次修改snmpd.conf,并重启snmpd
access notConfigGroup "" any noauth exact systemview none none-->
access notConfigGroup "" any noauth exact all none none

[root@db-m2-slave-2 ~]# service snmpd restart

停止 snmpd： [确定]

正在启动 snmpd： [确定]

[root@db-m2-slave-2 ~]#

[root@squid-2 html]# snmpwalk -c public -v 2c 10.254.3.73 if

IF-MIB::ifTable = No more variables left in this MIB View (It is past the end of the MIB tree)

【】解决

在snmpd.conf配置文件里面，查找以下字段：[/color]

## incl/excl subtree mask

#view all included .1 80

将该行前面的"#"去掉.

之后重启snmpd服务解决。

报错（六）：

移除出错的图

进去Consoleà Graph Management àHost(选择出错的主机地址)—>Search(搜索报错的关键字Used Space)，就会找到报错不出错的Graph Title栏目，勾选右侧的全选框，点击Go按钮删除掉这些无效的图即可，如下图所示：

然后在新出来的提示界面，点击Continue按钮，删除。

（七）：Memory Free值为nan

分析：memery free 无数据，原因： rrdtool 的内存上限为10G。

[root@squid-2 local]# find / -name *mem*.rrd

/var/www/html/cacti/rra/db-m2-slave-1_mem_buffers_189.rrd

/var/www/html/cacti/rra/db-master-2_mem_free_156.rrd

/var/www/html/cacti/rra/db-m2-slave-1_lock_system_memory_20.rrd

/var/www/html/cacti/rra/db-m2-slave-2_total_mem_alloc_74.rrd

/var/www/html/cacti/rra/db-m2-slave-1_total_mem_alloc_23.rrd

/var/www/html/cacti/rra/db-m2-slave-2_lock_system_memory_71.rrd

/var/www/html/cacti/rra/localhost_mem_swap_4.rrd

/var/www/html/cacti/rra/db-master-2_total_mem_alloc_117.rrd

/var/www/html/cacti/rra/db-master-2_mem_cache_155.rrd

/var/www/html/cacti/rra/db-master-2_mem_buffers_154.rrd

/var/www/html/cacti/rra/db-m2-slave-1_mem_free_191.rrd

/var/www/html/cacti/rra/localhost_mem_buffers_3.rrd

/var/www/html/cacti/rra/db-m2-slave-2_mem_free_164.rrd

/var/www/html/cacti/rra/db-m2-slave-2_mem_buffers_162.rrd

/var/www/html/cacti/rra/db-m2-slave-1_mem_buffers_54.rrd

/var/www/html/cacti/rra/db-m2-slave-1_mem_swap_55.rrd

/var/www/html/cacti/rra/db-master-2_lock_system_memory_114.rrd

/var/www/html/cacti/rra/db-m2-slave-2_mem_cache_163.rrd

/var/www/html/cacti/rra/db-m2-slave-1_mem_cache_190.rrd

/var/www/html/cacti/rra/db-master-2_mem_free_146.rrd

[root@squid-2 local]#

[root@squid-2 local]# rrdtool info /var/www/html/cacti/rra/db-m2-slave-1_mem_free_191.rrd |grep mem_free

filename = "/var/www/html/cacti/rra/db-m2-slave-1_mem_free_191.rrd"

ds[mem_free].type = "GAUGE"

ds[mem_free].minimal_heartbeat = 120

ds[mem_free].min = 0.0000000000e+00

ds[mem_free].max = 1.0000000000e+07

ds[mem_free].last_ds = "34166500"

ds[mem_free].value = NaN

ds[mem_free].unknown_sec = 2

[root@squid-2 local]#

注：ds[mem_free].max = 1.0000000000e+07 数据的最大值设置为10G

查看rrdtool如何进行修改，执行—help查看：

[root@squid-2 local]# rrdtool --help

Compiled Aug 21 2010 10:57:18

Usage: rrdtool [options] command command_options

Valid commands: create, update, updatev, graph, graphv, dump, restore,

last, lastupdate, first, info, fetch, tune,

resize, xport

RRDtool is distributed under the Terms of the GNU General

Public License Version 2. (www.gnu.org/copyleft/gpl.html)

For more information read the RRD manpages

[root@squid-2 local]#

采用tune命令参数进行修改：

[root@squid-2 rra]# rrdtool tune *_mem_free_*.rrd mem_free:100000000

DS[mem_free] typ: GAUGE hbt: 120 min: 0.0000 max: 10000000.0000

[root@squid-2 rra]#

有提示信息，表名tune失败，原来少了个-a参数，重新修改如下：

[root@squid-2 rra]# rrdtool tune *_mem_cache_*.rrd -a mem_cache:3000000000

[root@squid-2 rra]# rrdtool tune *_mem_free_*.rrd -a mem_free:3000000000

[root@squid-2 rra]# rrdtool tune *_mem_buffers_*.rrd -a mem_buffers:3000000000

[root@squid-2 rra]#

这里发现rrdtool执行之后，只有一个host主机的的nan变成数字，其他主机的都没有变，之所以如此是因为rrdtool tune * -a …命令只有一个.rrd文件起作用，其余的需要自己手动再一次次执行rrdtool tune命令。

为了简化操作，特意写了一个ssh脚本如下：

vim /root/rrdtool_increate_mem.sh
cd /var/www/html/cacti/rra
ls *_mem_free_*.rrd -1 >a_mem_free.txt
for i in `cat a_mem_free.txt`
do
	rrdtool tune $i -a mem_free:300000000;
done;

ls *_mem_cache_*.rrd -1 >a_mem_cache.txt
for i in `cat a_mem_cache.txt`
do
	rrdtool tune $i -a mem_cache:300000000;
done;

ls *_mem_buffers_*.rrd -1 >a_mem_buffers.txt
for i in `cat a_mem_buffers.txt`
do
	rrdtool tune $i -a mem_buffers:300000000;
done;

直接sh /root/rrdtool_increate_mem.sh即可。

【补充】

调试cacti的graph，步骤如下：

(1) Console ，再进入Graph Manager ,再进入，选择对于的Host，搜索Memory，选中你要的图，点击链接，比如我这里是Memory Usage，如下图所示：