zabbix_agentd.log里面有出现host [] not found错误的解决
tail -f /usr/local/zabbix/logs/zabbix_agentd.log
12965:20150601:164955.060 Starting Zabbix Agent [123.56.46.172]. Zabbix 2.0.6 (revision 35158).
12969:20150601:164955.061 agent #3 started [listener]
12970:20150601:164955.061 agent #4 started [active checks]
12968:20150601:164955.061 agent #2 started [listener]
12967:20150601:164955.062 agent #1 started [listener]
12966:20150601:164955.062 agent #0 started [collector]
12970:20150601:164955.190 No active checks on server: host [123.56.46.172] not found
12970:20150601:165155.327 No active checks on server: host [123.56.46.172] not found
出现该错误的原因是一般是zabbix_agentd.conf里面的Hostname和前端zabbix web里面的配置不一样所造成的，即在zabbix web页面Monitoring->Configuration->Hosts 页面的Name和zabbix_agentd.conf里面的Hostname要一样,
一致就行，不需写完整的ip
重启agent服务，错误消失
service zabbix_server start
error while loading shared libraries:libmysqlclient.so.18: cannot open shared object file: No such file or directory
ln-s /opt/mysql/mysql-5.5.39-linux2.6-x86_64/lib/libmysqlclient.so.18 /usr/lib64/libmysqlclient.so.18
