CNAME我使用 munin 作为监控服务，并且对它很满意。它位于本地主机上server.domain.com。尝试server.domain.com从远程机器访问时，会显示 munin 主页，其中包含图表和一些很酷的东西。一段时间后，某些插件的图表会停止工作，但我没有注意到了。几天后，我意识到我的 munin 出了问题，我在想，即使我没有对它进行任何更改，munin 怎么可能停止正常工作。我意识到，唯一的配置，可以影响 munin 性能的因素是 apache 配置的改变（基本上我创建了一堆 VirtualHosts 来管理我的子域）。
我认为，munin 认为它位于不同的机器上localhost（例如因为 mysql 说Access denied for user 'debian-sys-maint'@'localhost'，我不知道用户是谁，它在哪里知道这样的用户（在 munin 的配置文件中找不到它）并且它之前工作正常，我没有对 munin 配置进行任何更改根本）。
因此，总结一下，munin 运行良好。在更改 apache2 VirtualHost 配置（可能移动 munin，但仍在单台机器上）后，mysql、apache、NFS 的图表停止工作。其他图表（如磁盘、网络、进程）仍正常工作。
我可以提供有关系统或来自 apache、munin、mysql 或任何其他系统的日志的任何其他信息，但我不知道要提供哪些日志，因为我不知道问题的主要原因是什么。
编辑
我正在提供 munin 日志。
munin-update.log:
2015/09/11 16:20:02 [INFO]: Starting munin-update
2015/09/11 16:20:02 [INFO] starting work in 9389 for server.domain.com/127.0.0.1:4949.
2015/09/11 16:20:04 [WARNING] Service nfs_client on server.domain.com/127.0.0.1:4949 returned no data for label link
/* same message for label: lookup,setattr,readlink,create,remove,write,read,symlink,rename,rmdir,commit,mknod,fsstat,getattr,fsinfo,pathconf,readdirplus,mkdir,access,readdir */
2015/09/11 16:20:04 [WARNING] Service nfsd on server.domain.com/127.0.0.1:4949 returned no data for label access
/* same message for label: mkdir,readdir,fsinfo,pathconf,readdirplus,fsstat,getattr,commit,mknod,symlink,rename,rmdir,remove,write,read,create,link,lookup,setattr,readlink */
2015/09/11 16:20:08 [WARNING] Service mysql_innodb on server.domain.com/127.0.0.1:4949 returned no data for label free
/* same message for label: open_downgrade,readlink,server_caps,setclientid_confirm,setclientid,getacl,lock,write,rename,open_noattr,statfs,close,lookup_root,getattr,delegreturn,fsinfo,access,lookup,link,setattr,locku,create,renew,lockt,read,remove,symlink,setacl,commit,open_confirm,pathconf,openreaddir */
2015/09/11 16:20:10 [WARNING] Service mysql_queries on server.domain.com/127.0.0.1:4949 returned no data for label select
/* same message for label: update,insert,delete,replace,cache_hits */
2015/09/11 16:20:10 [INFO]: Munin-update finished for node domain.com;server.domain.com (8.45 sec)
2015/09/11 16:20:10 [INFO] Reaping Munin::Master::UpdateWorker<domain.com;server.domain.com>. Exit value/signal: 0/0
2015/09/11 16:20:10 [INFO]: Munin-update finished (8.69 sec)
munin-node.log:
2015/09/11-16:20:02 CONNECT TCP Peer: "[::ffff:127.0.0.1]:53822" Local: "[::ffff:127.0.0.1]:4949"
2015/09/11-16:20:02 [9390] Error output from mysql_:
2015/09/11-16:20:02 [9390] Unknown graph at /etc/munin/plugins/mysql_ line 831.
2015/09/11-16:20:02 [9390] Service 'mysql_' exited with status 255/0.
2015/09/11-16:20:02 [9390] Error output from mysql_:
2015/09/11-16:20:02 [9390] Unknown graph at /etc/munin/plugins/mysql_ line 874.
2015/09/11-16:20:02 [9390] Service 'mysql_' exited with status 255/0.
2015/09/11-16:20:05 [9390] Error output from mysql_isam_space_:
2015/09/11-16:20:05 [9390] /usr/bin/mysqlshow: Access denied for user 'debian-sys-maint'@'localhost' (using password: YES)
2015/09/11-16:20:05 [9390] Service 'mysql_isam_space_' exited with status 1/0.
2015/09/11-16:20:05 [9390] Error output from mysql_isam_space_:
2015/09/11-16:20:05 [9390] /usr/bin/mysqlshow: Access denied for user 'debian-sys-maint'@'localhost' (using password: YES)
2015/09/11-16:20:05 [9390] Service 'mysql_isam_space_' exited with status 1/0.
2015/09/11-16:20:08 [9390] Error output from mysql_innodb:
2015/09/11-16:20:08 [9390] ERROR 1045 (28000): Access denied for user 'debian-sys-maint'@'localhost' (using password: YES)
2015/09/11-16:20:08 [9390] ERROR 1045 (28000): Access denied for user 'debian-sys-maint'@'localhost' (using password: YES)
2015/09/11-16:20:10 [9390] Error output from mysql_queries:
2015/09/11-16:20:10 [9390] mysqladmin: connect to server at 'localhost' failed
2015/09/11-16:20:10 [9390] error: 'Access denied for user 'debian-sys-maint'@'localhost' (using password: YES)'