The last one here

If you like to follow me, please visit my blog at http://hermannsspace.de/

Accessing OMD unter CentOS and Selinux

If you've got the error like this

OMD: Site Not Started

You need to start this site in order to access the web interface.


in your fresh configured and started OMD site, Selinux can cause the issue. Consider to configure Selinux properly (have a lot of fun!) or disable it in /etc/syssconfig/selinux.

CentOS and Active Directory 2008

This article is intended for those of you, who has read my old post about CentOS and the integration into Microsoft Active Directory. In my old post I referred to Microsoft Active Directory 2003. In cases, when you upgraded to MS AD 2008, you have to update some entries in configuration file /etc/nslcd.conf.

Yum's additional tools

I've learnt new helpful commands recently that belongs to yum tools (thank you MLLR). I'd like to say a few words about the usage of the commands.

hermannmaurer's photostream

hermannmaurer's photostream on Flickr.

My Flickr photostream

In Berlin

Fortigate firewall check package for Check_MK updated

I've updated the package to the version 1.6. This version contains an additional check of IPSec tunnel status of a Fortigate firewall. It works for FGT-300C and FGT-60C units. Other models can work as well, but I could not test.

You can download the new package at the known place from the Check MK Exchange repository.

Find parent path to a mail enabled public folder

In EMC of Exchange 2010 you can use the following command to show the parent path to a mail-enabled public folder:

get-recipient address@domain.com | Get-MailPublicFolder  | Get-PublicFolder

Name                                         Parent Path

----                                         -----------

address@domain.com                           \folder1\folder2

OMD fails to start after CentOS upgrade to 6.4

I faced a problem starting OMD 0.54 after upgrading CentOS to the version 6.4. The start script returns a bunch of error messages:


[root@omd ~]# omd restart mysite
Doing 'restart' on site mysite:
Creating temporary filesystem /omd/sites/mysite/tmp...mount: can't find /omd/sites/                         mysite/tmp in /etc/fstab or /etc/mtab
ERROR
Removing Crontab...
Stopping xinetd...OK
Stopping icinga...Not running. OK
npcd was not running... could not stop
Stopping rrdcached...waiting for termination...OK
Stopping dedicated Apache for site mysite....OK
Starting dedicated Apache for site mysite...OK
Starting rrdcached...OK
Starting npcd...touch: cannot touch `/omd/sites/mysite/tmp/pnp4nagios/run/npcd.pid'                         : No such file or directory
chown: cannot access `/omd/sites/mysite/tmp/pnp4nagios/run/npcd.pid': No such file or directory
An Error occured while reading your config on line 197
Message was: "Could not open pidfile '/omd/sites/mysite/tmp/pnp4nagios/run/npcd.pid                         ': No such file or directory"
OK
/omd/sites/mysite/etc/rc.d/80-icinga: line 54: /omd/sites/mysite/tmp/nagios/nagios.cfg                         : No such file or directory
Icinga configuration file /omd/sites/mysite/tmp/nagios/nagios.cfg not found. Terminating...
Starting xinetd...OK
Initializing Crontab...OK

I found a couple of reports about the same problem. The root cause seems to be a bug (or a feature?) in the package util-linux-ng-2.17.2-12.9.el6.x86_64 that prevents non root users to mount partitions from /etc/fstab, whose path name conatains a symlink (symbolic link). In case of OMD /omd is a symlink pointing to /opt/omd.

A workaround that helped me to solve the problem was adding /opt to the appropriate path in /etc/fstab:

tmpfs                   /opt/omd/sites/nysite/tmp  tmpfs   noauto,user,mode=755,uid=mysite,gid=mysite 0 0

Check_MK check for Fortigate firewalls

I've got a Fortigate 60C and wanted to monitor it in Check_MK. I could find a plugin written by Justin McMillen, but it didn't work in the version 1.1.2 of Check_MK. Also they seemed to use SNMP OIDs, which my Fortigate 60C didn't have. So I've updated his checks and created a new version of the plugin. The checks use SNMP to get CPU and RAM usage as ell as the session count. You can download the package from Check_MK Exchange site.

Version 1.3.2 of Ex2010_MBDB_Info released

Again I've released a new version of the check. I've changed only the Windows plugin. Now the spaces in a mailbox database name are replaced by underscores. I hope this change would help all of you, who experienced problems with the plugin.

To update it's enough to download the new check package, install it in your check_mk instance by a command like this:

cmk -vP install Ex2010_MBDB_Info-1.3.2.mkp

and substitute the cmd file on your Exchange server by the Ex2010_MBDB_Info.ps1 file from the new package.

You can find the new version of the package at the known place at the check_mk plugin exchange site.

Version 1.3.1 of Ex2010_MBDB_Info released

I've released a new version of the check. I've changed the Windows plugin. It is now a pure Powershell script, not a command script anymore. It should run smoothly to avoid problems, which some of you had in the past running the plugin.
To update it's enough to download the new check package, install it in your check_mk instance by a command like this:

cmk -vP install Ex2010_MBDB_Info-1.3.1.mkp

and substitute the cmd file on your Exchange server by the Ex2010_MBDB_Info.ps1 file from the new package.

You can find the new version of the package at the known place at the check_mk plugin exchange site.

Upgrade Microsoft Hyper-V Linux IC from 3.3 to 3.4

Recently I had to upgrade the integration components on a lot of CentOS virtual systems running on a Hyper-V failover cluster. During the upgrade procedure I faced a couple of things, which I'd like you to be aware of. The version on the guest VM is CentOS 6.3, the Hyper-V failover cluster is running under Windows Server 2008 R2 SP1 and consists of 6 nodes.

Below is the output of LVM related commands before starting the upgrade of Linux IC:

Find differences in Public Folder replicas

This is a small piece of code to run it in EMS and to help you finding differences in item number in a public folder structure. The powershell script shows the number of elements in each sub folder for the both of Exchange 2010 servers, which public folder replicas are located on. Below is an example output of the script.


[PS] C:\>C:\scripts\get-pffolderdiffs.ps1

Path                                       ItemCount_SRV1 ItemCount_SRV2
----                                       -------------- --------------
\PF1\VPC                                                 0             0
\PF1\VPC\Exec                                         1739          1739
\PF1\VPC\Exec\2007                                   20406         20406
\PF1\VPC\Exec\2008                                   21952         21952
\PF1\VPC\Exec\2009                                   27804         27804
\PF1\VPC\Exec\2010                                   16888         16888
\PF1\VPC\Exec\2011                                   39021          1869
\PF1\VPC\Exec\2012                                   15734         15734

Please note that the script is provided AS IS without any guarantee:


$PF='\PF1'
$SR1='SRV1'
$SR2='SRV2'


Get-PublicFolder -Server $SR1 -ResultSize unlimited -Identity $PF -Recurse `
  | Sort-Object -Property @{expression={$_.ParentPath + '\' + $_.Name}} |
ft @{label="Path"; expression={ $_.ParentPath + "\" + $_.Name }},
   @{label="ItemCount_$SR1"; expression={ `
     (get-PublicFolderStatistics -Server $SR1 ($_.ParentPath + '\' + $_.Name) `
  | Select-Object -ExpandProperty ItemCount) }}, `
   @{label="ItemCount_$SR2"; expression={ `
     (get-PublicFolderStatistics -Server $SR2 ($_.ParentPath + '\' + $_.Name) `
  | Select-Object -ExpandProperty ItemCount) }} -auto

Check_MK check to show some data about Ex2010 mailbox databases

A few days ago I finished to test a new check for check_mk and published it as package at Check_MK Exchange. I named the check "Ex2010_MBDB_Info". In this article I'd like to share a couple of details about the check and its functionality.

The purpose of the check is to get the size of mailbox databases and the count of the mailboxes in each of them. The check package consists of the check itself, the plugin for check_mk agent, the perf-o-meter helper file and the pnp-template.

Extending a LVM partition in a Hyper-V guest VM running CentOS

Imagine a scenario like the following: you have a Hyper-V host and a CentOS 6.3 guest. The CentOS guest has Microsoft Integration Services for Linux 3.3 installed and running. A data file system on the guest is running out of the free space:

[root@myhost ~]# df -h /data/svn/

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/data-svn   99G   93G  964M  99% /data/svn

Although the partition is a part of LVM, but your entire disk is almost full. In the article I'd like to show how you can get rid of this without getting your services offline.

Lock and unlock an ActiveSync device

Assume, a mobile phone or tablet device with a buggy implementation of the ActiveSync protocol causes a lot of traffic or a heavy load in your Exchange 2010 infrastructure (see this article of mine for an example). You surely could disable the ActiveSync feature for the Mailbox user to disable the access for the user completely. A better way is however to disable only the device, which causes the troubles.

Exchange management shell offers cmdlets to manage ActiveSync devices:

Exchange 2010 transaction logfiles grow very fast

A few days ago I had a problem with transaction log files on a Exchange 2010 SP2 RU1 mail server. They grown and grown and grown... I saw above 160,000 (one hundred sixty thousand !!!) files belonging to a single mailbox database. The mailbox database itself was ca. 30 GByte in size. It was then no surprise that the appropriate volume exceeded it capacity after only a couple of hours.

I wouldn't even have noticed the issue but the appropriate backup job that should flush transaction log files among other things failed and didn't run. Because of the failed backup job the transaction log files were not flashed and were not removed but grown.

Transport-Rule in Exchange 2010 to prefix the Subject

Assume, you'd like to prepend the subject of an e-mail with a prefix, if the e-mail has been sent from the certain computer and if it has a certain sender name. In this case you can create a new transport rule with Powershell.

For example, the subject should be prepended by the phrase '[Alert]', if the From address contains 'my_sender@company.com' AND if the computer's name, which the email is sent from, is 'my_computer.company.com'. The powershell command below configures this:

New-TransportRule
-Name 'My_transport_rule' -Comments 'My comment'
-HeaderContainsMessageHeader 'Received' -HeaderContainsWords 'my_computer.company.com '
-FromAddressContainsWords 'my_sender@company.com' -PrependSubject "[Alert] "

After the command has been executed the rule is active. It acts in the whole Exchange organization and is not restricted to a single server.

Please note that the argument for the parameter -HeaderContainsWords must contain the name, which the email program on the sender computer actually uses. If the new rule doesn't work as expected, look into the internet headers of a test e-mail and note the computer name, which is in the line Received.

Check_MK plugin to get firmware and service tag of a DELL Powerconnect switch

check_mk is a great monitoring application! I've been trying it for a couple of days first and I am convinced that check_mk has a big future due to its nice conception, super built-in capabilities and the ability to create own check plugins with less effort.

I also tried to create a new check plugin for DELL Powerconnect switches, because the check plugins for such switches provided by check_mk distribution cannot show the firmware version and the service tag of the switch. I copied a provided check plugin (to be more accurate: snmp_info)and modified it a little bit. I'd like to share my result below, please enjoy it!