Tag Archives: CentOS

Adding a new HDD to the existing VG

Sometimes you need to extend the existing volume group to be able to add free space to the logical volumes in there.

Look at this situation:

[root@localhost ~]# vgs data
 VG #PV #LV #SN Attr VSize VFree
 data 1 1 0 wz--n- 39.99g 0

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Collect pnp4nagios data in Check_MK distributed environment

Introduction

I hope you enjoy the great monitoring software Check_MK. If you have a big environment with lots of hosts and services distributed over dozen of sites (company locations) , you might have already configured your Check_MK to use the distributed monitoring in WATO. I assume that you have got a master and some slaves. The master in terms of Check_MK is the host, which you are using to configure your whole Check_MK installation and to look at all hosts and services, whilst slaves are those hosts that receive the configuration from the master and which the master gets the monitoring results from.  Distributed monitoring is an extremely nice and powerful feature of Check_MK that allows you to keep your configuration at one place and that takes care on distributing the changes on the configuration to the slaves. Also it’s very easy to connect a new slave to the master site.

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Reverse proxy timeouts with Check_MK

In some distributed environments and with a lot of configured users and connection to Microsoft active directory configured in Check_MK times to distribute the changes from the master to all slave sites grow up strongly. Check_MK distributed monitoring uses Apache web server acting as reverse proxy. Sometimes one of Apache web server’s instances doesn’t return data within a pre-defined time range. In such cases you can get the error like this while trying to replicate your slave with the master site:

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Notes on usage of Check_MK Multisite with LDAPS

I had to configure OMD/Check_MK version 1.2.4p3 to use LDAPS to connect to Windows domain controller. The operating system on the host running OMD/Check_MK is CentOS 6.5 x64.

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Extend a Logical Volume to 100% of Volume Group

To extend a logical volume (LV) named ´logs` to the whole space of the volume group (VG) named ´data` execute the following command:

# lvextend -l 100%VG /dev/data/logs