Linux Red Hat

How to install Munin-node on RHEL6

Munin-node is not available per default on RHEL6 servers. But luckily, somebody has made a mirror which contains many nice applications, including the munin packages we want.

rpm -Uvh

yum install perl-XML-SAX

yum install munin-node

And voila! 🙂

perl-XML-SAX has to be installed first due to dependency issues.

Edited 7.march 2013, updated URL`s


Linux Red Hat

RHEV: Cannot export VM. VM with the same identifier already exists

When trying to export a virtual machine via the RHEV (Red Hat Enterprise Virtualization), either via the API or via the RHEVM admin console, you might encounter the error message “Cannot export VM. VM with the same identifier already exists”.

This is thrown when you are trying to export a VM to a location which already have the VM there, perhaps an older copy of the VM.

If you are doing this via the RHEVM admin console, simply select “force override”, to overwrite any existing VM there.

Now, if this is the API, then you must specify this via the action command, via an exclusive command:

<action><storage_domain><name>*STORAGE DOMAIN TO EXPORT TO*</name></storage_domain><exclusive>true</exclusive><discard_snapshots>false</discard_snapshots></action>

The documentation says that you should use overwrite, but this is wrong/a bug, and is confirmed by Red Hat.

There is also another reason which can trigger this, and which is in my eyes, a bug. If the VM already exist on the export domain, but with another name, then you will get this error no matter what. The only work around i know about so far is to make sure that the names are correct both places. I have contacted Red Hat to get this checked up.

Red Hat

Getting snmpwalk on Red Hat 5 (rhel5)

Needed snmpwalk on one of my Red Hat 5 boxes today, yum search snmpwalk gave no clues, but after some digging i found it in the package net-snmp-utils. 🙂

yum install net-snmp-utils

Red Hat

Installing NRPE on Red hat 6

Red Hat 6 does not natively support NRPE/Nagios with the default package manager. Luckily, DAG can save the day again, just as with Red Hat 5 🙂

Simply add the mirror spesified in the link above to your server and you get the ability to add the NRPE or other Nagios packages without too much hazzle.

In my case with a 64bit system, the way to get NRPE installed was as simple as this:

rpm -Uhv

yum install nagios-nrpe

Red Hat

Yum on Red Hat 5 hangs when using proxy

I had a machine that started hanging when running yum update on it. And the only way to actually stop yum then was to kill the process from another shell, pretty strange.

I noticed that it was trying to look up and old proxy server which was not in use anymore, the machine itself got online without issues on other services but then i realised that the file “/etc/sysconfig/rhn/up2date” had a entry for yum proxy settings.

It is also worth checking all files in your “/etc/yum” folder and make sure that none of your repo files have dedicated proxy settings defined since that will override anything from up2date.

When commenting out that proxy setting, yum started behaving again.