Recovering RHEV Virtual Guests in “Unknown” status after losing access to storage

The last thing you want in a clustered virtualization environment is to lose access to your storage. No storage means no virtual server.

A former RHEV client of mine had a scenario where their storage was some how inaccessible to all the hypervisors in the cluster. They power cycled the RHEV hypervisors and even rebooted the RHEV-M management server a few times, but no matter what they did, all the virtual servers were offline, yet the RHEV-M web interface still reported that they were in an “Unknown” state. Not up and online where you could power it off, and not down where you could power it up, but “Unknown” where basically you can’t do anything.

Without a doubt, the first thing you should be doing in this case is phone Red Hat support and let them know what’s going on.  They will always know the best way to proceed.

I’d like to thank ‘eprasad’ on the #rhev channel on FreeNode for the assistance with this issue.

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Converting VMware disk images to use in KVM

From time to time, you may have a need to convert a VMware based virtual disk image into some other format.

If you use KVM as your virtualization technology or perhaps you are migrating from VMware to KVM, you will need to convert your VMware disk images (.vmdk files) into a supported image type that you can use in KVM.


Individual Image files

If you have a single vmdk file, you can convert it with the below command.

qemu-img convert -f vmdk disk-image.vmdk -O raw disk-image.img

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Deploying a replicated NAS solution using Red Hat Storage Server 2.0

Before I begin, I’d like to thank Gavin Spurgeon for his assistance in verifying my work and assisting in my understanding of the technologies used here. Up until recently this technology was a new topic for me. Thanks Gav.

All customers who have any sized infrastructure, be it large or small, will require a storage solution of some form. The solution of choice will always be subject to finding the right solution for the job. This could be a standard file server for small customers, a NAS (Network Attached Storage) or in the case of medium to large sized infrastructures, even a Fibre Channel or iSCSI SAN (Storage Area Network).

This article will focus specifically on NAS type solutions, however will reference in comparison to file servers and SAN solutions in parts.
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Deploying VMware vSphere 5.0

Just over a week ago I sat the VMware Install, Manage and Configure training course as a prerequisite to gaining my VCP accreditation. I have been using VMware products for around 10 years now, so I find a lot of things in the area of virtualization to be common knowledge. I have decided to write this article on vSphere for those of you who are new to the product.

A few weeks ago I wrote a similar article on Red Hat Enterprise Virtualization, which is the current competitor to VMware which uses the underlying KVM virtualization technology.

VMware has been the market leader in virtualization for more years than I can remember. Virtualization is their primary business function and they have their fingers in many pies within the technology industry. As a result they have a huge market share, huge list of vendors supporting their products and an even larger number of customers.

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Deploying Red Hat Enterprise Virtualization

Virtualization, to many people, is a very hot topic when it comes to many people working in Technology. Many people see it as some new fancy thing that has been around for a few years, but it has been around for a LONG time. It is truely astounding how many people still have no idea what virtualization is, let alone having any plans to deploy it in their infrastructure.

VMware have ruled the market in this area for over the past 10-15 years, however they have a serious competitor. Whilst VMware stay put over in the blue corner, not really offering much more than in recent years other than charging their customers through the nose for their solution, over in the red corner, is Red Hat offering a solution that not only significantly outperforms VMware’s products with obscene statistics, but the TCO is also obscenely cheaper than what VMware can offer.

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