Recently, as you could see in previous posts, oVirt got to my attention. oVirt is the upstream project of Red Hat Enterprise Visualization or RHEV. While oVirt it isn’t providing everything that competitor VMWare ESXi does, it comes close and is a very good alternative for smaller or home setups. For a long time, oVirt wasn’t supported on Enterprise Linux 7 (like RHEL 7 or CentOS 7) but since a short time it is. Here you can find how to install oVirt and get started.
When working in an environment where you have both a VMWare hypervisor and an oVirt or RHEV hypservisor or you want to migrate away from VMWare ESX to oVirt or RHEV, you will need a way to move or copy your current virtual machines from one to another. Unfortunately this can’t be done without downtime but at least it can be done. In this post I’ll try to explain how to successfully move a VM running on ESX or vCenter to an oVirt or Red Hat Enterprise Virtualization host.
Recently, I started to work or play, it’s a matter of definition, a little more with oVirt. oVirt is less known than VMWare but it’s the upstream project for Red Hat’s Enterprise Virtualization (RHEV) and based on libvirt. In an earlier post, I explained how to create VM’s on VMWare vSphere environments using Python and the VMWare API. In this post, I’ll explain how to acomplish the same using the oVirt API. It turned out to be easier than I expected.
Somehow, I expected to have little to no work when I wanted to monitor an oVirt host over SNMP. One would expect this since oVirt is the upstream project for Red Hat’s Enterprise Virtualization (RHEV) which seems to be quite strong in the market. While it isn’t that hard to get information about using SNMP for oVirt or libvirt the outcome can be disappointing. There is some documentation about it but here you can find a more hands-on explanation.
When your VM’s file systems are running out of space and you want to provide more space to your VM and you can’t afford any downtime, there are basically two options. Either you delete some files on the file system or you expand your current file system. Expanding your current file system can be accomplished by growing an existing virtual disk or adding a new virtual disk. Besides cleaning up, both other solutions work fine and I’ll try to explain how to get both of them active without rebooting the system or any downtime.
The VMWare API is very extensive and allows you to do almost all operations that are possible with VMWare using API calls. In order to be able to easily create and deploy new virtual machines, it can be a good idea to standardize and create VM’s using a (Python) script that calls the API. In this post, I will give some examples on how to easily create a new VM using Pysphere and the VMWare API.
Cloning a virtual machine or user as it is called in z/VM terms from within another guest/user running Linux can be used in a lot of different scenario’s. Especially when the people managing the z/VM platform and virtual machines are less experienced with z/VM, it could be good to let them create a clone without the need to access a 3270 terminal. This scenario can also be used to let users do some self service and provide them with new instances without intervention.
Earlier, I explained how to setup CentOS or RHEL as a KVM virtualization host. You can find that explanation here. It also contains some basic terminology about virtualization which is also applicable for Xen. When talking about KVM, somehow, I immediately associate it with the Red Hat family just as when you talk about Xen, I associate it to Debian derivatives. So for this post, I’ll use Debian to install a host that will run Xen-VM’s by using paravirtualization.
OpenStack is something that gets more and more in the picture and even if you’re only a little interested in the latest technologies, you must have heard from OpenStack here or there. But what is it exactly and more important, how does it work practically. The best way to figure that out is just to get going with it and try to install it and play around. Here you can find a brief explanation and a tutorial or waltrough to deploy a small OpenStack environment on top of CentOS 7 or RHEL 7.
When thinking about virtualization, everybody immediately thinks about VMWare. And it must be said, the product they offer is very decent but also comes with a “decent” price. As an alternative, it’s worth looking into KVM for your virtualization. As with the VMWare product range, KVM offers full virtualization and it can compete with VMWare regarding stability and performance.