ConVirt: the New Tool in Your Virtual Toolbox
Note that in order to migrate running guests between hosts, both hosts must have access to the same shared storage. You may run into other limitations when migrating guests, such as both hosts must have the same processor type and/or must be on the same hypervisor platform (like KVM or Xen), so plan accordingly. I was unable to determine whether this was a technical limitation or an unlocked feature in the enterprise version of ConVirt. Either way, there are some native tools in the hypervisors that can convert foreign disk/VM types for importation into their native platform. After you have met all the prerequisites, migrating is as simple as right-clicking the guest and selecting your destination server. You can monitor your migration task in the bottom pane of the console.
One last feature I want to mention is ConVirt's management of shared storage, because I think it is useful (Figures 8 and 9). With the designer's tree-based approach to organizing virtual resources, you set shared storage at the Data Center-level and then attach it to Server Pools, which gives you the ability to mix and match your storage among the pools. Be aware that for all servers in the pool to use the storage, they must connect to the storage using the same logical path (like migration). I found this feature incredibly useful as it really simplifies assignment of any networked storage resources you have in your environment (SAN, iSCSI or NFS). You also can set certain provisioning settings at the pool level that override those in a template. This means you can provision the same template with multiple storage options. This would be very handy if you have Server Pools in different sites or different departments, each that should use their own storage resources.
Figure 8. Shared Storage Details
Figure 9. Server Pools That Can Use This Storage
In this article, I've touched on many of the nicer features in ConVirt, but now let me talk about some things that are missing. Before doing so, you should recognize that I am comparing apples and oranges when I talk about ConVirt and vendor-produced management tools. Even comparing the Enterprise version of ConVirt is not wholly accurate, as ConVirt is meant to manage a heterogeneous virtual environment whereas Microsoft and VMware are tuned to their own homogeneous platforms.
That being said, I still had a few gripes with ConVirt. The first is that it requires root access to managed servers to communicate with the CMS, which I am sure most admins won't be crazy about. Snapshot support also is noticeably missing from the open-source version. There is an option available for the VMs called Hibernate, but that takes a snapshot only of the running memory not the underlying disk. The lack of snapshots bothered me only for half-a-second when I realized it is available in the Enterprise version. The last item missing from ConVirt is administrative roles. You do have the ability to create users and groups in the console, but as far as I can tell, the only thing that gets you is auditing of the tasks that take place on the CMS server. It felt like this was added into the product in its most basic form, but never fully developed.
In the end, these are minor complaints as ConVirt provides far more utility than the few features it lacks. The software really gives you a lot of flexibility, especially with KVM, and you can't beat the price point. I'm sure those features unlocked in the Enterprise version (snapshots, high availability and spanned virtual networks) are worth the money and bring it more in line with the vendor-produced management offerings. I know how much VMware costs, and I am sure ConVirt comes in under that. I will say that you really need to know your chops when managing different hypervisors at the same time. I am one of those admins who works with vSphere daily, and I have become accustomed to a homogeneous environment, so I really had to get under the hood of both KVM and Xen to make things go smoothly. That being said, once it in place, I believe it is easier to administer by non-Linux IT pros or admins who need to perform day-to-day tasks in their virtual environment than virt-manager or command-line tools. Add in the ability to manage a multiplatform hypervisor environment, and the value of ConVirt is apparent.
Convirture's Main Site: http://www.convirture.com
Installation Guide/Wiki: http://www.convirture.com/wiki/index.php?title=Convirt2_Installation