Red Hat beta revs KVM hypervisor to 3.0

Like invasion from space: First we land, then we expand

Commercial Linux distributor Red Hat is kicking out the first beta of its Enterprise Virtualization 3.0 hypervisors for servers and desktops. This brings the free-standing hypervisor up to par with the KVM hypervisor that was embedded in the company's Enterprise Linux 6.1 distro for servers , which came out in May.

KVM is an open source alternative to the Xen hypervisor for x64-based machines, which Red Hat took control of when it bought Qumranet in September 2008 for $107m. Qumranet took the QEMU hardware emulator and paired it with a Linux kernel module to virtualize x86 and x64 machines (with the intent originally being to create virtual desktops) and paired it up with a .NET-based management console that ran on a Windows server called Solid ICE. Since acquiring Qumranet, Red Hat's customers had to use a Windows-based machine to manage their free-standing RHEV hypervisors, somewhat embarrassingly.

With RHEV 3.0, Red Hat has finally ported the .NET console to Java and moved the database behind it from SQL Server to PostgreSQL. You can still use Microsoft's Active Directory for authentication of users and access to resources on the network, but Red Hat is also allowing customers to go all-red and use its own Enterprise IPA (which is not a hoppy beer, but rather an identity manager based on LDAP and Kerberos). The whole shebang runs on Red Hat Linux, of course. The old Windows-based Enterprise Virtualization Manager console will not be able to manage RHEV 3.0, Navin Thadani, senior director of the virtualization business at Red Hat, tells El Reg.

By moving RHEV 3.0 to the underlying RHEL 6.1 Linux, the free-standing KVM hypervisor gets a number of scalability improvements. The underlying physical host machine that KVM can span can have as many as 128 cores (256 threads of the machine are based on Intel's Xeon processors and it has HyperThreading turned on) and up to 2TB of physical main memory. The guest virtual machines riding on top of KVM can scale up to 64 virtual cores or threads and up to 2TB of virtual memory. The prior RHEV 2.2 hypervisor was based on RHEL 5.5 and could only span 96 cores and 1TB of physical memory, and only delivered 16 virtual CPUs and 256GB of virtual memory to each VM guest. This is a significant expansion in capacity for guest VMs, and means just about any workload you can think of will now fit inside of a virtual machine.

The free-standing RHEV 3.0 version of KVM includes a new Java-based power user portal, which allows developers and administrators to use a GUI to provision and manage hypervisors and VMs. The prior portal that was part of the Solid ICE stack was only useful for deploying and managing virtualized PCs. If you wanted a self-service portal for RHEV, you had to make one yourself or get by with scripts.

RHEV 3.0 includes a lot of other tweaks that made it into the KVM hypervisor embedded in RHEL 6.1, including transparent huge pages, asynchronous I/O, block alignment of storage, and the moving of the networking stack from the user space down into the Linux kernel.

Red Hat has also OEMed a version of Jaspersoft's open-source report-writing tools hooked into Enterprise Virtualization Manager to dice and slice the data concerning hypervisors and VMs under its control, and help administrators manage their virtual machines.

And finally, RHEV 3 will allow customers to deploy the hypervisor on a server with direct attached storage instead of a Fibre Channel SAN or iSCSI array. All of the features other than live migration will work on the local storage attached to the server, but moving a VM from one server to another using RHEV still requires shared storage. This will no doubt change in the future, since SMBs don't want to buy shared storage and everyone knows it.

Revving up the attack on VMware

Red Hat does not talk about revenues or shipments of its RHEL and RHEV licenses or its installed base, so it is not clear how well or poorly RHEV is doing relative to RHEL or other hypervisors. But what Thadani can say is that the price hikes that VMware made with the launch of its vSphere 5.0 stack in July – and which it subsequently tweaked downward two weeks ago – only make RHEV look like a better alternative than it might have seemed a year ago.

"The one thing that is clear is that customers are looking for an alternative to VMware because they do not want to be locked in. Before, they didn't really feel like they had a choice, but now they do," he said.

When IT managers looked around their data centers during the Great Recession, it was clear that their Windows-based machines were the least utilized and consolidated, and with VMware focusing on the Windows platform, it was a natural choice for virtualizing Windows workloads despite its high cost, says Thadani. The Linux enthusiasts inside the data center like open-source products, and particularly for something as sensitive and integral as a server hypervisor, and so KVM and Xen tend to be the favorites.

"We are in a classic land-and-expand strategy," explains Thadani. "We land with RHEL and expand to RHEV."

Companies decide to standardize their Linuxes on RHEL, then they virtualize their workloads using either the integrated KVM or RHEV. Then, they look at the cost of vSphere from VMware and decide to try a few Windows workloads on RHEV. Thadani says that prior to VMware's vSphere 5.0 launch and its memory tax, RHEV cost about one-seventh as much per host to virtualize x64 machines with the same number of VMs. But in the wake of the virtual memory tax, even after VMware's rejiggering, RHEV now costs one-fifteenth to one-twentieth of vSphere 5.0 to virtualize a big, fat server.

In some cases, companies are moving from physical Unix boxes to virtual Linux servers in one jump, which is also driving up RHEV shipments and sales, says Thadani. ®

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