taken the lid off Red Hat Enterprise Linux (RHEL) 6.2, Though it's a modest update, Red Hat has a laundry list of improvements to KVM and the kernel that will make it easier to set resource limits and improve performance for virtualized systems.Red Hat has
Last week I spoke to Tim Burke, VP of Linux engineering for Red Hat to get a look at what's coming in the release. Aside from the usual collection of security patches and bug fixes since 6.1, Burke says that 6.2 is emphasizing performance, scalability and manageability. Naturally, Red Hat is also including support for new hardware in this release as well.
In RHEL 6.2, Burke says that it will be easier to use cgroup resource controls to control CPU consumption, memory consumption, and I/O consumption. This is important for a lot of shops that need to ensure that virtual machines don't go over their limits. Burke says that it's also usable for bare metal applications, and for hosted cloud providers like OpenShift.
OpenShift and RHEL 6.2
It's unclear how much Red Hat's OpenShift effort is driving features in RHEL 6.2, but Burke did say that Red Hat is learning quite a bit from developing OpenShift and is already using 6.2 to host its PaaS. For example, Burke says that OpenShift makes heavy use of Linux Containers and "really stresses" logical volume management (LVM). "It's so dynamic, and we want it to be as rapid as possible to deploy [on OpenShift]."
Linux Containers don't get as much attention as KVM, but they can be used in cases where a full virtual machine may not make sense. With 6.2, the features for managing Containers are available via a GUI or using libvirt. Note that Containers are considered a "technology preview" in 6.2, though. Burke says it's "not generically suited for a full spectrum of workloads," but says it is being used heavily in OpenShift.
He also says that OpenShift "heavily uses a lot of the tool stack" that ships with RHEL, such as Perl, Python and Ruby.
RHEL 6.2 is also a major component of Red Hat Enterprise Virtualization 3.0 which is in beta right now.
Burke says that RHEL 6.2 has made it easier to configure resource policies. If you're using RHEL 6.2 with RHEV 3.0, Burke notes that a lot of the resource policy management is now exposed via GUI tools that ship with RHEV – though those are not available just with RHEL 6.2.
On the device side, RHEL 6.2 has added support for new Infiniband devices, a bunch of new 10GbE network cards, and better utilities for configuring Fibre Channel over Ethernet (FCoE).
It's worth noting, of course, that the cgroup and KVM features are not exclusive to Red Hat. The features are being developed in the upstream Linux kernel, and they're available to any vendor that's using the Linux kernel. Red Hat may be one of the first to market with these features in an enterprise Linux distribution, but the kernel/KVM improvements aren't exclusive.
For a full list of improvements, see Red Hat's What's New Guide (PDF) for 6.2.