With Ubuntu 12.04.2, the kernel team introduced the idea of the "hardware enablement kernel" (HWE), originally intended to support new hardware for bare metal server and desktop. In fact, the documentation indicates that HWE images are not suitable for Virtual or Cloud Computing environments. The thought was that cloud and virtual environments provide stable hardware and that the newer kernel features would not be needed.
Time has proven this assumption painfully wrong. Take for example the need for drivers in virtual environments. Several of the Cloud providers that we have engaged with have requested the use of the HWE kernel by default. On GCE, the HWE kernels provide support for their NVME disks or multiqueue NIC support. Azure has benefited from having an updated HyperV driver stack resulting in better performance. When we engaged with VMware Air, the 12.04 kernel lacked the necessary drivers.
Perhaps more germane to our Cloud users is that containers are using kernel features. 12.04 users need to use the HWE kernel in order to make use of Docker. The new Ubuntu Fan project will be enabled for 14.04 via the HWE-V kernel for Ubuntu 14.04.3. If you use Ubuntu as your container host, you will likely consider using an HWE kernel.
And with that there has been a steady chorus of people requesting that we provide HWE image builds for AWS. The problem has never been the base builds; building the base bits is fairly easy. The hard part is that by adding base builds, each daily and release build goes form 96 images for AWS to 288 (needless to say that is quite a problem). Over the last few weeks -- largely in my spare time -- I've been working out what it would take to deliver HWE images for AWS.
I am happy to announce that as of today, we are now building HWE-U (3.16) and HWE-V (3.19) Ubuntu 14.04 images for AWS. To be clear, we are not making any behavioral changes to the standard Ubuntu 14.04 images. Unless users opt into using an HWE image on AWS they will continue to get the 3.13 kernel. However, for those who want newer kernels, they now have the choice.
For the time being, only amd64 and i386 builds are being published.. Over the next few weeks, we expect the HWE images to reach full feature parity including release promotions, and indexing. And I fully expect that the HWE-V version of 14.04 will include our recent Fan project once the SRU's complete.
Check them out at http://cloud-images.ubuntu.com/trusty/current/hwe-u and http://cloud-images.ubuntu.com/trusty/current/hwe-v .
As always, feedback is always welcome.