Azure Tailored Linux Kernel in Ubuntu

by Michal Smereczynski

Canonical (the company behind Ubuntu Linux distribution) with the team at Microsoft Azure announced in September last year, that Ubuntu Cloud Images for Ubuntu 16.04 LTS on Azure have been enabled with a new Azure tailored Ubuntu kernel by default.

You may not know that (at this point) around 40% of all Azure VMs are running Linux, so Linux kernel is right now also a Microsoft case - if you like it or not.

The kernel itself is provided by the linux-azure kernel package. The most notable highlights for this kernel include:

  • Infiniband and RDMAcapability for Azure HPC to deliver optimized performance of compute intensive workloads on Azure A8, A9, H-series, and NC24r.
  • Full support for Accelerated Networking in Azure. * Direct access to the PCI device provides gains in overall network performance offering the highest throughput and lowest latency for guests in Azure. * Transparent SR-IOV eliminates configuration steps for bonding network devices. SR-IOV for Linux in Azure is in preview but will become generally available later this year.
  • NAPI and Receive Segment Coalescing for 10% greater throughput on guests not using SR-IOV.
  • 18% reduction in kernel size.
  • Hyper-V socket capability — a socket-based host/guest communication method that does not require a network.
  • The very latest Hyper-V device drivers and feature support available.

The ongoing collaboration between Canonical and Microsoft will also continue to produce upgrades to newer kernel versions providing access to the latest kernel features, bug fixes, and security updates.

Any Ubuntu 16.04 LTS image brought up from the Azure portal after 2018 September 21st is running on this Azure tailored Ubuntu kernel.