Canonical builds a custom Ubuntu kernel for Microsoft Azure. It means that any Ubuntu 16.04 LTS image brought up from the Azure portal after September 2 will be running on this Azure tailored Ubuntu kernel.
Features of latest custom tailored kernel are:
- 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.
Command to verify which kernel is used:
$ uname -r
Command to revert back to the standard kernel:
$ sudo apt install linux-virtual linux-cloud-tools-virtual
$ sudo apt purge linux*azure
$ sudo reboot