Merge pull request #75488 from szarkos/szark-20190501

Add information about image update cadence and Azure-tuned kernels

Author: SyntaxC4

articles/virtual-machines/linux/endorsed-distros.md

@@ -14,24 +14,24 @@ ms.workload: infrastructure-services
 ms.tgt_pltfrm: vm-linux
 ms.devlang: na
 ms.topic: article
-ms.date: 11/21/2017
+ms.date: 05/01/2019
 ms.author: szark
 
 ---
-# Linux distributions endorsed on Azure
+# Endorsed Linux distributions on Azure
 Partners provide Linux images in the Azure Marketplace. We are working with various Linux communities to add even more flavors to the Endorsed Distribution list. In the meantime, for distributions that are not available from the Marketplace, you can always bring your own Linux by following the guidelines at [Create and upload a virtual hard disk that contains the Linux operating system](https://docs.microsoft.com/azure/virtual-machines/linux/create-upload-generic).
 
 ## Supported distributions and versions
-The following table lists the Linux distributions and versions that are supported on Azure. Refer to [Support for Linux images in Microsoft Azure](https://support.microsoft.com/help/2941892/support-for-linux-and-open-source-technology-in-azure) for more detailed information about support for Linux and open source technology in Azure.
+The following table lists the Linux distributions and versions that are supported on Azure. Refer to [Support for Linux images in Microsoft Azure](https://support.microsoft.com/help/2941892/support-for-linux-and-open-source-technology-in-azure) for more detailed information about support for Linux and open-source technology in Azure.
 
-The Linux Integration Services (LIS) drivers for Hyper-V and Azure are kernel modules that Microsoft contributes directly to the upstream Linux kernel.  Some LIS drivers are built into the distribution's kernel by default. Older distributions that are based on Red Hat Enterprise (RHEL)/CentOS are available as a separate download at [Linux Integration Services Version 4.2 for Hyper-V and Azure](https://www.microsoft.com/en-us/download/details.aspx?id=55106). See [Linux kernel requirements](create-upload-generic.md#linux-kernel-requirements) for more information about the LIS drivers.
+The Linux Integration Services (LIS) drivers for Hyper-V and Azure are kernel modules that Microsoft contributes directly to the upstream Linux kernel.  Some LIS drivers are built into the distribution's kernel by default. Older distributions that are based on Red Hat Enterprise (RHEL)/CentOS are available as a separate download at [Linux Integration Services Version 4.2 for Hyper-V and Azure](https://www.microsoft.com/download/details.aspx?id=55106). See [Linux kernel requirements](create-upload-generic.md#linux-kernel-requirements) for more information about the LIS drivers.
 
 The Azure Linux Agent is already pre-installed on the Azure Marketplace images and is typically available from the distribution's package repository. Source code can be found on [GitHub](https://github.com/azure/walinuxagent).
 
 
 | Distribution | Version | Drivers | Agent |
 | --- | --- | --- | --- |
-| CentOS |CentOS 6.3+, 7.0+ |CentOS 6.3: [LIS download](https://www.microsoft.com/en-us/download/details.aspx?id=55106)<p>CentOS 6.4+: In kernel |Package: In [repo](http://olcentgbl.trafficmanager.net/openlogic/6/openlogic/x86_64/RPMS/) under "WALinuxAgent" <br/>Source code: [GitHub](https://github.com/Azure/WALinuxAgent) |
+| CentOS |CentOS 6.3+, 7.0+ |CentOS 6.3: [LIS download](https://www.microsoft.com/download/details.aspx?id=55106)<p>CentOS 6.4+: In kernel |Package: In [repo](http://olcentgbl.trafficmanager.net/openlogic/6/openlogic/x86_64/RPMS/) under "WALinuxAgent" <br/>Source code: [GitHub](https://github.com/Azure/WALinuxAgent) |
 | [CoreOS](https://coreos.com/docs/running-coreos/cloud-providers/azure/) |494.4.0+ |In kernel |Source code: [GitHub](https://github.com/coreos/coreos-overlay/tree/master/app-emulation/wa-linux-agent) |
 | Debian |Debian 7.9+, 8.2+ |In kernel |Package: In repo under "waagent" <br/>Source code: [GitHub](https://github.com/Azure/WALinuxAgent) |
 | Oracle Linux |6.4+, 7.0+ |In kernel |Package: In repo under "WALinuxAgent" <br/>Source code: [GitHub](https://go.microsoft.com/fwlink/p/?LinkID=250998) |
@@ -40,7 +40,25 @@ The Azure Linux Agent is already pre-installed on the Azure Marketplace images a
 | openSUSE |openSUSE Leap 42.2+ |In kernel |Package: In [Cloud:Tools](https://build.opensuse.org/project/show/Cloud:Tools) repo under "python-azure-agent" <br/>Source code: [GitHub](https://github.com/Azure/WALinuxAgent) |
 | Ubuntu |Ubuntu 12.04+ **<sup>1</sup>** |In kernel |Package: In repo under "walinuxagent" <br/>Source code: [GitHub](https://github.com/Azure/WALinuxAgent) |
 
-  - **<sup>1</sup>** For Ubuntu 12.04 support on Azure please refer to the [EOL notice](https://azure.microsoft.com/blog/ubuntu-12-04-precise-pangolin-nearing-end-of-life/).
+  - **<sup>1</sup>** Information about extended support for Ubuntu 12.04 and 14.04 can be found here: [Ubuntu Extended Security Maintenance](https://www.ubuntu.com/esm).
+
+
+## Image update cadence
+Azure requires that the publishers of the endorsed Linux distributions regularly update their images in the Azure Marketplace with the latest patches and security fixes, at a quarterly or faster cadence. Updated images in the Azure Marketplace are available automatically to customers as new versions of an image SKU. More information about how to find Linux images: [Find Linux VM images in the Azure Marketplace](https://docs.microsoft.com/azure/virtual-machines/linux/cli-ps-findimage).
+
+### Additional links
+ - [SUSE Public Cloud Image Lifecycle](https://www.suse.com/c/suse-public-cloud-image-life-cycle/)
+
+## Azure-tuned kernels
+
+Azure works closely with various endorsed Linux distributions to optimize the images that they published to the Azure Marketplace. One aspect of this collaboration is the development of "tuned" Linux kernels that are optimized for the Azure platform and delivered as fully supported components of the Linux distribution. The Azure-Tuned kernels incorporate new features and performance improvements, and at a faster (typically quarterly) cadence compared to the default or generic kernels that are available from the distribution.
+
+In most cases you will find these kernels pre-installed on the default images in the Azure Marketplace, and so Azure customers will immediately get the benefit of these optimized kernels. More information about these Azure-Tuned kernels can be found in the following links:
+
+ - CentOS Azure-Tuned Kernel - Available via the CentOS Virtualization SIG - [More Info](https://wiki.centos.org/SpecialInterestGroup/Virtualization)
+ - Debian Cloud Kernel - Available with the Debian 10 and Debian 9 "backports" image on Azure - [More Info](https://wiki.debian.org/Cloud/MicrosoftAzure)
+ - SLES Azure-Tuned Kernel - [More Info](https://www.suse.com/c/a-different-builtin-kernel-for-azure-on-demand-images/)
+ - Ubuntu Azure-Tuned Kernel - [More Info](https://blog.ubuntu.com/2017/09/21/microsoft-and-canonical-increase-velocity-with-azure-tailored-kernel)
 
 
 ## Partners