Endorsed Linux distributions on Azure

Applies to: ✔️ Linux VMs ✔️ Flexible scale sets ✔️ Uniform scale sets

In this article, we'll cover the following:

• Types of Images
• Partners
• Image Update Cadence
• Azure-tuned Kernels

There are several different sources of Linux Virtual Machine (VM) images for Azure. Each source provides a different expectation for quality, utility, and support. This document summarizes each source (marketplace images, platform images, custom images, and community gallery images) and gives you more details about platform images, which are images provided in partnership between Microsoft and several mainstream Linux publishers such as Red Hat, Canonical, and SUSE.

Microsoft’s Linux distribution partners provide a multitude of Linux images in the Azure Marketplace. For distributions that aren't available from the Marketplace, you can always provide a custom built Linux image by following the guidelines found in Create and upload a virtual hard disk that contains the Linux operating system. For older versions, see Linux Kernel Requirements.

The Azure Linux Agent is already preinstalled on Azure Marketplace images and is typically available from the distribution package repository. Source code can be found on GitHub.

For more information on support by distribution, see Support for Linux images in Azure.

Types of Images

Azure Linux images can be grouped into three categories:

Marketplace Images

Images published and maintained by either Microsoft or partners. There are a large variety of images from multiple publishers for various use cases (security hardened, full database / application stack, etc.), and can be available free, pay-as-you-go, or BYOL (bring your own license/subscription).

Platform Images are a type of Marketplace images for which Microsoft has partnered with several mainstream publishers (see table below about Partners) to create a set of “platform images” that undergo additional testing and receive predictable updates (see section below on Image Update Cadence). These platform images can be used for building your own custom images and solution stacks. These images are published by the endorsed Linux distribution partners such as Canonical (Ubuntu), and Credativ (Debian).

Microsoft provides commercially reasonable customer support for these images. Additionally, Canonical, and SUSE offer integrated vendor support capabilities for their platform images.

Custom Images

These images are created and maintained by the customer, often based on platform images. These images can also be created from scratch and uploaded to Azure - learn how to create custom images. Customers can host these images in Azure Compute Gallery and they can share these images with others in their organization.

Microsoft provides commercially reasonable customer support for custom images.

Community Gallery Images

These images are created and provided by open source projects, communities, and teams. These images are provided using licensing terms set out by the publisher, often under an open source license. They don't appear as traditional marketplace listings, however, they do appear in the portal and via command line tools. More information on community galleries can be found here: Azure Compute Gallery.

Microsoft provides commercially reasonable support for Community Gallery images.

Platform Image Partners

Image Update Cadence

Azure requires that the publishers of the endorsed Linux distributions regularly update their platform images in Azure Marketplace with the latest patches and security fixes, at a quarterly or faster cadence. Updated images in the Marketplace are available automatically to customers as new versions of an image SKU. More information about how to find Linux images: Find Azure Marketplace image information using the Azure CLI.

Azure-tuned Kernels

Azure works closely with various endorsed Linux distributions to optimize the images that they published to 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'll find these kernels preinstalled on the default images in Azure Marketplace so 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
• Debian Cloud Kernel - Available with the Debian 10 and Debian 9 "backports" image on Azure
• SLES Azure-Tuned Kernel
• Ubuntu Azure-Tuned Kernel