Azure Linux Operating System and Management

Azure offers a range of Linux operating systems, including Ubuntu, CentOS, and SUSE.

You can choose from various Azure Linux distributions, including Canonical, Red Hat, and SUSE.

Azure provides a wide range of Linux virtual machines, from small to large instances, to suit different workloads and budgets.

These virtual machines can be easily scaled up or down as needed, making it simple to adjust to changing workload demands.

With Azure Linux, you can also use the Azure CLI to manage your virtual machines, making it easy to automate tasks and integrate with other Azure services.

Getting Started with Azure Linux is a straightforward process. Microsoft offers documentation and tutorials on its website to help you get started.

To begin, check out the tutorial for creating a virtual machine. This will give you a solid understanding of how to deploy a Linux virtual machine using an image from the Azure gallery.

You can choose from a variety of Linux distros, including Ubuntu and SUSE. These distros are available in the Azure gallery, making it easy to get started with Linux on Azure.

Azure also offers a range of automation tools, such as Chef and Puppet. These tools can help you manage and deploy your Linux virtual machines.

Before you start, make sure to check out the Introduction to Linux on Azure page. This page provides an overview of some aspects of using Linux virtual machines in the Azure cloud.

With Azure, you can build apps with popular languages like Python, PHP, Java, and Node.js. You can also run Linux containers with Docker integration, making it easy to deploy and manage your applications.

Azure provides a variety of Linux images for use in Azure Marketplace, including platform images from partners like Canonical (Ubuntu), Red Hat (RHEL), and Credativ (Debian). These platform images undergo additional testing and receive predictable updates.

You can also create your own custom images based on platform images or from scratch and upload them to Azure Compute Gallery. Microsoft provides commercially reasonable customer support for these custom images.

If you've deployed a PAYG image and want to convert it to BYOS, you can use the Azure CLI to apply the RHEL_BYOS or SLES_BYOS license type to the machine. After conversion, you'll need to register the machine with Red Hat or SUSE for system updates and usage compliance.

Here are some key points to keep in mind when working with Azure Linux images:

Azure Marketplace Images are a great resource for finding a variety of images from multiple publishers for various use cases.

You can find images that are free, pay-as-you-go for BYOL (bring your own license/subscription), or security hardened, full database/application stack, and more.

Microsoft has partnered with several mainstream publishers to create a set of "platform images" that undergo additional testing and receive predictable updates.

These platform images are published by endorsed Linux distribution partners such as Canonical (Ubuntu), Red Hat (RHEL), and Credativ (Debian).

Microsoft provides commercially reasonable customer support for these images, and some partners like Red Hat, Canonical, and SUSE offer integrated vendor support capabilities.

To convert a Pay As You Go (PAYG) image to Bring Your Own Subscription (BYOS) using the Azure CLI, you'll need to apply the specific license type for your chosen operating system.

For RHEL images, this involves setting the license type to RHEL_BYOS.

To convert a SLES image, you'll apply the SLES_BYOS license type.

After converting to BYOS, you must register the machine with the respective vendor (Red Hat or SUSE) for system updates and usage compliance.

If you need to revert back to PAYG, you can do so by setting the license type to "None".

Here's a summary of the steps for each operating system:

By following these steps, you can successfully convert your PAYG image to BYOS and manage your licensing model on Azure.

Azure allows customers to host custom images in Azure Compute Gallery, which can be shared with others in their organization. These custom images can be created from scratch and uploaded to Azure.

Microsoft provides commercially reasonable customer support for custom images. This means customers can get help from Microsoft if they need it.

Customers can also use images created by endorsed partners, with around 1,000 images being added to Azure every month. Many of these distributions have multiple images, such as Suse's regular and high-performance computing images.

Docker lets you package an application with all of its dependencies into a standardized unit so it will run the same, regardless of environment.

The container revolution is a trend for platform as a service and compute in general, according to Azure CTO Mark Russinovich.

You can deploy a full Docker host on a virtual machine in minutes, which is a huge time-saver.

Docker is one of the most popular virtualization approaches that uses Linux containers rather than virtual machines.

Creating an Ubuntu server virtual machine in Microsoft Azure and installing a Docker Engine via a VM Extension can be done using images from the Azure Marketplace or the Azure command-line interface.

Custom Images are a great way to manage your image needs, and they can be created and maintained by the customer. Customers can often base these images on platform images, or create them from scratch and upload them to Azure.

These custom images can be hosted in Azure Compute Gallery, making it easy to share them with others in your organization. You can even learn how to create custom images if you're not sure where to start.

Microsoft provides commercially reasonable customer support for custom images, giving you peace of mind that your images are in good hands.

Azure requires that the publishers of endorsed Linux distributions regularly update their platform images in Azure Marketplace with the latest patches and security fixes, at a quarterly or faster cadence.

This ensures customers have access to the most up-to-date images, with updated images in the Marketplace available automatically as new versions of an image SKU.

Azure gets about 1,000 images a month from these endorsed partners, with many distributions having multiple images, such as Suse's regular image and high-performance computing image.

This large influx of images requires careful management to ensure they meet Azure's standards, which is a challenge due to the varying release cycles of each distribution.

Azure wants to standardize safe patching routines into the Azure Guest Patching Service (AzGPS), which will simplify the image update process for customers.

You can run whatever Linux you want in Azure, and even get best-effort support, but it's worth noting that there are many edge cases, including outdated and unsupported distributions.

Azure works closely with various endorsed Linux distributions to optimize the images that they publish to Azure Marketplace.

These optimized kernels are known as Azure-Tuned kernels, and they incorporate new features and performance improvements at a faster cadence than default kernels.

In most cases, you'll find these kernels preinstalled on default images in Azure Marketplace, so customers can immediately benefit from them.

The Azure-Tuned kernels are available for various Linux distributions, including CentOS, Debian, SLES, and Ubuntu.

Here are some specific examples:

At Hyperscale, Microsoft's Azure platform has a surprising history. It started out as a .Net platform-as-a-service in 2008, but customers kept asking for a Microsoft-hosted LAMP Stack.

Today, hundreds of Azure and Azure-based services run on Linux, including AKS, OpenAI, and HDInsight. They're all powered by different flavors of Linux.

Microsoft maintains its own kernel, Azure Linux, and even released its own version of Linux in 2023. But it's just a small portion of the many Linux distributions running on Azure.

About 20,000 third-party Software as a Service (SaaS) packages in the Azure marketplace rely on some Linux distribution. That's a lot of Linux!

Microsoft keeps a set of endorsed Linux distributions, including Red Hat Enterprise Linux, Debian, and Suse. Each has a dedicated user base and Microsoft works with them to ensure their distributions run well on Azure.

To keep packages updated, Microsoft uses the Azure Mirror Infrastructure. This ensures that users get the latest package updates quickly and easily.

The Azure Linux Agent is a crucial component for provisioning a Linux virtual machine in Azure. It's released under the Apache 2.0 license and can be easily installed and updated from the Linux Agent GitHub repo.

The agent requires Python v2.6+ and the python-pyasn1 module, which most distributions provide as a separate package. It's also worth noting that the agent might not be compatible with NetworkManager in some cases.

To avoid provisioning failures, make sure the udf and vfat modules are enabled. Disabling the udf module will cause a failure, while disabling the vfat module will cause both provisioning and boot failures.

Cloud-init version 21.2 or later can provision VMs without requiring UDF under certain conditions. These conditions include creating the VM using SSH public keys and not passwords, and not providing any custom data.

Here's a quick rundown of the requirements for the Azure Linux Agent:

Azure Linux allows you to use Azure Hybrid Benefit (AHB) on certain virtual machines.

Azure dedicated host instances and SQL hybrid benefits aren't eligible for AHB if you already use AHB with Linux virtual machines.

You can enable AHB on new VMs by using the same image and process for both PAYG and BYOS virtual machines. This also enables future licensing mode changes.

To enable AHB when creating a virtual machine, go to the Azure portal, create a virtual machine, and select the checkbox to confirm your subscription is eligible in the Licensing section.

You can use the az vm extension and az vm update commands to update new virtual machines after they've been created.

The correct license types for RHEL are RHEL_BASE, RHEL_EUS, RHEL_SAPAPPS, RHEL_SAPHA, RHEL_BASESAPAPPS, and RHEL_BASESAPHA. For SLES, the correct license types are SLES_STANDARD, SLES_SAP, and SLES_HPC.

You can also enable AHB on existing virtual machines by going to the Azure portal, opening the virtual machine page, and selecting Yes to enable the AHB conversion.

Note that the complete az vm extension depends on the particular distribution you are using.

You can convert a Pay As You Go (PAYG) image to BYOS using the Azure CLI. This process involves applying the RHEL_BYOS or SLES_BYOS license type to the machine using the `az vm update` command.

To convert a RHEL PAYG image to BYOS, use the command `az vm update -g myResourceGroup -n myVmName --license-type RHEL_BYOS`. Once the conversion is complete, register the machine with Red Hat for system updates and usage compliance.

Converting a SLES PAYG image to BYOS is similar, using the command `az vm update -g myResourceGroup -n myVmName --license-type SLES_BYOS`. After conversion, register the machine on your own with SUSE for software updates and usage compliance.

To check the current licensing model of an AHB enabled VM, use the `az vm get-instance-view` command. Look for the AHBForSLES or AHBForRHEL extension to determine if Azure Hybrid Benefit has been enabled.

Here are the corresponding license types for PAYG and BYOS models:

To check if the license type of the VM has been modified, use the `az vm get-instance-view` command. If the license type is not empty, the previous command returns the current licensing model.