GitHub has enabled Arm-based Linux and Windows runners for its Actions service, used to test and deploy code. The new runners are priced at 37 percent less than x64 equivalents, and are currently only available for paid accounts.

According to GitHub product manager Larissa Fortuna there will be a new class of runner images developed in cooperation with Arm. A partner image repository shows two new images, one running Ubuntu 22.04 (the latest long term support version) for general use, and the other an Arm Virtual Hardware (AVH) image aimed at edge IoT (Internet of Things) use cases. Both are designated as beta images.

The post adds that only customers on Team and Enterprise cloud plans currently have access to the new runners, though they should be available to open source projects by the end of 2024. In GitHub terminology, the new runners are categorized as “larger runners,” which accounts for the restricted availability.

There are several reasons to use Arm runners. One is cost saving, with around 37 percent lower price for equivalent runners. As an example, the pricing table shows an 8-core AMD64 Linux runner at $0.032 per minute, and an 8-core arm64 Linux runner at $0.02 per minute.

A second reason is sustainability, and Fortuna claims 30 to 40 percent less power consumption for arm64 images.

A reason not to use Arm runners is where there are native code dependencies and only x64 libraries are available, or when building for an x64 target.

The addition of arm64 runners to GitHub actions is another sign of the advance of Arm in the mainstream server market. That said, the Windows images for Arm runners are for Windows 11, not Windows Server. The next version of Windows Server is 2025 – will there be an Arm version? Microsoft watchers have spotted the Canary channel release of Windows Server Insider Preview on the unofficial UUP dump site, which assembles Windows setup images from Microsoft’s update servers, suggesting that an Arm64 version may be in preparation.

Windows 11 on Arm64 appears to be central to Microsoft’s recently announced Copilot+ PCs and native builds are now appearing for popular third-party applications including Chrome, Spotify, Zoom, WhatsApp, Photoshop and more.

AWS introduced its Graviton processor for EC2 (Elastic Compute Cloud) in November 2018 and said last November that ” every one of the top 100 Amazon Elastic Compute Cloud (EC2) customers makes use of Graviton, choosing between more than 150 Graviton-powered instances.”

Arm64 VMs are also available on Google Cloud Platform.

The surprise, perhaps, is that it has taken this long for GitHub to offer hosted Arm64 runners. “I can’t help but feel like I am part of a huge market segment that GitHub lost during the ARM64 runner absence,” said a developer on Hacker News.