About GitHub-hosted runners

Overview of GitHub-hosted runners

Runners are the machines that execute jobs in a GitHub Actions workflow. For example, a runner can clone your repository locally, install testing software, and then run commands that evaluate your code.

GitHub provides runners that you can use to run your jobs, or you can host your own runners. Each GitHub-hosted runner is a new virtual machine (VM) hosted by GitHub with the runner application and other tools preinstalled, and is available with Ubuntu Linux, Windows, or macOS operating systems. When you use a GitHub-hosted runner, machine maintenance and upgrades are taken care of for you.

You can choose one of the standard GitHub-hosted runner options or, if you are on the GitHub Team or GitHub Enterprise Cloud plan, you can provision a runner with more cores, or a runner that's powered by a GPU processor. These machines are referred to as "larger runner." For more information, see About larger runners.

Using GitHub-hosted runners requires network access with at least 70 kilobits per second upload and download speeds.

Runner Images

GitHub maintains our own set of VM images for our standard hosted runners. This includes the images for macOS, x64 linux and Windows images. The list of images and their included tools are managed in the actions/runner-images repository. Our arm64 images are partner images, and those are managed in the actions/partner-runner-images repository.

Preinstalled software for GitHub-owned images

The software tools included in our GitHub-owned images are updated weekly. The update process takes several days, and the list of preinstalled software on the main branch is updated after the whole deployment ends.

Workflow logs include a link to the preinstalled tools on the exact runner. To find this information in the workflow log, expand the Set up job section. Under that section, expand the Runner Image section. The link following Included Software will describe the preinstalled tools on the runner that ran the workflow.

For more information, see Viewing workflow run history.

GitHub-hosted runners include the operating system's default built-in tools, in addition to the packages listed in the above references. For example, Ubuntu and macOS runners include grep, find, and which, among other default tools.

You can also view a software bill of materials (SBOM) for each build of the Windows and Ubuntu runner images. For more information, see Security hardening for GitHub Actions.

We recommend using actions to interact with the software installed on runners. This approach has several benefits:

• Usually, actions provide more flexible functionality like version selection, ability to pass arguments, and parameters
• It ensures the tool versions used in your workflow will remain the same regardless of software updates

If there is a tool that you'd like to request, please open an issue at actions/runner-images. This repository also contains announcements about all major software updates on runners.

Cloud hosts used by GitHub-hosted runners

GitHub hosts Linux and Windows runners on virtual machines in Microsoft Azure with the GitHub Actions runner application installed. The GitHub-hosted runner application is a fork of the Azure Pipelines Agent. Inbound ICMP packets are blocked for all Azure virtual machines, so ping or traceroute commands might not work. GitHub hosts macOS runners in Azure data centers.

Workflow continuity

If GitHub Actions services are temporarily unavailable, then a workflow run is discarded if it has not been queued within 30 minutes of being triggered. For example, if a workflow is triggered and the GitHub Actions services are unavailable for 31 minutes or longer, then the workflow run will not be processed.

In addition, if the workflow run has been successfully queued, but has not been processed by a GitHub-hosted runner within 45 minutes, then the queued workflow run is discarded.

The etc/hosts file

GitHub-hosted runners are provisioned with an etc/hosts file that blocks network access to various cryptocurrency mining pools and malicious sites. Hosts such as MiningMadness.com and cpu-pool.com are rerouted to localhost so that they do not present a significant security risk.