# Runner Images (https://tenki.cloud/docs/runners/runner-images)

> For the complete documentation index, see [llms.txt](https://tenki.cloud/llms.txt)

What's preinstalled on Tenki Linux and macOS runner images, how often standard images are refreshed, and how to request custom images.

This page describes what's on a Tenki runner image out of the box, how we build them, and how custom images work.

## Linux x64 default image

Tenki Linux x64 runners use the **official GitHub Actions runner images** maintained at [`actions/runner-images`](https://github.com/actions/runner-images). The default image is **Ubuntu 24.04**.

Practical consequence: anything that runs on GitHub-hosted `ubuntu-latest` runs on Tenki Linux runners with no changes.
The toolchains (Node, Python, Ruby, Java, Go, Rust, Docker, gcloud, AWS CLI, fastlane, Android SDK + NDK, etc.) mirror GitHub's published software list.
The [`actions/runner-images` software list](https://github.com/actions/runner-images#available-images) is the authoritative manifest.

## macOS standard images

Tenki macOS Runners are available with **macOS 15 Sequoia** and **macOS 26 Tahoe**.
The macOS 15 image defaults to Xcode 16, while the macOS 26 image defaults to Xcode 26.
Both images mirror the official GitHub-hosted ARM64 software lists.
See the [macOS 15 ARM64](https://github.com/actions/runner-images/blob/main/images/macos/macos-15-arm64-Readme.md) and [macOS 26 ARM64](https://github.com/actions/runner-images/blob/main/images/macos/macos-26-arm64-Readme.md) manifests for the toolchains included in each image.
For labels, Xcode selection, and macOS-specific options, see [macOS Runners](https://tenki.cloud/docs/runners/macos-runners.md).

## Update cadence

Tenki refreshes standard Linux and macOS images once per month to bring the installed software back into parity with GitHub's published images.
There can be a short delay between a GitHub image update and the next Tenki monthly refresh.
Exact tool and patch versions can therefore change when a refreshed image is deployed.

## Custom images

We support fully custom images for both Linux x64 and macOS. Typical use cases:

* Internal SDKs, proprietary tooling, or licensed dependencies that can't live in a public registry
* A specific Xcode / simulator matrix that needs to be locked in
* Pre-warmed caches for very large monorepos

Reach out to [hello@tenki.cloud](mailto:hello@tenki.cloud).