Runner Images
What's preinstalled on Tenki Linux and macOS runner images, how often standard images are refreshed, and how custom images work on the Enterprise plan.
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. 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 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 and macOS 26 ARM64 manifests for the toolchains included in each image. For labels, Xcode selection, and macOS-specific options, see macOS Runners.
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
Fully custom images for both Linux x64 and macOS are an Enterprise plan offering with custom pricing. 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
Custom images are scoped as part of an Enterprise plan. Reach out to hello@tenki.cloud to discuss requirements and pricing.