Environment variables

KERNELS_CACHE

The directory to use as the local kernel cache. If not set, the cache of the huggingface_hub package is used.

UNSTABLE_KERNELS_ALL_LATEST

Set to 1 to ignore requested kernel versions, revisions, and lockfile pins when loading kernels. This is an unstable development mode: kernel API changes may break your code. Do not enable it in production.

UNSTABLE_KERNELS_ALL_LATEST=1 python your_script.py

This applies to get_kernel, has_kernel, get_locked_kernel, load_kernel, and the Hub dependencies of get_local_kernel, including transitive dependencies. Layer and function mappings, including locked repositories, follow the same policy. The highest numbered version branch (for example, v10 rather than v2) is selected. Repositories without numbered versions raise an error; this mode never falls back to main. If the selected version has no compatible build, loading fails instead of falling back to an older version. A warning reports the requested version or revision and the selected ref and commit.

Even with this mode enabled, get_kernel and has_kernel require an explicit version or revision. Passing both remains an error. Local paths and LOCAL_KERNELS overrides take precedence where supported. Lockfile-based loaders still require a lockfile containing the requested kernel, but ignore its pins and resolve dependencies from the selected version’s metadata. Lockfiles are not modified. Installation and lockfile generation commands are unaffected.

In offline mode, only cached numbered version refs are considered. If none are available, loading raises an error even if main is cached. load_kernel always uses the cache, even when online. The selected version’s build must already be cached; this may differ from the latest version on the Hub.

ON, YES, and TRUE also enable this mode (case-insensitive). Unsetting the variable, or any other value including 0, restores normal pinning. The variable is read on each loader call.

DISABLE_KERNEL_MAPPING

Disables kernel mappings for layers.

HF_HUB_DISABLE_TELEMETRY

Disable telemetry.