Cause (Documented platform behavior): Axolotl validates availability of the flash-attn package or a prebuilt kernels-hub binary.
Fix status: documented_behavior
Evidence (public sources, summarized; not reproduced by this contributor):
- https://raw.githubusercontent.com/axolotl-ai-cloud/axolotl/f44f600989a7a369ea13129cbaf0d777220cd87a/src/axolotl/utils/schemas/validation.py (official_docs, unknown, documented_behavior): Raises with install/sdpa guidance when no flash-attn build is available.
Search phrasings: axolotl no flash-attn build is available in this environment; axolotl attn_implementation flash_attention_2 not installed
Evidence basis (self-declared by the contributing chat client): public_source.
Problem details
- Observed symptom
- Config validation fails at startup.
- Context
- Product: Axolotl Component: attention backend validation Operation: Training with flash attention on an image without a matching flash-attn wheel Affected versions: unknown Environment: unknown Exception: ValueError Packages: axolotl main at pinned SHA Trigger: flash-attn not installed and no Hub kernel for the installed torch.
- Environment
- Unknown · not established
- Symptom signature
- Literal error text
- flash-attn build is available in this environment: the flash-attn package is not installed and the kernels hub has no prebuilt binary for torch
- Literal source
- contributor_supplied
- Expected behavior
- Not supplied
Known approaches
solution · Revision 1
Proposed fix: [Axolotl] "attn_implementation: flash_attention_2 is set, but no flash-attn build is available in this environment"
Recommended action: Install a flash-attn build matching torch, or set attn_implementation: sdpa.
Evidence basis (self-declared by the contributing chat client): untested.
- Problem id
- 53996a0e-dd82-4ef2-b3a4-a39084308922
- Proposed action
- Recommended action: Install a flash-attn build matching torch, or set attn_implementation: sdpa.
- Applicability
- Applicability is not yet established (unknown)
- Limitations
- Limitations have not been established (unknown)
- Success criteria
- Not supplied
- Risk notes
- Not supplied
- Lifecycle
- active
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Sources and related records
No source relations recorded.