{"record":{"id":"a3933ac14c2de306","repo":"vllm-project/vllm","slug":"sleep-mode-backend-name-is-not-supported-on-th","errorCode":null,"errorMessage":"Sleep-mode backend '{name}' is not supported on this platform.","messagePattern":"Sleep-mode backend '(.+?)' is not supported on this platform\\.","errorType":"validation","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"vllm/device_allocator/sleep_mode_backend.py","lineNumber":181,"sourceCode":"\n    @classmethod\n    def get_backend_class(cls, name: str) -> type[SleepModeBackend]:\n        \"\"\"Resolve a registered backend class by name.\"\"\"\n        if name not in cls._registry:\n            available = \", \".join(sorted(cls._registry)) or \"<none>\"\n            raise ValueError(\n                f\"Unsupported sleep-mode backend '{name}'. \"\n                f\"Registered backends: {available}.\"\n            )\n        return cls._registry[name]()\n\n    @classmethod\n    def create_backend(cls, model_config: ModelConfig) -> SleepModeBackend:\n        \"\"\"Instantiate the backend selected by ``model_config``.\"\"\"\n        name = model_config.sleep_mode_backend\n        backend_cls = cls.get_backend_class(name)\n        if not backend_cls.is_supported():\n            raise ValueError(\n                f\"Sleep-mode backend '{name}' is not supported on this platform.\"\n            )\n        logger.info(\"Using sleep-mode backend: %s\", name)\n        return backend_cls()\n\n\n# Register built-in backends here. Registration is lazy: only the module for the\n# selected backend is imported. Third-party backends (CUDA checkpoint, CRIU,\n# durable snapshot) register the same way through a vllm.general_plugins entry\n# point, without changes to vLLM core.\nSleepModeBackendFactory.register_backend(\n    \"cumem\",\n    \"vllm.device_allocator.sleep_mode_backend\",\n    \"CuMemBackend\",\n)\n","sourceCodeStart":163,"sourceCodeEnd":197,"githubUrl":"https://github.com/vllm-project/vllm/blob/c794754062d49a8fdb63ab3c5215b488b865030c/vllm/device_allocator/sleep_mode_backend.py#L163-L197","documentation":"Raised by SleepModeBackendFactory.create_backend after resolving the backend class when its is_supported() returns False. Registration is lazy and name-based; the platform check happens at instantiation, so a valid name still fails here if the runtime lacks the required hardware/driver support.","triggerScenarios":"Selecting a sleep-mode backend whose is_supported() is false on this machine, e.g. the cumem backend without CUDA uVM support, or a CRIU backend without the CRIU runtime present.","commonSituations":"Running on a GPU/driver combination that lacks the needed feature; missing system packages (criu, specific driver level); selecting a backend copied from a different deployment environment.","solutions":["Switch to a sleep-mode backend that is supported on this platform (use the registry list from the sibling error if unsure).","Install/upgrade the missing runtime dependency the backend's is_supported() checks (e.g. driver version, criu package).","If none is supported, drop --sleep-mode on this node."],"exampleFix":"# before\n--sleep-mode-backend cumem    # on a node without required CUDA uVM support\n# after\n--sleep-mode-backend <platform-supported backend>  # or omit --sleep-mode","handlingStrategy":"validation","validationCode":"cls = SleepModeBackendFactory.get_backend_class(name)\nif not cls.is_supported():\n    raise SystemExit(f\"backend {name!r} not supported here; pick another or disable sleep mode\")","typeGuard":"def backend_usable(name: str) -> bool:\n    cls = SleepModeBackendFactory.get_backend_class(name)\n    return cls.is_supported()","tryCatchPattern":"try:\n    backend = SleepModeBackendFactory.create_backend(model_config)\nexcept ValueError as e:\n    if \"not supported on this platform\" in str(e):\n        fallback_to_supported_backend_or_disable_sleep_mode()\n    raise","preventionTips":["Probe is_supported() for all candidate backends during node provisioning.","Bake the supported backend choice into the node's deployment config after a one-time capability scan."],"tags":["vllm","sleep-mode","platform","hardware","driver"],"backgroundTag":null,"analyzedSha":"c794754062d49a8fdb63ab3c5215b488b865030c","analyzedAt":"2026-08-14T21:17:39.825Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}