fix(models): fix default model_puller image for NIMCache

[anubhutivyas]

Issue:

• Creating a deployment on k8s backend fails during NIMCache init with below error because the NIMCache pod runs the platform nmp-api image, which does not contain download-to-cache.

Error: failed to start container "nim-cache-ctr": OCI runtime create failed:
exec: "download-to-cache": executable file not found in $PATH

• compile_nimcache builds a NIMCache CR where the HF source modelPuller is set from the models service's huggingface_model_puller whose value is set to nmp-api image by default

Change:
Following how we have a separate field in DockerBackendConfig for docker backend, create a new field huggingface_model_puller in K8sNimOperatorConfig and set the default as nds-v2-huggingface-cli:25.10, which ships download-to-cache.

Summary by CodeRabbit

• New Features
  • Added a new configuration option for the Hugging Face model-puller image used by NIMCache, with a pinned default image.
• Documentation
  • Updated the configuration reference to reflect the new default and clarify the cache-population entrypoint behavior.
• Bug Fixes
  • Ensured NIMCache downloads for Files-service–backed deployments consistently use the configured puller image.
• Tests
  • Updated and added unit tests to validate the default puller image behavior and related NIMCache generation.

[github-actions]

Suite	Lines Covered	Line Rate	Branch Rate
Unit Tests	26387/34035	77.5%	61.8%
Integration Tests	15176/32660	46.5%	18.7%

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📥 Commits

Reviewing files that changed from the base of the PR and between 6421ccc and 6e5d51b.

📒 Files selected for processing (2)

• services/core/models/src/nmp/core/models/controllers/backends/k8s_nim_operator/backend.py
• services/core/models/src/nmp/core/models/controllers/backends/k8s_nim_operator/reconcilers/nim_operator.py

💤 Files with no reviewable changes (1)

• services/core/models/src/nmp/core/models/controllers/backends/k8s_nim_operator/backend.py

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📝 Walkthrough

Walkthrough

The NIM operator now configures its Hugging Face model puller through K8sNimOperatorConfig, using a pinned CLI image by default. NIMCache compilation and reconciliation consume this setting, with tests covering custom and default puller behavior.

Changes

NIM operator model puller

Layer / File(s)	Summary
Puller configuration contract services/core/models/.../k8s_nim_operator/config.py, docs/set-up/config-reference.mdx	Adds the huggingface_model_puller setting with the nds-v2-huggingface-cli:25.10 default and documents its download-to-cache entrypoint.
NIMCache compilation and reconciliation services/core/models/.../k8s_nim_operator/nimservice_compiler.py, services/core/models/.../k8s_nim_operator/reconcilers/nim_operator.py, services/core/models/.../k8s_nim_operator/backend.py	Removes the compiler and reconciler puller arguments, reads the image from backend configuration, and updates reconciliation wiring.
Puller behavior tests services/core/models/tests/unit/controllers/test_nimservice_compiler.py, services/core/models/tests/unit/controllers/test_k8s_nim_operator_backend.py	Updates test setup for the configuration-based image and verifies the pinned default excludes nmp-api.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: fixing the default model puller image for NIMCache.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[albcui]

Since you added the model puller to the K8sNimOperatorConfig, this is redundant information. We should just rely on the backend_config.huggingface_model_puller.

[anubhutivyas]

This was actually left as is intentionally because I didn't want to touch the tool-call-plugin's container image, but thinking through this I feel it won't break anything as we were using the nds image earlier too. Removed _huggingface_model_puller from contructor and now using backend_config.huggingface_model_puller everywhere.

[anubhutivyas]

Closing it because we have removed the k8s-nim-operator in this PR - #705