Add UCX Plugin Bundling for NIXL install script

[pi314ever]

This adds support for ucx plugin bundling into install_nixl.py, which is needed for gaudi_gdr and other ucx plugins in nixl.

[Copilot]

Pull request overview

This PR adds UCX plugin bundling support to the NIXL installation script, enabling the inclusion of gaudi_gdr and other UCX plugins in the NIXL wheel package. The changes focus on extending the build process to bundle UCX plugins and making the UCX commit configurable.

Key Changes:

• Added a new step (4/4) to bundle UCX plugins into the repaired wheel using a helper script
• Made UCX commit configurable via command-line argument with a default commit hash
• Updated UCX build configuration to enable Gaudi support and examples

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[Copilot]

The sed command modifies a Python helper script by commenting out a line. This is fragile and could break if the helper script's code changes. Consider adding a command-line flag to the helper script to skip NIXL plugins instead of modifying the script with sed, or check if the helper script already supports such a flag.

Suggested change

	# Patch the helper script to skip NIXL plugins (since we only want UCX)
	# This prevents it from failing when it can't find system NIXL plugins
	sed_expr = 's/add_plugins(wheel_path, args.nixl_plugins_dir, "nixl")/# &/'
	run_command(["sed", "-i", sed_expr, helper_script])
	print(f"--> Adding plugins from {ucx_plugins_src}", flush=True)
	bundle_cmd = [
	sys.executable,
	helper_script,
	# Patch the helper script to skip NIXL plugins (since we only want UCX).
	# This prevents it from failing when it can't find system NIXL plugins.
	helper_to_use = helper_script
	try:
	with open(helper_script, "r", encoding="utf-8") as f:
	helper_source = f.read()
	target_call = 'add_plugins(wheel_path, args.nixl_plugins_dir, "nixl")'
	if target_call in helper_source:
	patched_source = helper_source.replace(
	target_call,
	f"# {target_call} # disabled by install_nixl.py: NIXL plugins not bundled",
	)
	patched_helper = os.path.join(
	temp_wheel_dir, "wheel_add_ucx_plugins_patched.py"
	)
	with open(patched_helper, "w", encoding="utf-8") as f:
	f.write(patched_source)
	helper_to_use = patched_helper
	else:
	print(
	"--> Warning: Could not find NIXL plugins call in helper script; "
	"running helper script unmodified.",
	flush=True,
	)
	except OSError as e:
	print(
	f"--> Warning: Failed to prepare patched helper script ({e}); "
	"running helper script unmodified.",
	flush=True,
	)
	print(f"--> Adding plugins from {ucx_plugins_src}", flush=True)
	bundle_cmd = [
	sys.executable,
	helper_to_use,

[Copilot]

The UCX commit hash lacks context explaining why this specific commit was chosen. Consider adding a comment explaining the significance of this commit (e.g., 'UCX commit with Gaudi GDR support' or a reference to the UCX version/tag it corresponds to).

Suggested change

	# Known-good UCX commit tested with the current NIXL version; update only after validation.

[github-actions]

🚧 CI Blocked

The main CI workflow was not started for the following reason:

Your branch is behind the base branch. Please merge or rebase to get the latest changes.

[github-actions]

🚧 CI Blocked

The main CI workflow was not started for the following reason:

Your branch is behind the base branch. Please merge or rebase to get the latest changes.

[github-actions]

🚧 CI Blocked

The main CI workflow was not started for the following reason:

Your branch is behind the base branch. Please merge or rebase to get the latest changes.

[github-actions]

✅ CI Passed

All checks passed successfully against the following vllm commit:
aa125ecf0edb9cd67656553d11d643aeb444ff9e

[pi314ever]

Combined with #711 for complete integration with CI