[Provisioner] Check ports for cloud not specified cases

[cblmemo]

As mentioned in #3125, previously SkyPilot would not print correct ports not supported message if the resources has no cloud specified, and all enabled cloud has no ports support. This PR fixes the problem.

Tested (run the relevant ones):

• Code formatting: bash format.sh
• Any manual or new tests for this PR (please specify below)
  • Start a new docker image; only setup runpod credentials; run sky check; then sky serve up the YAML described in Deployment Issue with serving Model on RunPod  #3125

(base) root@26a1fb705d3d:/sky_repo/skypilot# SKYPILOT_DEBUG=0 sky serve up ../a.yaml 
Service from YAML spec: ../a.yaml
ValueError: Cannot specify ports without enabling a cloud that supports open ports.

• All smoke tests: pytest tests/test_smoke.py
• Relevant individual smoke tests: pytest tests/test_smoke.py::test_fill_in_the_name
• Backward compatibility tests: bash tests/backward_comaptibility_tests.sh

[concretevitamin]

For discussion: How about adding OPEN_PORTS to requested features in execution.py#_execute()? This seems to make failover (from a cloud that doesn't support ports to one that does) work?

[concretevitamin]

I don't remember if task.resources being a set means any_of is being used. (We should add a comment to Task.resources.) In that case, we can have any_of { ..requesting ports.., ..not requesting ports.. }, and the logic here will effectively disallow the second resource.

Is the above right? Wdyt is the best way to handle this?

[cblmemo]

Yeah you are right... And it seems like we don't need the handle here since we will add resources-specific cloud required features and remove any related cloud for each resources in current master:

skypilot/sky/clouds/cloud.py

Lines 341 to 353 in 2f0432b

	resources_required_features = resources.get_required_cloud_features()
	if num_nodes > 1:
	resources_required_features.add(
	CloudImplementationFeatures.MULTI_NODE)
	try:
	self.check_features_are_supported(resources,
	resources_required_features)
	except exceptions.NotSupportedError:
	# TODO(zhwu): The resources are now silently filtered out. We
	# should have some logging telling the user why the resources
	# are not considered.
	return ([], [])

[cblmemo]

Actually here we should only add task-level features like stop and multi-node

[concretevitamin]

The logic in execution.py should've caught this case?

[cblmemo]

This is for better UX. The current master is already disabling the resources with ports if only cloud that does not support ports are enabled; but it will print some message like in #3125:

I 02-08 22:42:32 optimizer.py:1219] No resource satisfying <Cloud>(ports=['8080']) on RunPod.
sky.exceptions.ResourcesUnavailableError: Catalog does not contain any instances satisfying the request:
Task(run='conda activate vllm\...')
  resources: <Cloud>(ports=['8080']).