Cloud storage file mounts for gs://

[Michaelvll]

Our task is still not available to mount gs:// storage. Can we check the GCLOUD_PROJECT and GOOGLE_APPLICATION_CREDENTIALS in the environment, then set the environment on the remote instance and send the credential to it?

[michaelzhiluo]

This is addressed in #102.

[michaelzhiluo]

It might take a while for Sky Init to be merged, so I will push a hotfix for this, which will be later overwritten by Sky Init.

[concretevitamin]

@Michaelvll The current sky credentials design is that the user must have certain credential files locally (hinted by sky init). It's not enough to just have environment vars.

The reason for not doing env vars is because authentication in the clouds has much more cases than just files + env vars. For AWS, their metadata service means an empty VM has access to a user's AWS credentials. For GCP, it's also not simple: ref1, ref2. This is a topic for more investigation.

tl;dr Give master a try now to see if the tasks can access gs://private-bucket? If not, running the hint in sky init should work.