Automatically set project-id and zone

[dadoonet]

The project id can be retrieved from the running instance by calling http://metadata.google.internal/computeMetadata/v1/project/project-id.

Same for the default zone: http://metadata.google.internal/computeMetadata/v1/project/attributes/google-compute-default-zone

No need then to force them in elasticsearch.yml.

[DaveCTurner]

@dadoonet could you clarify what needs doing here? The first point sounds like that a value for cloud.gce.project_id could be obtained from the GCE metadata service (presumably still allowing a manual override), right? I don't understand the second point: I see that there's a cloud.gce.zone setting, but this seems to want to be a list of all zones to search for nodes, not just the default zone?

[dadoonet]

The first point sounds like that a value for cloud.gce.project_id could be obtained from the GCE metadata service (presumably still allowing a manual override), right?

Yes.

I see that there's a cloud.gce.zone setting, but this seems to want to be a list of all zones to search for nodes, not just the default zone?

Indeed but if not set we can just fill that list with the current zone only which is I believe what users are doing most of the time I guess: deploying in one single zone.

[DaveCTurner]

Ah right. I was thinking more about AWS availability zones of which it's best to use more than 1, but if that's a common way to use GCE then that makes sense.

[vladimirdolzhenko]

com.google.cloud.ServiceOptions#getDefaultProjectId tries to resolve project based on

• system property GOOGLE_CLOUD_PROJECT (or legacy system property GCLOUD_PROJECT)
• environment variable GOOGLE_CLOUD_PROJECT or GCLOUD_PROJECT
• from http://metadata.google.internal/computeMetadata/v1/project/project-id

ES assumes system properties as unsafe while environment variables could be predefined (e.g. for ECS Task IAM profile credentials in repository-s3 plugin) on the environment (could it be different from value returned from http://metadata.google.internal/computeMetadata/v1/project/project-id? )

Are we going to use only last method ?