EC2Metadata Available() hangs for 20s when not on EC2

[derekwaynecarr]

In the Kubernetes project, we use the following operation to detect if the cluster is running in an EC2 instance:

https://github.com/aws/aws-sdk-go/blob/master/aws/ec2metadata/api.go#L37

If the cluster is not running in an EC2 instance (for example, I am on bare-metal), this operation blocks and hangs for ~20s because it is unable to resolve the hostname of the metadata server. Since it can't resolve the hostname of the metadata server, it doesn't get an HTTP error since the connection can't even be established and the operation is retried until it has reached its max retry.

It would be good if the operation could either a) not retry, or b) fail quicker when dns name cannot be found.

For history:
kubernetes/kubernetes#22668

[xibz]

Hello @derekwaynecarr, thank you for reaching out to us. You can disable retries by setting MaxRetries, in the config, to 0. Going to close this issue. If you have any more questions, please let us know.

sess := session.New(&aws.Config{
    Region:      aws.String("us-west-2"),
    MaxRetries: aws.Int(0),
})

In addition, this would apply to all requests. You can add this also to the client itself.

svc := ec2metadata.New(sess, &aws.Config {
    MaxRetries: aws.Int(0),
})

[derekwaynecarr]

@xibz thanks for the prompt assistance.