IMDSv2 slow response

[saracen]

#1489 introduced IMDSv2 support. Similar to the issues described in the official AWS SDK (aws/aws-sdk-go#2972), the IAM credential provider potentially introduces a several minute delay.

A workaround appears to be to adjust the EC2 instances hop limit (details regarding this are also discussed in the aws-sdk-go issue).

The official SDK solved this by setting a 1s timeout for the metadata service request. This bug affects many users of GitLab-Runner (https://gitlab.com/gitlab-org/gitlab-runner/-/issues/28656), and whilst I can fix this in Runner by adjusting the client transport, this will affect all requests and might have ramifications beyond fixing just this problem.

Are we okay to add a similar solution to the official SDK? Maybe by coping the transport and setting a timeout of 1s just for the fetchIMDSToken call? If so, and unless anybody else beats me to this, I should be able to work on this tomorrow.

[harshavardhana]

Are we okay to add a similar solution to the official SDK? Maybe by coping the transport and setting a timeout of 1s just for the fetchIMDSToken call? If so, and unless anybody else beats me to this, I should be able to work on this tomorrow.

Sure feel free to send a PR @saracen