Remove IMDS v1 Fallback from oci-go-sdk

[JoshuaWR]

This issue tracks the removal of fallback to IMDS v1 endpoints and the introduction of retry logic for IMDS v2 in oci-go-sdk

IMDS (Instance Metadata Service) endpoints provide region information and metadata for Instance Principal, Resource Principal, and etc. To ensure the security and functionality of this feature, IMDS v1 fallback will be removed from all SDKs. After this change, if the IMDS v2 endpoint is unavailable, there will be no fallback to IMDS v1. Applications relying on v1 fallback must update accordingly to avoid service disruptions.

Changes Implemented

Remove Fallback to IMDS v1:

• The SDK will no longer attempt to access IMDS v1 if IMDS v2 requests fail.

Retry Mechanism for IMDS v2 in Auth. A retry strategy has been introduced with:

• 8 retry attempts
• Exponential backoff with Jitter between attempts
• details: {link to retry code}

This change will take effect starting from the version 65.80.0

Impact on Users

Users relying on IMDS v1 or using a version older than 65.80.0 must upgrade to the latest SDK version. Failure to do so may result in disruptions if IMDS v2 encounters issues, as the new versions will no longer fall back to v1.

Action Required

• Review the new retry logic to ensure expected behavior.
• Upgrade to the latest SDK version to remove reliance on IMDS v1.
• Test integrations to confirm seamless operation with the new IMDS v2 behavior.