Introduction

The Authorization Token has expired issue is a common challenge encountered by users of the AWS Command Line Interface (CLI) on macOS Sierra and other operating systems. This problem typically arises when the temporary security credentials used to access AWS resources have expired. This article provides a comprehensive guide to understanding, diagnosing, and resolving this issue.

Understanding AWS CLI Tokens

When using the AWS CLI, particularly with roles that assume different permissions, AWS uses temporary security credentials. These credentials consist of:

• An Access Key ID
• A Secret Access Key
• A Session Token

These credentials are typically created using AWS Identity and Access Management (IAM) roles and have a limited lifespan. Upon expiration, attempts to execute AWS CLI commands result in the Authorization Token has expired error.

Common Causes

1. Token Expiry: The most straightforward cause is the expiration of temporary credentials. Typically, these tokens last for up to one hour (default) but can be shorter or longer depending on the AWS configurations.
2. Incorrect Time Settings: AWS CLI relies on the system clock of your Mac. If your clock is out of sync by a few minutes, the tokens might appear as expired.
3. Misconfigured AWS CLI Profile: Incorrect or missing configuration in your AWS CLI profile might lead to incorrect or premature expiration of tokens.
4. Role Assumptions: If using multiple roles, confusion or misconfiguration might prevent refreshing the session token correctly.

Diagnosing the Problem

Before jumping into solutions, it’s important to identify the root cause of the issue. Here are some diagnostic steps:

• Check System Time: Ensure that your system time and time zone settings are correct.
• Review Token Expiry Time: Use the aws sts get-session-token command to check current token attributes:

  aws sts get-session-token --duration-seconds 3600

Verify the Expiration field against the current system time.

• Inspect AWS CLI Configuration: Ensure your ~/.aws/config and ~/.aws/credentials files are correct:

  cat ~/.aws/credentials
  cat ~/.aws/config

Fixing the Issue

1. Re-synchronize System Time: Ensure the macOS Sierra system clock is accurate. You can synchronize it with Apple’s NTP server:

   sudo sntp -sS time.apple.com

Alternatively, enable automatic time syncing through System Preferences > Date & Time.

1. Renew Temporary Credentials: To get new credentials, rerun the command or script that generated the existing ones or assume the role again:

   aws sts assume-role --role-arn <RoleArn> --role-session-name <SessionName>

1. Use AWS CLI Environment Variables: Export the refreshed credentials as environment variables:

   export AWS_ACCESS_KEY_ID=<New_Access_Key>
   export AWS_SECRET_ACCESS_KEY=<New_Secret_Key>
   export AWS_SESSION_TOKEN=<New_Session_Token>

1. Automate Credential Refreshing: Consider using AWS Session Manager or a tool like aws-vault to manage and auto-refresh credentials.

Preventive Measures

• Automate Time Sync: Ensure that the Set date and time automatically option in macOS Sierra is active.
• Increase Token Duration: If feasible, request longer-lived tokens:

  aws sts get-session-token --duration-seconds <Desired_Seconds>

• Monitoring and Alerts: Set up monitoring scripts to alert you before tokens expire, prompting a renewal process.

Summary Table

Conclusion

The Authorization Token has expired issue, while common, is manageable with a thorough understanding of AWS CLI operations and the system dependencies on correct timing. By implementing preventive measures and following the steps outlined above, users can minimize disruptions and maintain seamless AWS operations on macOS Sierra.