How Do I Debug This Error: Rpc Error: Code = Unknown Desc = Unable to Validate AWS Credentials

Introduction

When working with Infrastructure as Code (IaC) tools like Pulumi that interact with AWS, you might encounter the error: “rpc error: code = Unknown desc = unable to validate AWS credentials”. This error occurs when Pulumi cannot validate the AWS credentials needed to authenticate with AWS services. In this guide, we’ll explain how to diagnose and resolve this common issue.

What’s Actually Happening?

This error message indicates that Pulumi cannot find or validate the AWS credentials necessary to authenticate with AWS services. AWS credentials typically consist of an access key ID, a secret access key, and sometimes a session token. These credentials must be valid and accessible to Pulumi to allow it to make API calls to AWS services.

Common Causes

1. Missing or Invalid Credentials: Your AWS credentials may be missing, expired, or invalid.
2. Configuration Issues: There may be issues with how your AWS credentials are configured.
3. Environment Variables vs. Configuration Files: Using the wrong method to provide credentials can lead to conflicts.
4. Permissions Issues: Your AWS credentials may lack the necessary permissions.
5. Instance Metadata Service Issues: If running on an EC2 instance, there may be issues accessing the instance metadata service.

Explanation

Step 1: Verify Your AWS Credentials Source

AWS credentials can be provided in multiple ways:

1. Environment Variables:

   export AWS_ACCESS_KEY_ID=your_access_key
   export AWS_SECRET_ACCESS_KEY=your_secret_key
   export AWS_REGION=your_region
   export AWS_PROFILE=your_profile_name  # If using profiles
   

2. AWS Configuration Files:

   • ~/.aws/credentials for credentials
   • ~/.aws/config for configuration

3. Configuration: In Pulumi, for example, you can set:

   pulumi config set aws:region us-west-2
   pulumi config set aws:profile my-profile
   

Step 2: Check for Credential Conflicts

One common issue is having conflicts between different credential sources. For example, if you previously used environment variables like AWS_PROFILE and AWS_REGION but then switched to Pulumi configuration settings, you might encounter validation errors.

Make sure you’re consistently using one method to provide credentials:

• If using environment variables, ensure they’re correctly set
• If using configuration settings, ensure environment variables are unset to avoid conflicts
• If using AWS profiles, ensure they’re correctly configured in your AWS files

You can see your current AWS environment variables with:

echo $AWS_ACCESS_KEY_ID
echo $AWS_SECRET_ACCESS_KEY
echo $AWS_SESSION_TOKEN
echo $AWS_REGION
echo $AWS_PROFILE

Step 3: Validate AWS Credentials Directly

Test your AWS credentials directly using the AWS CLI:

aws sts get-caller-identity

Wrapping Up

AWS credential errors can be frustrating but are usually straightforward to resolve once you understand the source of the issue. Most commonly, the problem stems from credential conflicts or misconfiguration. By systematically checking each credential source and ensuring consistency, you can quickly get back to deploying your infrastructure.

Remember that AWS credentials are sensitive information. Always follow security best practices by using IAM roles where possible, rotating credentials regularly, and never committing credentials to source control.