Deployment

The correct answer is to verify that a consistent user identifier is being passed in the evaluation context, as the same identifier results in the same variant assignment due to deterministic hashing.

AWS AppConfig feature flags use deterministic hashing when performing percentage-based variant allocation. This means that for a given user identifier, the system will always return the same variant. This is by design to ensure a consistent user experience - you don't want a user to flip between variants on each request.

The key insight here is that if the team is not passing a unique user identifier (or is passing the same identifier for all non-enterprise users, or no identifier at all), the deterministic hash will produce the same result every time, causing all users to receive the same variant ('sms_only' in this case). The 50/50 split only works correctly when different user identifiers are passed, allowing the hash function to distribute users across variants.

The other options are incorrect:

• Checking the deployment strategy growth factor is not relevant here. The deployment strategy controls how quickly a new configuration is rolled out to hosts, not how percentage-based variant allocation works. The team already confirmed deployment was successful.

• The configuration format (JSON vs YAML) does not affect percentage allocation functionality. AWS AppConfig supports both formats, and the team confirmed the configuration syntax is valid. Format choice does not impact how percentage splits are calculated.

• The AppConfig Lambda extension polling interval has no relationship to variant calculation completion. The extension caches configuration data locally, and variant evaluation is a fast, synchronous operation that doesn't depend on polling timing. This would cause configuration staleness issues, not consistent single-variant assignment.

The correct approach is to delete the existing test environment and create a new one using the --import-vpc-id flag to reference the pre-provisioned VPC with multi-AZ NAT Gateways, then redeploy the services.

AWS Copilot does not support in-place modification of the underlying VPC infrastructure for an existing environment. The VPC configuration is a foundational infrastructure component that is determined at environment creation time. Once an environment is created with a specific VPC (either Copilot-managed or imported), changing to a different VPC requires recreating the environment.

The --import-vpc-id flag during 'copilot env init' allows you to specify an existing VPC that has already been provisioned outside of Copilot. This is the correct mechanism to use pre-existing networking infrastructure including VPCs with NAT Gateways in multiple Availability Zones.

The second option is incorrect because modifying the manifest.yml file to add a VPC ID will not work for an already-deployed environment. The VPC association is immutable after environment creation, and copilot env deploy cannot change the underlying VPC infrastructure.

The third option is incorrect because copilot env override is used for customizing CloudFormation templates with additional resources or modifications, but it cannot change the fundamental VPC association of an existing environment. VPC changes of this magnitude are not supported through overrides.

The fourth option is incorrect because there is no --override-vpc-id parameter for copilot env init. Additionally, copilot env init is used to create new environments, not modify existing ones, and there is no in-place VPC replacement capability in Copilot.

The correct answer is to verify that the development endpoint is configured with the same VPC, subnet, and security group that allow communication with the Redshift cluster subnet.

When an AWS Glue development endpoint is created within a VPC, it requires proper network configuration including VPC, subnet, and security group settings. The 'connection refused' error after 30 seconds is a classic symptom of network connectivity issues, not authentication or driver problems.

The key insight here is that even though the Redshift security group allows inbound traffic from the VPC CIDR range, the Glue development endpoint's security group must also allow outbound traffic to the Redshift cluster on port 5439. Additionally, the endpoint must be in a subnet that can route to the Redshift cluster's subnet. The fact that EC2 instances in the same subnet can connect to Redshift but the Glue endpoint cannot strongly suggests the endpoint may be configured with different network settings.

The second option about enhanced VPC routing and NAT Gateway bandwidth is incorrect because enhanced VPC routing affects how Redshift routes traffic for COPY/UNLOAD operations, not inbound JDBC connections. NAT Gateway bandwidth wouldn't cause a 'connection refused' error.

The third option about IAM permissions and Glue Connection is incorrect because the error is 'connection refused' which is a network-level issue, not an authentication or authorization error. IAM credential issues would result in different error messages related to authentication failures.

The fourth option about JDBC driver versions and Spark connector libraries is incorrect because driver or library issues would result in class not found errors or compatibility exceptions, not 'connection refused' network errors.