Error: Build 'amazon-ebs' errored: error validating regions: MissingEndpoint

Error: Build 'amazon-ebs' errored: error validating regions: MissingEndpoint

TL;DR

The AWS SDK cannot resolve an endpoint for the region. Check the region value is valid and that no custom endpoint override is misconfigured; then rebuild.

The error

Build 'amazon-ebs' errored after 844 microseconds: error validating regions: MissingEndpoint: 'Endpoint' configuration is required for this service

Fix it

1. Verify region is a real AWS region string (e.g. us-east-1), not empty or a placeholder.

• Success check: the value matches the AWS region list.

1. If you set a custom endpoint (for LocalStack, VPC endpoints, or other S3-compatible targets), confirm it is a complete URL including scheme.

• Success check: the endpoint parses as a URL.

1. Remove any stale AWS_ENDPOINT_URL or shared-config endpoint overrides leaking into the build environment.

• Success check: env | grep -i endpoint shows nothing unexpected.

1. Re-run packer build.

• Success check: the build gets past region validation.

When to use this

You hit this within milliseconds of build start, before any instance or AMI activity.

When NOT to use this

Do not use this for Unknown region (baked-in region list) or credential errors. This is specifically endpoint resolution.

Compatibility

Packer 1.x, amazon builders, AWS SDK endpoint resolution.

Variants

• MissingEndpoint on other AWS services Packer calls (EC2, SSM)
• The error appearing only in certain environments (env var leakage)

Root cause

The SDK builds service endpoints from the region plus any overrides. An empty region, a bad override, or a conflicting env var leaves it with no endpoint to call.

Edge cases

• The 844-microsecond timing is the tell: this fails before any network I/O, so it is configuration, not connectivity.
• GovCloud/China partitions need the right partition endpoints; a standard-region config fails there.