# Error: Couldn't find specified instance profile: ... failed to satisfy constraint (Packer)

## TL;DR
`iam_instance_profile` must be the bare profile name, not a path or ARN. Use `test-profile`, not `/foo/bar/test-profile` or the full ARN.

## The error

```
Build 'amazon-ebs' errored after 20 seconds 62 milliseconds: Couldn't find specified instance profile: ValidationError: 1 validation error detected: Value '/foo/bar/test-profile' at 'instanceProfileName' failed to satisfy constraint: Member must satisfy regular expression pattern: [\w+=,.@-]+
	status code: 400
```

## Fix it

1. Take your instance profile ARN and keep only the last segment: `arn:aws:iam::[account]:instance-profile/foo/bar/test-profile` becomes `test-profile`.
   - Success check: the value contains no `/`.
2. Set `"iam_instance_profile": "test-profile"` in the builder.
   - Success check: the value matches `[\w+=,.@-]+`.
3. If your profile genuinely has a path and Packer will not accept it, duplicate the profile without a path as a workaround.
   - Success check: the build finds the profile.
4. Re-run `packer build`.
   - Success check: the instance launches with the profile attached.

## When to use this
You hit this when the build fails looking up the instance profile, and your value contains `/`.

## When NOT to use this
Do not use this for `UnauthorizedOperation` on `iam:PassRole` (that is a permissions gap on your build identity, not the name format).

## Compatibility
Packer 1.x, amazon-ebs. The constraint comes from the EC2 API.

## Variants
- The same `ValidationError` when passing a full ARN instead of the name
- `Couldn't find specified instance profile` when the profile genuinely does not exist (check the name)

## Root cause
EC2's `instanceProfileName` parameter accepts only the name pattern `[\w+=,.@-]+`, which excludes `/`. Packer passes the value straight through, so paths fail at the AWS API.

## Edge cases
- Profiles *with* paths in their names are valid in IAM but unusable here. The duplicate-without-path workaround is the escape hatch.
- The error surfaces ~20s in, at instance launch, not at validate time.