# Error: Failed to initialize build "amazon-ebs" (Packer)

## TL;DR
The amazon plugin is not installed. Add the `required_plugins` block and run `packer init .`, or `packer plugins install github.com/hashicorp/amazon` directly.

## The error

```
Error: Failed to initialize build "amazon-ebs"

The builder amazon-ebs is unknown by Packer, and is likely part of a plugin that
is not installed.
You may find the needed plugin along with installation instructions documented
on the Packer integrations page.
```

## Fix it

1. Add the plugin requirement to your template:
   ```hcl
   packer {
     required_plugins {
       amazon = { version = ">= 1.0.0", source = "github.com/hashicorp/amazon" }
     }
   }
   ```
   - Success check: the block is present and the source address is spelled correctly.
2. Run `packer init .` in the template directory.
   - Success check: the plugin downloads and installs.
3. Or install directly: `packer plugins install github.com/hashicorp/amazon`.
   - Success check: `packer plugins installed` lists it.
4. Re-run `packer build`.
   - Success check: the build initializes instead of failing instantly.

## When to use this
You hit this immediately on `packer build` or `packer validate` with Packer 1.10+, before any AWS calls.

## When NOT to use this
Do not use this for `Plugin not found` during `packer init` (that is a download/source problem) or for unknown *source types* in HCL (label mismatch).

## Compatibility
Packer 1.10+. Earlier versions bundled these builders.

## Variants
- `Failed to initialize build "[other-builder]"` for googlecompute, azure-arm, etc. (install the matching plugin)
- The same error in CI where `packer init` was skipped

## Root cause
Packer 1.10 removed the bundled builders. Every builder now comes from a plugin that must be installed via `packer init` or `packer plugins install`.

## Edge cases
- `packer init` must run in the directory with the templates, or point it at the right path.
- Version constraints that match nothing produce a different (download) error. Keep them satisfiable.