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[!IMPORTANT]
Documentation Update: Product documentation previously located in /website has moved to the hashicorp/web-unified-docs repository, where all product documentation is now centralized. Please make contributions directly to web-unified-docs, since changes to /website in this repository will not appear on developer.hashicorp.com. ⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️

only and except keywords

The only and except keywords are filters that let you selectively run provisioners and post-processors in your Packer build. You can use the keywords in your Packer templates and as flags on the Packer CLI.

Command line flags

@include 'commands/except.mdx'

@include 'commands/only.mdx'

Templates

You can add the only and except keywords to run or skip provisioners and post-processors for a specific source:

source "amazon-ebs" "first-example" {
}

source "amazon-ebs" "second-example" {
}

source "amazon-ebs" "third-example" {
}

build {
  name = "my_build"
  sources = [
    "source.amazon-ebs.first-example",
  ]
  source "source.amazon-ebs.second-example" {
    // setting the name field allows you to rename the source only for this
    // build section. To match this builder, you need to use
    // second-example-local-name, not second-example
    name = "second-example-local-name"
  }

  provisioner "shell-local" {
    only   = ["amazon-ebs.first-example"]
    inline = ["echo I will only run for the first example source"]
  }

  provisioner "shell-local" {
    except = ["amazon-ebs.second-example-local-name"]
    inline = ["echo I will never run for the second example source"]
  }
}

build {
  sources = [
    "source.amazon-ebs.third-example",
  ]
}

# this file will result in Packer creating three builds named:
#  my_build.amazon-ebs.first-example
#  my_build.amazon-ebs.second-example
#  amazon-ebs.third-example

Note that CLI arguments can be used with a glob operator, using the previous configuration:

• packer build -only 'my_build.*' dir: will only run the builds in blocks named my_build.

• packer build -only '*.amazon-ebs.*' dir: will only run the builds with a source of type amazon-ebs.

• packer build -only '*.second-example-local-name' dir: will only run that specifically named build.

-> Note: In the cli only and except will match against build names (for example:my_build.amazon-ebs.first-example) but in a provisioner they will match on the source name (for example:amazon-ebs.third-example).