packer-cn/website/source/docs/builders/null.html.markdown

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layout: "docs"
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# Null Builder

Type: `null`

The null builder is not really a builder, it just setups a SSH connection
and runs the provisioners. It can be used to debug provisioners without
incurring high wait times. It does not create any kind of image or artifact.

## Basic Example

Below is a fully functioning example. It doesn't do anything useful, since
no provisioners are defined, but it will connect to the specified host via ssh.

<pre class="prettyprint">
{
  "type":     "null",
  "host":     "127.0.0.1",
  "username": "foo",
  "password": "bar"
}
</pre>

## Configuration Reference

Configuration options are organized below into two categories: required and
optional. Within each category, the available options are alphabetized and
described.

### Required:

* `host` (string) - The hostname or IP address to connect to.

* `ssh_password` (string) - The password to be used for the ssh connection.
  Cannot be combined with ssh_private_key_file.

* `ssh_private_key_file` (string) - The filename of the ssh private key to be
  used for the ssh connection. E.g. /home/user/.ssh/identity_rsa.

* `ssh_username` (string) - The username to be used for the ssh connection.

### Optional:

* `port` (integer) - ssh port to connect to, defaults to 22.