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layout	page_title	sidebar_current	description
language	Provisioner Connection Settings	docs-provisioners-connection	Managing provisioner connection defaults for SSH and WinRM using the `connection` block in Terraform language.

Provisioner Connection Settings

Most provisioners require access to the remote resource via SSH or WinRM, and expect a nested connection block with details about how to connect.

-> Note: Provisioners should only be used as a last resort. For most common situations there are better alternatives. For more information, see the main Provisioners page.

-> Note: In Terraform 0.11 and earlier, providers could set default values for some connection settings, so that connection blocks could sometimes be omitted. This feature was removed in 0.12 in order to make Terraform's behavior more predictable.

-> Note: Since the SSH connection type is most often used with newly-created remote resources, validation of SSH host keys is disabled by default. In scenarios where this is not acceptable, a separate mechanism for key distribution could be established and the host_key directive documented below explicitly set to verify against a specific key or signing CA.

Connection blocks don't take a block label, and can be nested within either a resource or a provisioner.

A connection block nested directly within a resource affects all of that resource's provisioners.
A connection block nested in a provisioner block only affects that provisioner, and overrides any resource-level connection settings.

One use case for providing multiple connections is to have an initial provisioner connect as the root user to set up user accounts, and have subsequent provisioners connect as a user with more limited permissions.

Example usage

# Copies the file as the root user using SSH
provisioner "file" {
  source      = "conf/myapp.conf"
  destination = "/etc/myapp.conf"

  connection {
    type     = "ssh"
    user     = "root"
    password = "${var.root_password}"
    host     = "${var.host}"
  }
}

# Copies the file as the Administrator user using WinRM
provisioner "file" {
  source      = "conf/myapp.conf"
  destination = "C:/App/myapp.conf"

  connection {
    type     = "winrm"
    user     = "Administrator"
    password = "${var.admin_password}"
    host     = "${var.host}"
  }
}

The `self` Object

Expressions in connection blocks cannot refer to their parent resource by name. Instead, they can use the special self object.

The self object represents the connection's parent resource, and has all of that resource's attributes. For example, use self.public_ip to reference an aws_instance's public_ip attribute.

-> Technical note: Resource references are restricted here because references create dependencies. Referring to a resource by name within its own block would create a dependency cycle.

Argument Reference

The following arguments are supported by all connection types:

type - The connection type that should be used. Valid types are ssh and winrm. Defaults to ssh.
user - The user that we should use for the connection. Defaults to root when using type ssh and defaults to Administrator when using type winrm.
password - The password we should use for the connection. In some cases this is specified by the provider.
host - (Required) The address of the resource to connect to.
port - The port to connect to. Defaults to 22 when using type ssh and defaults to 5985 when using type winrm.
timeout - The timeout to wait for the connection to become available. Should be provided as a string like 30s or 5m. Defaults to 5 minutes.
script_path - The path used to copy scripts meant for remote execution.

Additional arguments only supported by the ssh connection type:

private_key - The contents of an SSH key to use for the connection. These can be loaded from a file on disk using the file function. This takes preference over the password if provided.
certificate - The contents of a signed CA Certificate. The certificate argument must be used in conjunction with a private_key. These can be loaded from a file on disk using the the file function.
agent - Set to false to disable using ssh-agent to authenticate. On Windows the only supported SSH authentication agent is Pageant.
agent_identity - The preferred identity from the ssh agent for authentication.
host_key - The public key from the remote host or the signing CA, used to verify the connection.
target_platform - The target platform to connect to. Valid values are windows and unix. Defaults to unix if not set.

If the platform is set to windows, the default script_path is c:\windows\temp\terraform_%RAND%.cmd, assuming the SSH default shell is cmd.exe. If the SSH default shell is PowerShell, set script_path to "c:/windows/temp/terraform_%RAND%.ps1"

Additional arguments only supported by the winrm connection type:

https - Set to true to connect using HTTPS instead of HTTP.
insecure - Set to true to not validate the HTTPS certificate chain.
use_ntlm - Set to true to use NTLM authentication, rather than default (basic authentication), removing the requirement for basic authentication to be enabled within the target guest. Further reading for remote connection authentication can be found here.
cacert - The CA certificate to validate against.

Connecting through a Bastion Host with SSH

The ssh connection also supports the following fields to facilitate connnections via a bastion host.

bastion_host - Setting this enables the bastion Host connection. This host will be connected to first, and then the host connection will be made from there.
bastion_host_key - The public key from the remote host or the signing CA, used to verify the host connection.
bastion_port - The port to use connect to the bastion host. Defaults to the value of the port field.
bastion_user - The user for the connection to the bastion host. Defaults to the value of the user field.
bastion_password - The password we should use for the bastion host. Defaults to the value of the password field.
bastion_private_key - The contents of an SSH key file to use for the bastion host. These can be loaded from a file on disk using the file function. Defaults to the value of the private_key field.
bastion_certificate - The contents of a signed CA Certificate. The certificate argument must be used in conjunction with a bastion_private_key. These can be loaded from a file on disk using the the file function.

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