Ansible Provisioner

Type: ansible

The ansible Packer provisioner runs Ansible playbooks. It dynamically creates an Ansible inventory file configured to use SSH, runs an SSH server, executes ansible-playbook, and marshals Ansible plays through the SSH server to the machine being provisioned by Packer.

Basic Example

This is a fully functional template that will provision an image on DigitalOcean. Replace the mock api_token value with your own.

Example Packer template:

{
  "provisioners": [
    {
      "type": "ansible",
      "playbook_file": "./playbook.yml"
    }
  ],

  "builders": [
    {
      "type": "digitalocean",
      "api_token": "6a561151587389c7cf8faa2d83e94150a4202da0e2bad34dd2bf236018ffaeeb",
      "image": "ubuntu-14-04-x64",
      "region": "sfo1"
    }
  ]
}

Example playbook:

---
# playbook.yml
- name: 'Provision Image'
  hosts: default
  become: true

  tasks:
    - name: install Apache
      package:
        name: 'httpd'
        state: present

Configuration Reference

Required Parameters:

• playbook_file (string) - The playbook to be run by Ansible.

Optional Parameters:

• ansible_env_vars (array of strings) - Environment variables to set before running Ansible. Usage example:

    "ansible_env_vars": [ "ANSIBLE_HOST_KEY_CHECKING=False", "ANSIBLE_SSH_ARGS='-o ForwardAgent=yes -o ControlMaster=auto -o ControlPersist=60s'", "ANSIBLE_NOCOLOR=True" ]
  

  This is a template engine. Therefore, you may use user variables and template functions in this field.

  For example, if you are running a Windows build on AWS, Azure, Google Compute, or OpenStack and would like to access the auto-generated password that Packer uses to connect to a Windows instance via WinRM, you can use the template variable {{.WinRMPassword}} in this option. Example:

  "ansible_env_vars": [ "WINRM_PASSWORD={{.WinRMPassword}}" ],
  

• command (string) - The command to invoke ansible. Defaults to ansible-playbook. If you would like to provide a more complex command, for example, something that sets up a virtual environment before calling ansible, take a look at the ansible wrapper guide below for inspiration.

• empty_groups (array of strings) - The groups which should be present in inventory file but remain empty.

• extra_arguments (array of strings) - Extra arguments to pass to Ansible. These arguments will not be passed through a shell and arguments should not be quoted. Usage example:

    "extra_arguments": [ "--extra-vars", "Region={{user `Region`}} Stage={{user `Stage`}}" ]
  

  If you are running a Windows build on AWS, Azure, Google Compute, or OpenStack and would like to access the auto-generated password that Packer uses to connect to a Windows instance via WinRM, you can use the template variable {{.WinRMPassword}} in this option. For example:

    "extra_arguments": [
      "--extra-vars", "winrm_password={{ .WinRMPassword }}"
    ]
  

• galaxy_file (string) - A requirements file which provides a way to install roles with the ansible-galaxy cli on the local machine before executing ansible-playbook. By default, this is empty.

• galaxy_command (string) - The command to invoke ansible-galaxy. By default, this is ansible-galaxy.

• galaxy_force_install (bool) - Force overwriting an existing role. Adds --force option to ansible-galaxy command. By default, this is false.

• groups (array of strings) - The groups into which the Ansible host should be placed. When unspecified, the host is not associated with any groups.

• host_alias (string) - The alias by which the Ansible host should be known. Defaults to default. This setting is ignored when using a custom inventory file.

• inventory_file (string) - The inventory file to use during provisioning. When unspecified, Packer will create a temporary inventory file and will use the host_alias.

• inventory_directory (string) - The directory in which to place the temporary generated Ansible inventory file. By default, this is the system-specific temporary file location. The fully-qualified name of this temporary file will be passed to the -i argument of the ansible command when this provisioner runs ansible. Specify this if you have an existing inventory directory with host_vars group_vars that you would like to use in the playbook that this provisioner will run.

• keep_inventory_file (boolean) - If true, the Ansible provisioner will not delete the temporary inventory file it creates in order to connect to the instance. This is useful if you are trying to debug your ansible run and using "--on-error=ask" in order to leave your instance running while you test your playbook. this option is not used if you set an inventory_file.

• local_port (uint) - The port on which to attempt to listen for SSH connections. This value is a starting point. The provisioner will attempt listen for SSH connections on the first available of ten ports, starting at local_port. A system-chosen port is used when local_port is missing or empty.

• roles_path (string) - The path to the directory on your local system to install the roles in. Adds --roles-path /path/to/your/roles to ansible-galaxy command. By default, this is empty, and thus --roles-path option is not added to the command.

• sftp_command (string) - The command to run on the machine being provisioned by Packer to handle the SFTP protocol that Ansible will use to transfer files. The command should read and write on stdin and stdout, respectively. Defaults to /usr/lib/sftp-server -e.

• skip_version_check (boolean) - Check if ansible is installed prior to running. Set this to true, for example, if you're going to install ansible during the packer run.

• ssh_host_key_file (string) - The SSH key that will be used to run the SSH server on the host machine to forward commands to the target machine. Ansible connects to this server and will validate the identity of the server using the system known_hosts. The default behavior is to generate and use a onetime key. Host key checking is disabled via the ANSIBLE_HOST_KEY_CHECKING environment variable if the key is generated.

• ssh_authorized_key_file (string) - The SSH public key of the Ansible ssh_user. The default behavior is to generate and use a onetime key. If this key is generated, the corresponding private key is passed to ansible-playbook with the -e ansible_ssh_private_key_file option.

• user (string) - The ansible_user to use. Defaults to the user running packer, NOT the user set for your communicator. If you want to use the same user as the communicator, you will need to manually set it again in this field.

• use_proxy (boolean) - When true, set up a localhost proxy adapter so that Ansible has an IP address to connect to, even if your guest does not have an IP address. For example, the adapter is necessary for Docker builds to use the Ansible provisioner. If you set this option to false, but Packer cannot find an IP address to connect Ansible to, it will automatically set up the adapter anyway.

  In order for Ansible to connect properly even when use_proxy is false, you need to make sure that you are either providing a valid username and ssh key to the ansible provisioner directly, or that the username and ssh key being used by the ssh communicator will work for your needs. If you do not provide a user to ansible, it will use the user associated with your builder, not the user running Packer.

  use_proxy=false is currently only supported for SSH and WinRM.

  Currently, this defaults to true for all connection types. In the future, this option will be changed to default to false for SSH and WinRM connections where the provisioner has access to a host IP.

Parameters common to all provisioners:

• pause_before (duration) - Sleep for duration before execution.

• max_retries (int) - Max times the provisioner will retry in case of failure. Defaults to zero (0). Zero means an error will not be retried.

• only (array of string) - Only run the provisioner for listed builder(s) by name.

• override (object) - Override the builder with different settings for a specific builder, eg :

  {
    "type": "shell",
    "script": "script.sh",
    "override": {
      "vmware-iso": {
        "execute_command": "echo 'password' | sudo -S bash {{.Path}}"
      }
    }
  }
  

• timeout (duration) - If the provisioner takes more than for example 1h10m1s or 10m to finish, the provisioner will timeout and fail.

Default Extra Variables

In addition to being able to specify extra arguments using the extra_arguments configuration, the provisioner automatically defines certain commonly useful Ansible variables:

• packer_build_name is set to the name of the build that Packer is running. This is most useful when Packer is making multiple builds and you want to distinguish them slightly when using a common playbook.

• packer_builder_type is the type of the builder that was used to create the machine that the script is running on. This is useful if you want to run only certain parts of the playbook on systems built with certain builders.

• packer_http_addr If using a builder that provides an http server for file transfer (such as hyperv, parallels, qemu, virtualbox, and vmware), this will be set to the address. You can use this address in your provisioner to download large files over http. This may be useful if you're experiencing slower speeds using the default file provisioner. A file provisioner using the winrm communicator may experience these types of difficulties.

Debugging

To debug underlying issues with Ansible, add "-vvvv" to "extra_arguments" to enable verbose logging.

  "extra_arguments": [ "-vvvv" ]

Limitations

Redhat / CentOS

Redhat / CentOS builds have been known to fail with the following error due to sftp_command, which should be set to /usr/libexec/openssh/sftp-server -e:

==> virtualbox-ovf: starting sftp subsystem
    virtualbox-ovf: fatal: [default]: UNREACHABLE! => {"changed": false, "msg": "SSH Error: data could not be sent to the remote host. Make sure this host can be reached over ssh", "unreachable": true}

chroot communicator

Building within a chroot (e.g. amazon-chroot) requires changing the Ansible connection to chroot and running Ansible as root/sudo.

{
  "builders": [
    {
      "type": "amazon-chroot",
      "mount_path": "/mnt/packer-amazon-chroot",
      "region": "us-east-1",
      "source_ami": "ami-123456"
    }
  ],
  "provisioners": [
    {
      "type": "ansible",
      "extra_arguments": [
        "--connection=chroot",
        "--inventory-file=/mnt/packer-amazon-chroot,"
      ],
      "playbook_file": "main.yml"
    }
  ]
}

WinRM Communicator

There are two possible methods for using ansible with the WinRM communicator.

Method 1 (recommended)

The recommended way to use the WinRM communicator is to set "use_proxy": false and let the Ansible provisioner handle the rest for you. If you are using WinRM with HTTPS, and you are using a self-signed certificate you will also have to set ansible_winrm_server_cert_validation=ignore in your extra_arguments.

Below is a fully functioning Ansible example using WinRM:

{
  "builders": [
  {
    "type": "amazon-ebs",
    "region": "us-east-1",
    "instance_type": "t2.micro",
      "source_ami_filter": {
        "filters": {
          "virtualization-type": "hvm",
          "name": "*Windows_Server-2012*English-64Bit-Base*",
          "root-device-type": "ebs"
        },
        "most_recent": true,
        "owners": "amazon"
      },
    "ami_name": "default-packer",
    "user_data_file": "windows_bootstrap.txt",
    "communicator": "winrm",
    "force_deregister": true,
    "winrm_insecure": true,
    "winrm_username": "Administrator",
    "winrm_use_ssl": true
  }],
  "provisioners": [
    {
      "type":  "ansible",
      "playbook_file": "./playbook.yml",
      "user": "Administrator",
      "use_proxy": false,
      "extra_arguments": [
        "-e", "ansible_winrm_server_cert_validation=ignore"
      ]
    }
  ]
}

Note that you do have to set the "Administrator" user, because otherwise Ansible will default to using the user that is calling Packer, rather than the user configured inside of the Packer communicator. For the contents of windows_bootstrap.txt, see the winrm docs for the amazon-ebs communicator.

When running from OSX, you may see an error like:

    amazon-ebs: objc[9752]: +[__NSCFConstantString initialize] may have been in progress in another thread when fork() was called.
    amazon-ebs: objc[9752]: +[__NSCFConstantString initialize] may have been in progress in another thread when fork() was called. We cannot safely call it or ignore it in the fork() child process. Crashing instead. Set a breakpoint on objc_initializeAfterForkError to debug.
    amazon-ebs: ERROR! A worker was found in a dead state

If you see this, you may be able to work around the issue by telling Ansible to explicitly not use any proxying; you can do this by setting the template option

"ansible_env_vars": ["no_proxy=\"*\""],

in the above Ansible template.

Method 2 (Not recommended)

If you want to use the Packer ssh proxy, then you need a custom Ansible connection plugin and a particular configuration. You need a directory named connection_plugins next to the playbook which contains a file named packer.py` which implements the connection plugin. On versions of Ansible before 2.4.x, the following works as the connection plugin:

from __future__ import (absolute_import, division, print_function)
__metaclass__ = type

from ansible.plugins.connection.ssh import Connection as SSHConnection

class Connection(SSHConnection):
    ''' ssh based connections for powershell via packer'''

    transport = 'packer'
    has_pipelining = True
    become_methods = []
    allow_executable = False
    module_implementation_preferences = ('.ps1', '')

    def __init__(self, *args, **kwargs):
        super(Connection, self).__init__(*args, **kwargs)

Newer versions of Ansible require all plugins to have a documentation string. You can see if there is a plugin available for the version of Ansible you are using here.

To create the plugin yourself, you will need to copy all of the options from the DOCUMENTATION string from the ssh.py Ansible connection plugin of the Ansible version you are using and add it to a packer.py file similar to as follows

from __future__ import (absolute_import, division, print_function)
__metaclass__ = type

from ansible.plugins.connection.ssh import Connection as SSHConnection

DOCUMENTATION = '''
    connection: packer
    short_description: ssh based connections for powershell via packer
    description:
        - This connection plugin allows ansible to communicate to the target packer machines via ssh based connections for powershell.
    author: Packer
    version_added: na
    options:
      **** Copy ALL the options from
      https://github.com/ansible/ansible/blob/devel/lib/ansible/plugins/connection/ssh.py
      for the version of Ansible you are using ****
'''

class Connection(SSHConnection):
    ''' ssh based connections for powershell via packer'''

    transport = 'packer'
    has_pipelining = True
    become_methods = []
    allow_executable = False
    module_implementation_preferences = ('.ps1', '')

    def __init__(self, *args, **kwargs):
        super(Connection, self).__init__(*args, **kwargs)

This template should build a Windows Server 2012 image on Google Cloud Platform:

{
  "variables": {},
  "provisioners": [
    {
      "type": "ansible",
      "playbook_file": "./win-playbook.yml",
      "extra_arguments": [
        "--connection",
        "packer",
        "--extra-vars",
        "ansible_shell_type=powershell ansible_shell_executable=None"
      ]
    }
  ],
  "builders": [
    {
      "type": "googlecompute",
      "account_file": "{{ user `account_file`}}",
      "project_id": "{{user `project_id`}}",
      "source_image": "windows-server-2012-r2-dc-v20160916",
      "communicator": "winrm",
      "zone": "us-central1-a",
      "disk_size": 50,
      "winrm_username": "packer",
      "winrm_use_ssl": true,
      "winrm_insecure": true,
      "metadata": {
        "sysprep-specialize-script-cmd": "winrm set winrm/config/service/auth @{Basic=\"true\"}"
      }
    }
  ]
}

Post i/o timeout errors

If you see unknown error: Post http://<ip>:<port>/wsman:dial tcp <ip>:<port>: i/o timeout errors while provisioning a Windows machine, try setting Ansible to copy files over ssh instead of sftp.

Too many SSH keys

SSH servers only allow you to attempt to authenticate a certain number of times. All of your loaded keys will be tried before the dynamically generated key. If you have too many SSH keys loaded in your ssh-agent, the Ansible provisioner may fail authentication with a message similar to this:

    googlecompute: fatal: [default]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: Warning: Permanently added '[127.0.0.1]:62684' (RSA) to the list of known hosts.\r\nReceived disconnect from 127.0.0.1 port 62684:2: too many authentication failures\r\nAuthentication failed.\r\n", "unreachable": true}

To unload all keys from your ssh-agent, run:

$ ssh-add -D

Become: yes

We recommend against running Packer as root; if you do then you won't be able to successfully run your ansible playbook as root; become: yes will fail.

Using a wrapping script for your ansible call

Sometimes, you may have extra setup that needs to be called as part of your ansible run. The easiest way to do this is by writing a small bash script and using that bash script in your "command" in place of the default "ansible-playbook". For example, you may need to launch a Python virtualenv before calling ansible. To do this, you'd want to create a bash script like

#!/bin/bash
source /tmp/venv/bin/activate && ANSIBLE_FORCE_COLOR=1 PYTHONUNBUFFERED=1 /tmp/venv/bin/ansible-playbook "$@"

The ansible provisioner template remains very simple. For example:

{
  "type": "ansible",
  "command": "/Path/To/call_ansible.sh",
  "playbook_file": "./playbook.yml"
}

Note that we're calling ansible-playbook at the end of this command and passing all command line arguments through into this call; this is necessary for making sure that --extra-vars and other important ansible arguments get set. Note the quoting around the bash array, too; if you don't use quotes, any arguments with spaces will not be read properly.

Docker

When trying to use Ansible with Docker, you need to tweak a few options.

• Change the ansible_connection from "ssh" to "docker"
• Set a Docker container name via the --name option.

On a CI server you probably want to overwrite ansible_host with a random name.

Example Packer template:

{
  "variables": {
    "ansible_host": "default",
    "ansible_connection": "docker"
  },
  "builders":[
    {
      "type": "docker",
      "image": "centos:7",
      "commit": true,
      "run_command": [ "-d", "-i", "-t", "--name", "{{user `ansible_host`}}", "{{.Image}}", "/bin/bash" ]
    }
  ],
  "provisioners": [
    {
      "type": "ansible",
      "groups": [ "webserver" ],
      "playbook_file": "./webserver.yml",
      "extra_arguments": [
        "--extra-vars",
        "ansible_host={{user `ansible_host`}} ansible_connection={{user `ansible_connection`}}"
      ]
    }
  ]
}

Example playbook:

- name: configure webserver
  hosts: webserver
  tasks:
    - name: install Apache
      yum:
        name: httpd

Troubleshooting

If you are using an Ansible version >= 2.8 and Packer hangs in the "Gathering Facts" stage, this could be the result of a pipelineing issue with the proxy adapter that Packer uses. Setting use_proxy: false, in your Packer config should resolve the issue. In the future we will default to setting this, so you won't have to but for now it is a manual change you must make.