Creating a Juju Controller
× Caution! These older versions of Juju documentation are no longer maintained and are provided for reference only. See for the current, supported documentation.

Creating a controller

Use the juju bootstrap command to create a controller (and 'default' model) for a given cloud:

juju bootstrap [options] <cloud name> [<controller name>]

See juju help bootstrap for details on this command or see the Juju command reference page.

The <controller name> is optional. If one is not supplied, then a name is assigned based on the cloud and region.

To learn about configuration options available at bootstrap time, see Configuring controllers and Configuring models.


Constraints may be set during the creation of the controller and are used to set minimum specifications for Juju machines. Constraints that apply to all machines in the models managed by the controller, but excluding the controller itself, are known as model constraints. These are set via the --constraints option. Constraints that apply to solely the controller are known as controller constraints and are set by using the --bootstrap-constraints option. The same values can be used by either type.

For general information on constraints, see Constraints.


Set default model constraints for a given controller

Below, all machines in the LXD controller's models will have at least 4GiB of memory:

juju bootstrap --constraints="mem=4G" localhost

Set controller constraints for a new controller

This example shows how to request at least 4GiB of memory and two CPUs for an AWS controller:

juju bootstrap --bootstrap-constraints="mem=4G cores=2" aws

Create a controller of a specific series

The controller will run the latest LTS Ubuntu release by default. At the time of writing, Xenial will be selected.

For our example, we name the resulting LXD controller 'lxd-xenial' to reflect that:

juju bootstrap localhost lxd-xenial

To select a different series the --bootstrap-series option is used.

Below, a google (GCE) controller based on Ubuntu 14.04 LTS (Trusty) is requested (and is given the name 'gce-trusty'):

juju bootstrap --bootstrap-series=trusty google gce-trusty

Create a Rackspace controller using a daily image

The example uses a previously defined configuration file called config-rackspace.yaml.

Note that values passed using '--config' will take precedence over values included in a file. This is important if you use both a config file and state one or more config values while bootstrapping.

juju bootstrap \
    --config=~/config-rackspace.yaml   \
    --config image-stream=daily        \
    rackspace controller-rackspace

Create a controller using a non-default region

The Clouds page details listing available clouds and how the list denotes default regions for each. To specify a different region during controller creation, use:

juju bootstrap aws/us-west-2 mycontroller

This is an instance where using the default controller name could be especially handy, as omitting the mycontroller name will cause your new controller to be named using the non-default region, specifically naming it aws-us-west-2:

juju bootstrap aws/us-west-2

Create a controller using a different MongoDB profile

MongoDB has two memory profile settings available, 'default' and 'low'. The first setting is the profile shipped by default with MongoDB. The second is a more conservative memory profile that uses less memory. To select which one your controller uses when it is created, use:

juju bootstrap --config mongo-memory-profile=low

Change timeout and retry delays

You can change the default timeout and retry delays used by Juju by setting the following keys in your configuration:

Key Default (seconds) Purpose
bootstrap-timeout 600 How long to wait for a connection to the controller
bootstrap-retry-delay 5 How long to wait between connection attempts to a controller
bootstrap-address-delay 10 How often to refresh controller addresses from the API server

For example, to increase the timeout between the client and the controller from 10 minutes to 15, enter the value in seconds:

juju bootstrap --config bootstrap-timeout=900 localhost lxd-faraway

Changing the current model/controller

By default, when Juju bootstraps a new controller, it will also 'switch' to that controller and the default model created with it. Any subsequent Juju commands which do not specify a controller/model will be assumed to apply to this model.

In some cases (e.g. when scripting Juju) this may not be desirable. It is possible to add a --no-switch option to the bootstrap command to prevent the new controller from being automatically selected. For example:

juju bootstrap --no-switch localhost lxd-new

Configuring/enabling a remote syslog server

Create an Azure controller and configure for log forwarding:

juju bootstrap azure --config logconfig.yaml

To enable forwarding on all the controller's models by default:

juju bootstrap azure --config logforward-enabled=true --config logconfig.yaml

See Remote logging for a more thorough treatment of log forwarding.

Specifying an agent version

When a controller is created, it is possible to influence what agent version will be used across the controller and its models. This is covered in Agent versions and streams.

Passing a cloud-specific setting

View if your chosen backing cloud has any special features and then pass the feature as an option.

Firstly, reveal any features:

juju show-cloud --include-config aws

The bottom portion of the output looks like this:

The available config options specific to ec2 clouds are:
  type: string
  description: Use a specific AWS VPC ID (optional). When not specified, Juju requires
    a default VPC or EC2-Classic features to be available for the account/region.
  type: bool
  description: Force Juju to use the AWS VPC ID specified with vpc-id, when it fails
    the minimum validation criteria. Not accepted without vpc-id

Note: The VPC ID is obtained from the AWS web UI.

Secondly, create the controller by placing it (and its models) within it:

juju boootstrap --config vpc-id=vpc-86f7bbe1 aws

Note: Cloud-specific features can also be passed to individual models during their creation (add-model).