This section has been tested for Horizon on Ubuntu (12.04-64) and RPM-based (RHEL 7.x) distributions. Feel free to add notes and any changes according to your experiences or operating system.

Linux Systems

Install the prerequisite packages.

On Ubuntu:

> sudo apt-get install git python-dev python-virtualenv libssl-dev libffi-dev

On RPM-based distributions (e.g., Fedora/RHEL/CentOS/Scientific Linux):

> sudo yum install gcc git-core python-devel python-virtualenv openssl-devel libffi-devel which


To setup a Horizon development environment simply clone the Horizon git repository from http://github.com/openstack/horizon and execute the run_tests.sh script from the root folder (see The run_tests.sh Script):

> git clone https://github.com/openstack/horizon.git
> cd horizon
> ./run_tests.sh


Running run_tests.sh will build a virtualenv, .venv, where all the python dependencies for Horizon are installed and referenced. After the dependencies are installed, the unit test suites in the Horizon repo will be executed. There should be no errors from the tests.

Next you will need to setup your Django application config by copying openstack_dashboard/local/local_settings.py.example to openstack_dashboard/local/local_settings.py. To do this quickly you can use the following command:

> cp openstack_dashboard/local/local_settings.py.example openstack_dashboard/local/local_settings.py


To add new settings or customize existing settings, modify the local_settings.py file.

Horizon assumes a single end-point for OpenStack services which defaults to the local host (, as is the default in DevStack. If this is not the case change the OPENSTACK_HOST setting in the openstack_dashboard/local/local_settings.py file, to the actual IP address of the OpenStack end-point Horizon should use.

You can save changes you made to openstack_dashboard/local/local_settings.py with the following command:

> python manage.py migrate_settings --gendiff


This creates a local_settings.diff file which is a diff between local_settings.py and local_settings.py.example

If you upgrade Horizon, you might need to update your openstack_dashboard/local/local_settings.py file with new parameters from openstack_dashboard/local/local_settings.py.example to do so, first update Horizon:

> git remote update && git pull --ff-only origin master

Then update your openstack_dashboard/local/local_settings.py file:

> mv openstack_dashboard/local/local_settings.py openstack_dashboard/local/local_settings.py.old
> python manage.py migrate_settings


This applies openstack_dashboard/local/local_settings.diff on openstack_dashboard/local/local_settings.py.example to regenerate an openstack_dashboard/local/local_settings.py file. The migration can sometimes have difficulties to migrate some settings, if this happens you will be warned with a conflict message pointing to an openstack_dashboard/local/local_settings.py_Some_DateTime.rej file. In this file, you will see the lines which could not be automatically changed and you will have to redo only these few changes manually instead of modifying the full openstack_dashboard/local/local_settings.py.example file.

When all settings have been migrated, it is safe to regenerate a clean diff in order to prevent Conflicts for future migrations:

> mv openstack_dashboard/local/local_settings.diff openstack_dashboard/local/local_settings.diff.old
> python manage.py migrate_settings --gendiff

To start the Horizon development server use run_tests.sh:

> ./run_tests.sh --runserver localhost:9000


The default port for runserver is 8000 which is already consumed by heat-api-cfn in DevStack. If not running in DevStack ./run_tests.sh –runserver will start the test server at http://localhost:8000.


The run_tests.sh script provides wrappers around manage.py. For more information on manage.py which is a django, see https://docs.djangoproject.com/en/dev/ref/django-admin/

Once the Horizon server is running, point a web browser to http://localhost:9000 or to the IP and port the server is listening for.


The DevStack project (http://devstack.org/) can be used to install an OpenStack development environment from scratch. For a local.conf that enables most services that Horizon supports managing see local.conf


The minimum required set of OpenStack services running includes the following:

  • Nova (compute, api, scheduler, and network)
  • Glance
  • Keystone
  • Neutron (unless nova-network is used)

Horizon provides optional support for other services. See System Requirements for the supported services. If Keystone endpoint for a service is configured, Horizon detects it and enables its support automatically.

Editing Horizon’s Source

Although DevStack installs and configures an instance of Horizon when running stack.sh, the preferred development setup follows the instructions above on the server/VM running DevStack. There are several advantages to maintaining a separate copy of the Horizon repo, rather than editing the devstack installed copy.

  • Source code changes aren’t as easily lost when running unstack.sh/stack.sh
  • The development server picks up source code changes (other than JavaScript and CSS due to compression and compilation) while still running.
  • Log messages and print statements go directly to the console.
  • Debugging with pdb becomes much simpler to interact with.


JavaScript and CSS changes require a development server restart. Also, forcing a refresh of the page (e.g. using Shift-F5) in the browser is required to pull down non-cached versions of the CSS and JavaScript. The default setting in Horizon is to do compilation and compression of these files at server startup. If you have configured your local copy to do offline compression, more steps are required.

Horizon’s Structure

This project is a bit different from other OpenStack projects in that it has two very distinct components underneath it: horizon, and openstack_dashboard.

The horizon directory holds the generic libraries and components that can be used in any Django project.

The openstack_dashboard directory contains a reference Django project that uses horizon.

For development, both pieces share an environment which (by default) is built with the tools/install_venv.py script. That script creates a virtualenv and installs all the necessary packages.

If dependencies are added to either horizon or openstack_dashboard, they should be added to requirements.txt.


Dashboard configuration

To add a new dashboard to your project, you need to add a configuration file to openstack_dashboard/local/enabled directory. For more information on this, see Pluggable Settings.

There is also an alternative way to add a new dashboard, by adding it to Django’s INSTALLED_APPS setting. For more information about this, see dashboards. However, please note that the recommended way is to take advantage of the pluggable settings feature.


Then you add a single line to your project’s urls.py:

url(r'', include(horizon.urls)),

Those urls are automatically constructed based on the registered Horizon apps. If a different URL structure is desired it can be constructed by hand.


Pre-built template tags generate navigation. In your nav.html template you might have the following:

{% load horizon %}

<div class='nav'>
    {% horizon_main_nav %}

And in your sidebar.html you might have:

{% load horizon %}

<div class='sidebar'>
    {% horizon_dashboard_nav %}

These template tags are aware of the current “active” dashboard and panel via template context variables and will render accordingly.



An application would have the following structure (we’ll use project as an example):

|---dashboard.py <-----Registers the app with Horizon and sets dashboard properties
    |-- images
    |-- __init__.py
    |---panel.py <-----Registers the panel in the app and defines panel properties
    |-- snapshots/
    |-- templates/
    |-- tests.py
    |-- urls.py
    |-- views.py

Dashboard Classes

Inside of dashboard.py you would have a class definition and the registration process:

import horizon

# ObjectStorePanels is an example for a PanelGroup
# for panel classes in general, see below
class ObjectStorePanels(horizon.PanelGroup):
    slug = "object_store"
    name = _("Object Store")
    panels = ('containers',)

class Project(horizon.Dashboard):
    name = _("Project") # Appears in navigation
    slug = "project"    # Appears in URL
    # panels may be strings or refer to classes, such as
    # ObjectStorePanels
    panels = (BasePanels, NetworkPanels, ObjectStorePanels)
    default_panel = 'overview'


Panel Classes

To connect a Panel with a Dashboard class you register it in a panel.py file like so:

import horizon

from openstack_dashboard.dashboards.project import dashboard

class Images(horizon.Panel):
    name = "Images"
    slug = 'images'
    permissions = ('openstack.roles.admin', 'my.openstack.permission',)
    policy_rules = (('endpoint', 'endpoint:rule'),)

# You could also register your panel with another application's dashboard

By default a Panel class looks for a urls.py file in the same directory as panel.py to include in the rollup of url patterns from panels to dashboards to Horizon, resulting in a wholly extensible, configurable URL structure.

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