Server Provisioning


School_Navigator is deployed on the following stack.

  • OS: Ubuntu 14.04 LTS
  • Python: 3.4
  • Database: Postgres 9.3
  • Application Server: Gunicorn
  • Frontend Server: Nginx
  • Cache: Memcached

These services can configured to run together on a single machine or on different machines. Supervisord manages the application server process.

Salt Master

Each project needs a Salt Master per environment (staging, production, etc). The master is configured with Fabric. env.master should be set to the IP of this server in the environment where it will be used:

def staging():
    env.master = <ip-of-master>

You will need to be able to connect to the server as a root user. How this is done will depend on where the server is hosted. VPS providers such as Linode will give you a username/password combination. Amazon’s EC2 uses a private key. These credentials will be passed as command line arguments.:

# Template of the command
fab -u <root-user> <environment> setup_master
# Example of provisioning a Linode VM for staging
fab -u root staging setup_master
# Example of provisioning an AWS VM for production
fab -u ubuntu production setup_master -i aws-private.pem

This will install salt-master and update the master configuration file. The master will use a set of base states from checked out at /srv/margarita.

As part of the master setup, a new GPG public/private key pair is generated. The private key remains on the master but the public version is exported and fetched back to the developer’s machine. This will be put in conf/<environment>.pub.gpg. This will be used by all developers to encrypt secrets for the environment and needs to be committed into the repo.

Pillar Setup

Before your project can be deployed to a server, the code needs to be accessible in a git repository. Once that is done you should update conf/pillar/<environment>.sls to set the repo and branch for the environment. E.g., change this:

# FIXME: Update to the correct project repo
  branch: master

to this:

  branch: master

You also need to set project_name and python_version in conf/pillar/project.sls. The project template is set up for 3.4 by default. If you want to use 2.7, you will need to change python_version and make a few changes to requirements. In requirements/production.txt, change python3-memcached to python-memcached.

For the environment you want to setup you will need to set the domain in conf/pillar/<environment>.sls.

You will also need add the developer’s user names and SSH keys to conf/pillar/devs.sls. Each user record (under the parent users: key) should match the format:

   - ssh-rsa <Full SSH Public Key would go here>

Additional developers can be added later, but you will need to create at least one user for yourself.

Managing Secrets

Secret information such as passwords and API keys must be encrypted before being added to the pillar files. As previously noted, provisioning the master for the environment generates a public GPG key which is added to repo under conf/<environment>.pub.gpg To encrypt a new secret using this key, you can use the encrypt fab command:

# Example command
fab <environment> encrypt:<key>=<secret-value>
# Encrypt the SECRET_KEY for the staging environment
fab staging encrypt:SECRET_KEY='thisismysecretkey'

The output of this command will look something like:

  Version: GnuPG v1.4.11 (GNU/Linux)

  -----END PGP MESSAGE-----

where SECRET_KEY would be replace with the key you were trying to encrypt. This block of text should be added to the environment pillar conf/pillar/<environment>.sls under the secrets block:

  "SECRET_KEY": |-
    -----BEGIN PGP MESSAGE-----
    Version: GnuPG v1.4.11 (GNU/Linux)

    -----END PGP MESSAGE-----

The Makefile has a make command for generating a random secret. By default this is 32 characters long but can be adjusted using the length argument.:

make generate-secret
make generate-secret length=64

This can be combined with the above encryption command to generate a random secret and immediately encrypt it.:

fab staging encrypt:SECRET_KEY=`make generate-secret length=64`

By default the project will use the SECRET_KEY if it is set. You can also optionally set a DB_PASSWORD. If not set, you can only connect to the database server on localhost so this will only work for single server setups.

Github Deploy Keys

The repo will also need a deployment key generated so that the Salt minion can access the repository. You can generate a deployment key locally for the new server like so:

# Example command
make <environment>-deploy-key
# Generating the staging deploy key
make staging-deploy-key

This will generate two files named <environment>.priv and conf/<environment>.pub.ssh. The first file contains the private key and the second file contains the public key. The public key needs to be added to the “Deploy keys” in the GitHub repository. For more information, see the Github docs on managing deploy keys:

The text in the private key file should be added to conf/pillar/<environment>.sls` under the label github_deploy_key but it must be encrypted first. To encrypt the file you can use the same encrypt fab command as before passing the filename rather than a key/value pair:

fab staging encrypt:staging.priv

This will create a new file with appends .asc to the end of the original filename (i.e. staging.priv.asc). The entire contents of this file should be added to the github_deploy_key section of the pillar file.:

github_deploy_key: |
  Version: GnuPG v1.4.11 (GNU/Linux)

  -----END PGP MESSAGE-----

Do not commit the original *.priv files into the repo.

Environment Variables

Other environment variables which need to be configured but aren’t secret can be added to the env dictionary in conf/pillar/<environment>.sls without encryption.

# Additional public environment variables to set for the project env:


For instance the default layout expects the cache server to listen at but if there is a dedicated cache server this can be changed via CACHE_HOST. Similarly the DB_HOST/DB_PORT defaults to ''/'':


Setup Checklist

To summarize the steps above, you can use the following checklist

  • repo is set in conf/pillar/<environment>.sls
  • Developer user names and SSH keys have been added to conf/pillar/devs.sls
  • Project name has been set in conf/pillar/project.sls
  • Environment domain name has been set in conf/pillar/<environment>.sls
  • Environment secrets including the deploy key have been set in conf/pillar/<environment>.sls

Provision a Minion

Once you have completed the above steps, you are ready to provision a new server for a given environment. Again you will need to be able to connect to the server as a root user. This is to install the Salt Minion which will connect to the Master to complete the provisioning. To setup a minion you call the Fabric command:

fab <environment> setup_minion:<roles> -H <ip-of-new-server> -u <root-user>
fab staging setup_minion:web,balancer,db-master,cache -H -u root

The available roles are salt-master, web, worker, balancer, db-master, queue and cache. If you are running everything on a single server you need to enable the salt-master, web, balancer, db-master, and cache roles. The worker and queue roles are only needed to run Celery which is explained in more detail later.

Additional roles can be added later to a server via add_role. Note that there is no corresponding delete_role command because deleting a role does not disable the services or remove the configuration files of the deleted role:

fab add_role:web -H

After that you can run the deploy/highstate to provision the new server:

fab <environment> deploy -u <root-user>

The first time you run this command, it may complete before the server is set up. It is most likely still completing in the background. If the server does not become accessible or if you encounter errors during the process, review the Salt logs for any hints in /var/log/salt on the minion and/or master. For more information about deployment, see the server setup </server-setup> documentation.

The initial deployment will create developer users for the server so you should not need to connect as root after the first deploy.

Optional Configuration

The default template contains setup to help manage common configuration needs which are not enabled by default.


The <environment>.sls can also contain a section to enable HTTP basic authentication. This is useful for staging environments where you want to limit who can see the site before it is ready. This will also prevent bots from crawling and indexing the pages. To enable basic auth simply add a section called http_auth in the relevant conf/pillar/<environment>.sls. As with other passwords this should be encrypted before it is added:

# Example encryption
fab <environment> encrypt:<username>=<password>
# Encrypt admin/abc123 for the staging environment
fab staging encrypt:admin=abc123

This would be added in conf/pillar/<environment>.sls under http_auth:

“admin”: |-

—–BEGIN PGP MESSAGE—– Version: GnuPG v1.4.11 (GNU/Linux)

hQEMA87BIemwflZuAQf+J4+G74ZSfrUPRF7z7+DPAmhBlK//A6dvplrsY2RsfEE4 Tfp7QPrHZc5V/gS3FXvlIGWzJOEFscKslzgzlccCHqsNUKE96qqnTNjsIoGOBZ4z tmZV2F3AXzOVv4bOgipKIrjJDQcFJFjZKMAXa4spOAUp4cyIV/AQBu0Gwe9EUkfp yXD+C/qTB0pCdAv5C4vyl+TJ5RE4fGnuPsOqzy4Q0mv+EkXf6EHL1HUywm3UhUaa wbFdS7zUGrdU1BbJNuVAJTVnxAoM+AhNegLK9yAVDweWK6pApz3jN6YKfVLFWg1R +miQe9hxGa2C/9X9+7gxeUagqPeOU3uX7pbUtJldwdJBAY++dkerVIihlbyWOkn4 0HYlzMI27ezJ9WcOV4ywTWwOE2+8dwMXE1bWlMCC9WAl8VkDDYup2FNzmYX87Kl4 9EY= =PrGi —–END PGP MESSAGE—–

This should be a list of key/value pairs. The keys will serve as the usernames and the values will be the password. As with all password usage please pick a strong password.


Many Django projects make use of Celery for handling long running tasks outside of the request/response cycle. Enabling a worker makes use of Django setup for Celery. As documented on that page, you need to create a new file in school_navigator/ and then modify school_navigator/ to import that file. You’ll also need to customize {{ project_name}}/ to import the environment variables from .env. Add this (before the os.environ.setdefault call):

from . import load_env

You should now be able to run the worker locally via (once you’ve added celery to your requirements/base.txt and installed it):

celery -A school_navigator worker

Additionally you will need to uncomment the BROKER_URL setting in the project settings:

# school_navigator/settings/
from .base import *

# ...
BROKER_URL = 'amqp://school_navigator_%(ENVIRONMENT)s:%(BROKER_PASSWORD)s@%(BROKER_HOST)s/school_navigator_%(ENVIRONMENT)s' % os.environ

These are the minimal settings to make Celery work. Refer to the Celery documentation for additional configuration options.

BROKER_HOST defaults to If the queue server is configured on a separate host that will need to be reflected in the BROKER_URL setting. This is done by setting the BROKER_HOST environment variable in the env dictionary of conf/pillar/<environment>.sls.

To add the states you should add the worker role when provisioning the minion. At least one server in the stack should be provisioned with the queue role as well. This will use RabbitMQ as the broker by default. The RabbitMQ user will be named school_navigator_<environment> and the vhost will be named school_navigator_<environment> for each environment. It requires that you add a password for the RabbitMQ user to each of the conf/pillar/<environment>.sls under the secrets using the key BROKER_PASSWORD. As with all secrets this must be encrypted.

The worker will run also run the beat process which allows for running periodic tasks.


The default configuration expects the site to run under HTTPS everywhere. However, unless an SSL certificate is provided, the site will use a self-signed certificate. To include a certificate signed by a CA you must update the ssl_key and ssl_cert pillars in the environment secrets. The ssl_cert should contain the intermediate certificates provided by the CA. It is recommended that this pillar is only pushed to servers using the balancer role. See the secrets.ex file for an example.

You can use the below OpenSSL commands to generate the key and signing request:

# Generate a new 2048 bit RSA key
openssl genrsa -out school_navigator.key 2048
# Make copy of the key with the passphrase
cp school_navigator.key
# Remove any passphrase
openssl rsa -in -out school_navigator.key
# Generate signing request
openssl req -nodes -sha256 -new -key school_navigator.key -out school_navigator.csr

The last command will prompt you for information for the signing request including the organization for which the request is being made, the location (country, city, state), email, etc. The most important field in this request is the common name which must match the domain for which the certificate is going to be deployed (i.e

This signing request (.csr) will be handed off to a trusted Certificate Authority (CA) such as StartSSL, NameCheap, GoDaddy, etc. to purchase the signed certificate. The contents of the *.key file will be added to the ssl_key pillar and the signed certificate from the CA will be added to the ssl_cert pillar. These should be encrypted using the same proceedure as with the private SSH deploy key.



fab -u ubuntu production setup_master -i ~/.ssh/aws-cfa.pem
rm production*.asc

fab production encrypt:DB_PASSWORD=`make generate-secret`
fab production encrypt:SECRET_KEY=`make generate-secret length=64`
fab production encrypt:BROKER_PASSWORD=`make generate-secret`
fab production encrypt:NEW_RELIC_LICENSE_KEY='<fill-me-in>'
fab production encrypt:production-ssl.key && cat production-ssl.key.asc
fab production encrypt:production-ssl.cert && cat production-ssl.cert.asc

fab production setup_minion:salt-master,web,balancer,db-master,cache,queue,worker -H -u ubuntu -i ~/.ssh/aws-cfa.pem
fab production deploy -H -u ubuntu -i ~/.ssh/aws-cfa.pem
fab production deploy

# load db dump (run on server)
sudo supervisorctl stop all
sudo -u postgres dropdb school_navigator_production
sudo -u postgres createdb -E UTF-8 -O school_navigator_production school_navigator_production
sudo -u postgres psql -c 'CREATE EXTENSION postgis;' school_navigator_production
sudo -u postgres pg_restore -Ox -Ft --no-data-for-failed-tables -U school_navigator_production -d school_navigator_production school_navigator_production.tar
sudo supervisorctl start all