Deckhand

Deckhand is a storage service for YAML-based configuration documents, which are managed through version control and automatically validated. Deckhand provides users with a variety of different document types that describe complex configurations using the features listed below.

Core Responsibilities

• layering - helps reduce duplication in configuration while maintaining auditability across many sites
• substitution - provides separation between secret data and other configuration data, while allowing a simple interface for clients
• revision history - improves auditability and enables services to provide functional validation of a well-defined collection of documents that are meant to operate together
• validation - allows services to implement and register different kinds of validations and report errors

Getting Started

Pre-requisites

• tox

  To install tox run:

  $ sudo apt-get install tox

• PostgreSQL

  Deckhand only supports PostgreSQL. Install it by running:

  $ sudo apt-get update
  $ sudo apt-get install postgresql postgresql-contrib

Quick Start

Docker can be used to quickly instantiate the Deckhand image. After installing Docker, create a basic configuration file:

$ tox -e genconfig

Resulting deckhand.conf.sample file is output to :path:etc/deckhand/deckhand.conf.sample

Move the sample configuration file into a desired directory (i.e. $CONF_DIR).

At a minimum the [database].connection config option must be set. Provide it with a PostgreSQL database connection. Or to conveniently create an ephemeral PostgreSQL DB run:

$ eval `pifpaf run postgresql`

Substitute the connection information (which can be retrieved by running export | grep PIFPAF_POSTGRESQL_URL) into the config file inside etc/deckhand/deckhand.conf.sample:

.. code-block:: ini

[database]

# # From oslo.db #

# The SQLAlchemy connection string to use to connect to the database. # (string value) connection = postgresql://localhost/postgres?host=/tmp/tmpsg6tn3l9&port=9824

Finally, run Deckhand:

$ [sudo] docker run --rm \
    --net=host \
    -p 9000:9000 \
    -v $CONF_DIR:/etc/deckhand
    quay.io/attcomdev/deckhand:latest

To kill the ephemeral DB afterward:

$ pifpaf_stop

Manual Installation

Note

The commands below assume that they are being executed from the root Deckhand directory.

Install dependencies needed to spin up Deckhand via uwsgi:

$ sudo pip install uwsgi
$ virtualenv -p python3 /var/tmp/deckhand
$ . /var/tmp/deckhand/bin/activate
$ pip install -r requirements.txt test-requirements.txt
$ python setup.py install

Afterward, create a sample configuration file automatically:

$ tox -e genconfig

Resulting deckhand.conf.sample file is output to :path:etc/deckhand/deckhand.conf.sample

Create the directory /etc/deckhand and copy the config file there:

$ [sudo] cp etc/deckhand/deckhand.conf.sample /etc/deckhand/deckhand.conf

To specify an alternative directory for the config file, run:

$ export OS_DECKHAND_CONFIG_DIR=<PATH>
$ [sudo] cp etc/deckhand/deckhand.conf.sample ${OS_DECKHAND_CONFIG_DIR}/deckhand.conf

To conveniently create an ephemeral PostgreSQL DB run:

$ eval `pifpaf run postgresql`

Retrieve the environment variable which contains connection information:

$ export | grep PIFPAF_POSTGRESQL_URL
declare -x PIFPAF_POSTGRESQL_URL="postgresql://localhost/postgres?host=/tmp/tmpsg6tn3l9&port=9824"

Substitute the connection information into the config file in ${OS_DECKHAND_CONFIG_DIR}:

.. code-block:: ini

[database]

# # From oslo.db #

# The SQLAlchemy connection string to use to connect to the database. # (string value) connection = postgresql://localhost/postgres?host=/tmp/tmpsg6tn3l9&port=9824

Finally, run Deckhand:

$ uwsgi --ini wsgi.ini

To kill the ephemeral DB afterward:

$ pifpaf_stop

Testing

Automated Testing

To run unit tests using sqlite, execute:

$ tox -epy27
$ tox -epy35

against a py27- or py35-backed environment, respectively. To run individual unit tests, run:

$ tox -e py27 -- deckhand.tests.unit.db.test_revisions

for example.

To run functional tests:

$ tox -e functional

You can also run a subset of tests via a regex:

$ tox -e functional -- gabbi.suitemaker.test_gabbi_document-crud-success-multi-bucket

Intgration Points

Deckhand has the following integration points:

• Keystone (OpenStack Identity service) provides authentication and support for role based authorization.
• PostgreSQL is used to persist information to correlate workflows with users and history of workflow commands.

Note

Currently, other database backends are not supported.

Though, being a low-level service, has many other UCP services that integrate with it, including:

• Drydock is orchestrated by Shipyard to perform bare metal node provisioning.
• Promenade is indirectly orchestrated by Shipyard to configure and join Kubernetes nodes.
• Armada is orchestrated by Shipyard to deploy and test Kubernetes workloads.

Further Reading

Undercloud Platform (UCP).