DevStack is a tool used to quickly deploy OpenStack from source code for development and testing purposes. Plugins allow custom OpenStack services to be integrated with DevStack. A plugin contains scripts that are executed at different points during deployment to install and configure the custom service. Functions are provided to help with common tasks like installing packages or configuring services.

1. How to integrate custom OpenStack services with
DevStack
Sławek Kapłoński
slawomir.kaplonski@corp.ovh.com
IRC: slaweq @ freenode

2. Agenda
• What is DevStack
• DevStack config
• Scripts in DevStack
• DevStack plugin
• What is it?
• How to do own plugin?

3. https://docs.openstack.org/developer/devstack/
DevStack is a series of extensible scripts used to
quickly bring up a complete OpenStack environment
based on the latest versions of everything from git
master. It is used interactively as a development
environment and as the basis for much of the
OpenStack project’s functional testing.

4. DevStack alternatives
• Packstack - written in Python, uses Puppet modules, works
over SSH, supports CentOS and RHEL
• OpenStack-ansible - can deploy Openstack from Git
repositories, from newest branch, services runs in LXC
containers,
• OpenStack Kolla - provides containers and deployment
tools for OpenStack,
• TripleO - allows to install, upgrade and operate OpenStack
cloud, using Puppet underneath

5. Supported operating systems
✓ Ubuntu 16.04 or newer
✓ Fedora F24 or newer
✓ CentOS/RHEL 7 or newer
✓ Other platforms - it may work but is not
supported by community

6. Configuration of DevStack
✓ Environment variables
[[local|localrc]]
ADMIN_PASSWORD=secret
export DATABASE_PASSWORD=super_secret_db_password
DATABASE_PASSWORD=super_secret_db_password ./stack.sh
✓ In command line
✓ Persistent variables can be stored in
local.conf

7. Basic scripts in DevStack
stack.sh
Installs and configures various OpenStack and
additional, required by OpenStack, services
like MySQL or RabbitMQ.

8. Basic scripts in DevStack
unstack.sh
Stops OpenStack services which were started by
stack.sh
Services like MySQL or RabbitMQ are not
stopped

9. Basic scripts in DevStack
clean.sh
Do the same as unstack.sh but also:
• tries to clean config files of OpenStack services,
• stops RabbitMQ and MySQL,
• cleans other services.

10. DevStack - OpenStack projects
Supported
✓ Nova ✓ Neutron
✓ Glance ✓ Cinder
✓ Keystone ✓ Horizon
✓ Swift ✓ Heat
Not supported
- Ironic
- Magnum
- Freezer
- Watcher
- Kuryr
- Trove
- Many others
✓ Tempest

11. DevStack Plugins

12. Why to do Your own DevStack plugin?
• Simplification of installation Your OpenStack
extension for further testing and develop
• Install DevStack with some specific
packages, configurations, etc.
• Test own OpenStack project in gate on
OpenStack CI infrastructure

13. DevStack plugin
• can be in any external git repository that
contains devstack/ directory,
• are written in bash,
• list of existing plugins on https://docs.openstack.org/
developer/devstack/plugin-registry.html

14. DevStack plugin
devstack/ directory can contains 3 files:
• plugin.sh - plugin script executed by DevStack
• settings - file with global variables - config options
for Your plugin
• override-defaults - file with overwritten DevStack’s
global variables

15. DevStack plugin - settings file
ubuntu@devstack-dev:~/networking-ovh$ cat devstack/settings
# Interface used by ovs agent to talk with openvswitch
OF_INTERFACE=${OF_INTERFACE:-"ovs-ofctl"}
VRACK_DUMMY_SERVER_IP=${VRACK_DUMMY_SERVER_IP:-"127.0.0.1"}
VRACK_DUMMY_SERVER_PORT=${VRACK_DUMMY_SERVER_PORT:-1234}
enable_service vrack_dummy

16. DevStack plugin - override-defaults file
ubuntu@devstack-dev:~/networking-ovh$ cat devstack/override-defaults
NEUTRON_CORE_PLUGIN=${NEUTRON_CORE_PLUGIN:-ovh_ml2}
Q_AGENT=${Q_AGENT:-openvswitch-multi}
Q_SERVICE_PLUGIN_CLASSES=${Q_SERVICE_PLUGIN_CLASSES:-"vrack,ipalias,qos"}

17. DevStack plugin - plugin.sh structure
Script called in specific points during stack.sh,
unstack.sh and clean.sh
source $PATH/TO/plugin.sh <mode> [phase]
This script is called by devstack in following
way

18. DevStack plugin - plugin.sh phase
• pre-install - Called after system (OS) setup is complete and
before project source is installed
• install - Called after the layer 1 and 2 projects source and
their dependencies have been installed.
• post-config - Called after the layer 1 and 2 services have
been configured. All configuration files for enabled services
should exist at this point.

19. DevStack plugin - plugin.sh phase
• extra - Called near the end after layer 1 and 2 services have
been started.
• test-config - Called at the end of DevStack used to
configure tempest or any other test environments

20. DevStack - enable plugin
[[local|localrc]]
enable_plugin <NAME> <GITURL> [GITREF]
Plugin is registered by adding following line in
local.conf file
enable_plugin ec2-api git://git.openstack.org/openstack/ec2-api

21. DevStack plugin - useful functions
install_package <PACKAGE_NAME> [PACKAGE_NAME …]
Packages installation
setup_develop <PROJECT_DIR> [EXTRAS]
Python projects installation
setup_install <PROJECT_DIR> [EXTRAS]

22. DevStack plugin - useful functions
uninstall_package <PACKAGE_NAME> [PACKAGE_NAME …]
Packages deinstallation
Running process
run_process <SERVICE_NAME> <COMMAND> [GROUP] [USER]

23. DevStack plugin - useful functions
iniset <FILE> <SECTION> <OPTION> <VALUE>
Set config option
iniset_multiline <FILE> <SECTION> <OPTION> <VALUE>

24. DevStack plugin - useful functions
For more functions check devstack code. For example:
• devstack/functions-common
• devstack/inc/python
• devstack/inc/ini-config
• and others…

25. Thank you
How to integrate custom OpenStack services with DevStack
Sławek Kapłoński
slawomir.kaplonski@corp.ovh.com
IRC: slaweq @ freenode
@slaweq