Adding a new service¶
When adding a role for a new service in Ansible, there are couple of patterns which Kolla uses throughout and which should be followed.
The sample inventories
Entries should be added for the service in each of
ansible/inventory/multinode
andansible/inventory/all-in-one
.The playbook
The main playbook that ties all roles together is in
ansible/site.yml
, this should be updated with appropriate roles, tags, and conditions. Ensure also that supporting hosts such as haproxy are updated when necessary.The common role
A
common
role exists which sets up logging,kolla-toolbox
and other supporting components. This should be included in all services withinmeta/main.yml
of your role.Common tasks
All services should include the following tasks:
deploy.yml
: Used to bootstrap, configure and deploy containers for the service.reconfigure.yml
: Used to push new configuration files to the host and restart the service.pull.yml
: Used to pre fetch the image into the Docker image cache on hosts, to speed up initial deploys.upgrade.yml
: Used for upgrading the service in a rolling fashion. May include service specific setup and steps as not all services can be upgraded in the same way.
Log rotation
For OpenStack services there should be a
cron-logrotate-PROJECT.conf.j2
template file inansible/roles/common/templates
with the following content:"/var/log/kolla/PROJECT/*.log" { }
For OpenStack services there should be an entry in the
services
list in thecron.json.j2
template file inansible/roles/common/templates
.
Log delivery
For OpenStack services the service should add a new
rewriterule
in thematch
element in the01-rewrite.conf.j2
template file inansible/roles/common/templates/conf/filter
to deliver log messages to Elasticsearch.
Documentation
For OpenStack services there should be an entry in the list
OpenStack services
in theREADME.rst
file.For infrastructure services there should be an entry in the list
Infrastructure components
in theREADME.rst
file.
Syntax
All YAML data files should start with three dashes (
---
).
Other than the above, most service roles abide by the following pattern:
Register
: Involves registering the service with Keystone, creating endpoints, roles, users, etc.Config
: Distributes the config files to the nodes to be pulled into the container on startup.Bootstrap
: Creating the database (but not tables), database user for the service, permissions, etc.Bootstrap Service
: Starts a one shot container on the host to create the database tables, and other initial run time config.
Ansible handlers are used to create or restart containers when necessary.