04fd12b945
Created the admin directory, remove some files from user dir and placed into admin and contributor. For more detail, see the doc migration spec. http://specs.openstack.org/openstack/docs-specs/specs/pike/os-manuals-migration.html Change-Id: I84c565d7d14a4d90270a53e14ab93a10f7ffb9b7 Partially-Implements: blueprint ka-queens-doc-restructure
77 lines
3.9 KiB
ReStructuredText
77 lines
3.9 KiB
ReStructuredText
.. _deployment-philosophy:
|
|
|
|
=============================
|
|
Kolla's Deployment Philosophy
|
|
=============================
|
|
|
|
Overview
|
|
========
|
|
|
|
Kolla has an objective to replace the inflexible, painful, resource-intensive
|
|
deployment process of OpenStack with a flexible, painless, inexpensive
|
|
deployment process. Often to deploy OpenStack at the 100+ nodes scale, small
|
|
businesses may require building a team of OpenStack professionals to
|
|
maintain and manage the OpenStack deployment. Finding people experienced in
|
|
OpenStack deployment is very difficult and expensive, resulting in a big
|
|
barrier for OpenStack adoption. Kolla seeks to remedy this set of problems by
|
|
simplifying the deployment process while enabling flexible deployment models.
|
|
|
|
Kolla is a highly opinionated deployment tool out of the box. This permits
|
|
Kolla to be deployable with the simple configuration of three key/value pairs.
|
|
As an operator's experience with OpenStack grows and the desire to customize
|
|
OpenStack services increases, Kolla offers full capability to override every
|
|
OpenStack service configuration option in the deployment.
|
|
|
|
Why not Template Customization?
|
|
===============================
|
|
|
|
The Kolla upstream community does not want to place key/value pairs in the
|
|
Ansible playbook configuration options that are not essential to obtaining
|
|
a functional deployment. If the Kolla upstream starts down the path of
|
|
templating configuration options, the Ansible configuration could conceivably
|
|
grow to hundreds of configuration key/value pairs which is unmanageable.
|
|
Further, as new versions of Kolla are released, there would be independent
|
|
customization available for different versions creating an unsupportable and
|
|
difficult to document environment. Finally, adding key/value pairs for
|
|
configuration options creates a situation in which development and release
|
|
cycles are required in order to successfully add new customizations.
|
|
Essentially templating in configuration options is not a scalable solution
|
|
and would result in an inability of the project to execute its mission.
|
|
|
|
Kolla's Solution to Customization
|
|
=================================
|
|
|
|
Rather than deal with the customization madness of templating configuration
|
|
options in Kolla's Ansible playbooks, Kolla eliminates all the inefficiencies
|
|
of existing deployment tools through a simple, tidy design: custom
|
|
configuration sections.
|
|
|
|
During deployment of an OpenStack service, a basic set of default configuration
|
|
options are merged with and overridden by custom ini configuration sections.
|
|
Kolla deployment customization is that simple! This does create a situation
|
|
in which the Operator must reference the upstream documentation if a
|
|
customization is desired in the OpenStack deployment. Fortunately the
|
|
configuration options documentation is extremely mature and well-formulated.
|
|
|
|
As an example, consider running Kolla in a virtual machine. In order to
|
|
launch virtual machines from Nova in a virtual environment, it is necessary
|
|
to use the QEMU hypervisor, rather than the KVM hypervisor. To achieve this
|
|
result, simply `mkdir -p /etc/kolla/config` and modify the file
|
|
`/etc/kolla/config/nova.conf` with the contents::
|
|
|
|
[libvirt]
|
|
virt_type=qemu
|
|
|
|
After this change Kolla will use an emulated hypervisor with lower performance.
|
|
Kolla could have templated this commonly modified configuration option. If
|
|
Kolla starts down this path, the Kolla project could end with hundreds of
|
|
config options all of which would have to be subjectively evaluated for
|
|
inclusion or exclusion in the source tree.
|
|
|
|
Kolla's approach yields a solution which enables complete customization without
|
|
any upstream maintenance burden. Operators don't have to rely on a subjective
|
|
approval process for configuration options nor rely on a
|
|
development/test/release cycle to obtain a desired customization. Instead
|
|
operators have ultimate freedom to make desired deployment choices immediately
|
|
without the approval of a third party.
|