kayobe/releasenotes/notes/setup-module-args-2c36e56bf78ab5f0.yaml
Mark Goddard 2648f48746 Make setup module arguments configurable
Ansible facts can have a large impact on the performance of the Ansible
control host. This patch introduces some control over which facts are
gathered (kayobe_ansible_setup_gather_subset) and which facts are stored
(kayobe_ansible_setup_filter). By default we do not change the default
values of these arguments to the setup module. The flexibility of these
arguments is limited, but they do provide enough for a large performance
improvement in a typical moderate to large OpenStack cloud.

In particular, the large complex dict fact for each interface has a
large effect, and on an OpenStack controller or hypervisor there may be
many virtual interfaces. We can use the kayobe_ansible_setup_filter
variable to help:

    kayobe_ansible_setup_filter: 'ansible_[!qt]*'

This causes Ansible to collect but not store facts matching that
pattern, which includes the virtual interface facts. Currently we are
not referencing other facts matching the pattern within Kayobe.
Note that including the 'ansible_' prefix causes meta facts module_setup
and gather_subset to be filtered, but this seems to be the only way to
get a good match on the interface facts. To work around this, we use
ansible_facts rather than module_setup to detect whether facts exist in
the cache.

The exact improvement will vary, but has been reported to be as large as
18x on systems with many virtual interfaces.

This change also introduces a new command to gather facts for Kayobe &
Kolla Ansible on demand, 'kayobe overcloud facts gather'. This can be
used to populate a fact cache.

Depends-On: https://review.opendev.org/c/openstack/kolla-ansible/+/794610
Story: 2007993
Task: 42586

Change-Id: I5ce3c734433e1682ee942867505468c57440e689
2021-09-27 09:31:09 +00:00

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YAML

---
features:
- |
Adds support for configuring the ``filter`` and ``gather_subset`` arguments
for the ``setup`` module via ``kayobe_ansible_setup_filter`` and
``kayobe_ansible_setup_gather_subset`` respectively. These can be used to
reduce the number of facts, which can have a significant effect on
performance of Ansible.
- |
Adds a new command, ``kayobe overcloud facts gather``, to gather Ansible
facts for overcloud hosts. This may be useful for populating a fact cache.