Merge "Make setup module arguments configurable"

ansible/gather-facts.yml

@@ -5,8 +5,15 @@
 - name: Gather facts for all hosts
   hosts: all
   serial: '{{ kolla_serial|default("0") }}'
-  gather_facts: true
+  gather_facts: false
   tasks:
+    - name: Gather facts
+      setup:
+        filter: "{{ kolla_ansible_setup_filter }}"
+        gather_subset: "{{ kolla_ansible_setup_gather_subset }}"
+      when:
+        - not ansible_facts
+
     - name: Group hosts to determine when using --limit
       group_by:
         key: "all_using_limit_{{ (ansible_play_batch | length) != (groups['all'] | length) }}"
@@ -32,10 +39,12 @@
   tasks:
     - name: Gather facts
       setup:
+        filter: "{{ kolla_ansible_setup_filter }}"
+        gather_subset: "{{ kolla_ansible_setup_gather_subset }}"
       delegate_facts: True
       delegate_to: "{{ item }}"
       with_items: "{{ delegate_hosts }}"
       # We gathered facts for all hosts in the batch during the first play.
       when:
-        - not hostvars[item].ansible_facts.module_setup | default(false)
+        - not hostvars[item].ansible_facts
   tags: always

ansible/group_vars/all.yml

@@ -20,6 +20,21 @@ node_config_directory: "/etc/kolla"
 config_owner_user: "root"
 config_owner_group: "root"
 
+###################
+# Ansible options
+###################
+
+# This variable is used as the "filter" argument for the setup module.  For
+# instance, if one wants to remove/ignore all Neutron interface facts:
+# kolla_ansible_setup_filter: "ansible_[!qt]*"
+# By default, we do not provide a filter.
+kolla_ansible_setup_filter: "{{ omit }}"
+
+# This variable is used as the "gather_subset" argument for the setup module.
+# For instance, if one wants to avoid collecting facts via facter:
+# kolla_ansible_setup_gather_subset: "all,!facter"
+# By default, we do not provide a gather subset.
+kolla_ansible_setup_gather_subset: "{{ omit }}"
 
 ###################
 # Kolla options

doc/source/user/ansible-tuning.rst

@@ -83,3 +83,40 @@ disable fact variable injection.
 
    [defaults]
    inject_facts_as_vars = False
+
+Fact filtering
+--------------
+
+Ansible facts filtering can be used to speed up Ansible.  Environments with
+many network interfaces on the network and compute nodes can experience very
+slow processing with Kolla Ansible. This happens due to the processing of the
+large per-interface facts with each task.  To avoid storing certain facts, we
+can use the ``kolla_ansible_setup_filter`` variable, which is used as the
+``filter`` argument to the ``setup`` module. For example, to avoid collecting
+facts for virtual interfaces beginning with q or t:
+
+.. code-block:: yaml
+
+   kolla_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 Kolla Ansible.  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.
+
+The exact improvement will vary, but has been reported to be as large as 18x on
+systems with many virtual interfaces.
+
+Fact gathering subsets
+----------------------
+
+It is also possible to configure which subsets of facts are gathered, via
+``kolla_ansible_setup_gather_subset``, which is used as the ``gather_subset``
+argument to the ``setup`` module. For example, if one wants to avoid collecting
+facts via facter:
+
+.. code-block:: yaml
+
+   kolla_ansible_setup_gather_subset: "all,!facter"

etc/kolla/globals.yml

@@ -5,6 +5,22 @@
 # commented parameters are shown here, To override the default value uncomment
 # the parameter and change its value.
 
+###################
+# Ansible options
+###################
+
+# This variable is used as the "filter" argument for the setup module.  For
+# instance, if one wants to remove/ignore all Neutron interface facts:
+# kolla_ansible_setup_filter: "ansible_[!qt]*"
+# By default, we do not provide a filter.
+#kolla_ansible_setup_filter: "{{ omit }}"
+
+# This variable is used as the "gather_subset" argument for the setup module.
+# For instance, if one wants to avoid collecting facts via facter:
+# kolla_ansible_setup_gather_subset: "all,!facter"
+# By default, we do not provide a gather subset.
+#kolla_ansible_setup_gather_subset: "{{ omit }}"
+
 ###############
 # Kolla options
 ###############

releasenotes/notes/setup-module-args-c29e1815bbbe8aca.yaml

+---
+features:
+  - |
+    Adds support for configuring the ``filter`` and ``gather_subset`` arguments
+    for the ``setup`` module via ``kolla_ansible_setup_filter`` and
+    ``kolla_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.