Merge "Fix fact gathering with --limit"

ansible/gather-facts.yml

+---
+# NOTE(awiddersheim): Gather facts for all hosts as a
+# first step since several plays below require them when
+# building their configurations. The below 'gather_facts'
+# set to 'false' is a bit confusing but this is to avoid
+# Ansible gathering facts twice.
+- name: Gather facts for all hosts
+  hosts: all
+  serial: '{{ kolla_serial|default("0") }}'
+  gather_facts: false
+  tasks:
+    - name: Gather facts
+      setup:
+
+    - name: Group hosts to determine when using --limit
+      group_by:
+        key: "all_using_limit_{{ (ansible_play_batch | length) != (groups['all'] | length) }}"
+  tags: always
+
+# NOTE(pbourke): This case covers deploying subsets of hosts using --limit. The
+# limit arg will cause the first play to gather facts only about that node,
+# meaning facts such as IP addresses for rabbitmq nodes etc. will be undefined
+# in the case of adding a single compute node.
+# NOTE(mgoddard): Divide all hosts to be queried between the hosts selected via
+# the limit.
+- name: Gather facts for all hosts (if using --limit)
+  hosts: all_using_limit_True
+  serial: '{{ kolla_serial|default("0") }}'
+  gather_facts: false
+  vars:
+    batch_index: "{{ ansible_play_batch.index(inventory_hostname) }}"
+    batch_size: "{{ ansible_play_batch | length }}"
+    # Use a python list slice to divide the group up.
+    # Syntax: [<start index>:<end index>:<step size>]
+    delegate_hosts: "{{ groups['all'][batch_index | int::batch_size | int] }}"
+  tasks:
+    - name: Gather facts
+      setup:
+      delegate_facts: True
+      delegate_to: "{{ item }}"
+      with_items: "{{ delegate_hosts }}"
+      # We gathered facts for all hosts in the batch during the first play.
+      when: item not in ansible_play_batch
+  tags: always

ansible/kolla-host.yml

 ---
-# NOTE(awiddersheim): Gather facts for all hosts as a
-# first step since several plays below require them when
-# building their configurations. The below 'gather_facts'
-# set to 'false' is a bit confusing but this is to avoid
-# Ansible gathering facts twice.
-- name: Gather facts for all hosts
-  hosts: all
-  serial: '{{ kolla_serial|default("0") }}'
-  gather_facts: false
-  tasks:
-    - setup:
-  tags: always
-
-# NOTE(pbourke): This case covers deploying subsets of hosts using --limit. The
-# limit arg will cause the first play to gather facts only about that node,
-# meaning facts such as IP addresses for rabbitmq nodes etc. will be undefined
-# in the case of adding a single compute node.
-# We don't want to add the delegate parameters to the above play as it will
-# result in ((num_nodes-1)^2) number of SSHs when running for all nodes
-# which can be very inefficient.
-- name: Gather facts for all hosts (if using --limit)
-  hosts: all
-  serial: '{{ kolla_serial|default("0") }}'
-  gather_facts: false
-  tasks:
-    - setup:
-      delegate_facts: True
-      delegate_to: "{{ item }}"
-      with_items: "{{ groups['all'] }}"
-      when:
-        - (ansible_play_batch | length) != (groups['all'] | length)
+- import_playbook: gather-facts.yml
 
 - name: Apply role baremetal
   hosts: baremetal

ansible/site.yml

 ---
-# NOTE(awiddersheim): Gather facts for all hosts as a
-# first step since several plays below require them when
-# building their configurations. The below 'gather_facts'
-# set to 'false' is a bit confusing but this is to avoid
-# Ansible gathering facts twice.
-- name: Gather facts for all hosts
-  hosts: all
-  serial: '{{ kolla_serial|default("0") }}'
-  gather_facts: false
-  tasks:
-    - setup:
-  tags: always
-
-# NOTE(pbourke): This case covers deploying subsets of hosts using --limit. The
-# limit arg will cause the first play to gather facts only about that node,
-# meaning facts such as IP addresses for rabbitmq nodes etc. will be undefined
-# in the case of adding a single compute node.
-# We don't want to add the delegate parameters to the above play as it will
-# result in ((num_nodes-1)^2) number of SSHs when running for all nodes
-# which can be very inefficient.
-- name: Gather facts for all hosts (if using --limit)
-  hosts: all
-  serial: '{{ kolla_serial|default("0") }}'
-  gather_facts: false
-  tasks:
-    - setup:
-      delegate_facts: True
-      delegate_to: "{{ item }}"
-      with_items: "{{ groups['all'] }}"
-      when:
-        - (ansible_play_batch | length) != (groups['all'] | length)
-  tags: always
+- import_playbook: gather-facts.yml
 
 # NOTE(mgoddard): In large environments, even tasks that are skipped can take a
 # significant amount of time. This is an optimisation to prevent any tasks