Fix: configure etc-hosts for overcloud group

Change the etc-hosts role to run on the overcloud group, as using
``ansible_play_hosts_all`` would exclude hosts when running with a
limit.

Also change the gather-facts-delegated role to run on the overcloud
group. The delegated task needs to be included separately as the hostvar
``ansible_host`` cannot be set dynamically based on a loop item in one
task. We loop over the batch indices here so that the tasks are included
in parallel, rather than in series.

Closes-Bug: #2051714

Change-Id: I0465eafa9e4ff37c96064ea8395f0bd461035b40
(cherry picked from commit 498de81)

ansible/roles/etc-hosts/defaults/main.yml

@@ -3,4 +3,4 @@
 customize_etc_hosts: true
 
 # List of hosts to add to /etc/hosts.
-etc_hosts_hosts: "{{ ansible_play_hosts_all }}"
+etc_hosts_hosts: "{{ groups['overcloud'] }}"

ansible/roles/gather-facts-delegated/defaults/main.yml

@@ -1,8 +1,8 @@
 ---
-gather_facts_delegated_limit_hosts: "{{ ansible_play_hosts_all }}"
-gather_facts_delegated_batch_index: "{{ gather_facts_delegated_limit_hosts.index(inventory_hostname) }}"
-gather_facts_delegated_batch_size: "{{ gather_facts_delegated_limit_hosts | length }}"
+gather_facts_delegated_limit_hosts: "{{ groups['overcloud'] }}"
+gather_facts_delegated_batch_index: "{{ ansible_play_batch.index(inventory_hostname) }}"
+gather_facts_delegated_batch_count: "{{ ansible_play_batch | length }}"
 # Use a python list slice to divide the group up.
 # Syntax: [<start index>:<end index>:<step size>]
 gather_facts_delegated_delegate_hosts: >-
-  {{ gather_facts_delegated_limit_hosts[gather_facts_delegated_batch_index | int::gather_facts_delegated_batch_size | int] }}
+  {{ gather_facts_delegated_limit_hosts[gather_facts_delegated_batch_index | int::gather_facts_delegated_batch_count | int] }}

ansible/roles/gather-facts-delegated/tasks/gather-facts-delegated.yml

@@ -0,0 +1,12 @@
+---
+- name: Gather facts for delegated host
+  any_errors_fatal: true
+  setup:
+    filter: "{{ kayobe_ansible_setup_filter }}"
+    gather_subset: "{{ kayobe_ansible_setup_gather_subset }}"
+  delegate_facts: True
+  delegate_to: "{{ delegated_host }}"
+  # NOTE: Without this, the host's ansible_host variable will not be respected
+  # when using delegate_to.
+  vars:
+    ansible_host: "{{ hostvars[delegated_host].ansible_host | default(delegated_host) }}"

ansible/roles/gather-facts-delegated/tasks/main.yml

@@ -1,10 +1,10 @@
 ---
 - name: Gather facts for all hosts (if using --limit)
-  setup:
-    filter: "{{ kayobe_ansible_setup_filter }}"
-    gather_subset: "{{ kayobe_ansible_setup_gather_subset }}"
-  delegate_facts: True
-  delegate_to: "{{ item }}"
-  with_items: "{{ gather_facts_delegated_delegate_hosts }}"
+  include_tasks: gather-facts-delegated.yml
+  vars:
+    delegated_host: "{{ gather_facts_delegated_delegate_hosts[item | int] }}"
+  # Loop over the index into each host's batch, so tasks are not all included serially.
+  with_sequence: start=0 end="{{ gather_facts_delegated_delegate_hosts | length | int - 1 }}"
   when:
-    - not hostvars[item].ansible_facts
+    - item | int < gather_facts_delegated_delegate_hosts | length
+    - not hostvars[gather_facts_delegated_delegate_hosts[item | int]].ansible_facts

releasenotes/notes/fix-etc-hosts-management-6b33748ab37d6273.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Fixes the bug where /etc/hosts was not populated correctly when running
+    Kayobe using a host limit.
+    `LP#2051714 <https://launchpad.net/bugs/2051714>`__