Use more permissive regex to remove the offending 127.0.1.1

line from /etc/hosts

Ubuntu always uses 127.0.1.1 for that with some tricky sauce
around `hostname` depending on whether it contains '.' or not.
And when I mean `hostname` it's the one returned by `hostname`
command with no arguments.

ansible_hostname is always a single word so we can match on that.

I did not want to remove just any 127.0.1.1 in case someone
is using it for other purposes. :-)

Change-Id: I8bd3d42a5e3bd0f63336ed60a0af90d52b1650d6
Closes-bug: #1862739

ansible/roles/baremetal/tasks/pre-install.yml

@@ -8,14 +8,16 @@
   become: True
   when: customize_etc_hosts | bool
 
-# NOTE(mgoddard): Ubuntu includes a line in /etc/hosts that makes the local
-# hostname and nodename (if different) point to 127.0.1.1. This can break
+# NOTE(mgoddard): Ubuntu may include a line in /etc/hosts that makes the local
+# hostname and fqdn point to 127.0.1.1. This can break
 # RabbitMQ, which expects the hostname to resolve to the API network address.
-# Remove these troublesome entries.
-- name: Ensure hostname does not point to loopback in /etc/hosts
+# Remove the troublesome entry.
+# see https://bugs.launchpad.net/kolla-ansible/+bug/1837699
+# and https://bugs.launchpad.net/kolla-ansible/+bug/1862739
+- name: Ensure hostname does not point to 127.0.1.1 in /etc/hosts
   lineinfile:
     dest: /etc/hosts
-    regexp: "^127.\\d+.\\d+.\\d+(\\s+{{ ansible_nodename }})?\\s+{{ ansible_hostname }}$"
+    regexp: "^127.0.1.1\\b.*\\s{{ ansible_hostname }}\\b"
     state: absent
   become: True
   when: customize_etc_hosts | bool

releasenotes/notes/bug-1862739-05246e7599375800.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    Use more permissive regex to remove the offending 127.0.1.1 line
+    from /etc/hosts.
+    `LP#1862739
+    <https://bugs.launchpad.net/kolla-ansible/+bug/1862739>`__