Merge pull request #2474 from mirwan/localhost_in_etc_hosts

Localhost in hosts files should be updated (if necessary), not overriden

roles/kubernetes/preinstall/defaults/main.yml

@@ -33,3 +33,16 @@ populate_inventory_to_hosts_file: true
 preinstall_selinux_state: permissive
 
 sysctl_file_path: "/etc/sysctl.d/99-sysctl.conf"
+
+etc_hosts_localhost_entries:
+  127.0.0.1:
+    expected:
+      - localhost
+      - localhost.localdomain
+  ::1:
+    expected:
+      - localhost6
+      - localhost6.localdomain
+    unexpected:
+      - localhost
+      - localhost.localdomain

roles/kubernetes/preinstall/tasks/etchosts.yml

@@ -22,18 +22,33 @@
     - loadbalancer_apiserver is defined
     - loadbalancer_apiserver.address is defined
 
-- name: Hosts | localhost ipv4 in hosts file
-  lineinfile:
-    dest: /etc/hosts
-    line: "127.0.0.1 localhost localhost.localdomain"
-    regexp: '^127.0.0.1.*$'
-    state: present
-    backup: yes
+- name: Hosts | Retrieve hosts file content
+  slurp:
+    src: /etc/hosts
+  register: etc_hosts_content
 
-- name: Hosts | localhost ipv6 in hosts file
+- name: Hosts | Extract existing entries for localhost from hosts file
+  set_fact:
+    etc_hosts_localhosts_dict: >-
+       {%- set splitted = (item | regex_replace('[ ]+', ' ')|regex_replace('#.+$')|trim).split( ' ') -%}
+       {{ etc_hosts_localhosts_dict|default({}) | combine({splitted[0]: splitted[1::] }) }}
+  with_items: "{{ (etc_hosts_content['content'] | b64decode).split('\n') }}"
+  when:
+    - etc_hosts_content.content is defined
+    - etc_hosts_localhost_entries.keys()|map('regex_replace', '(.*)', '^\\1 .*') | map('match', item) | list | length > 0
+
+- name: Hosts | Update target hosts file entries dict with required entries
+  set_fact:
+    etc_hosts_localhosts_dict_target: >-
+      {%- set target_entries = etc_hosts_localhosts_dict.get(item.key, []) | difference(item.value.get('unexpected' ,[])) -%}
+      {{ etc_hosts_localhosts_dict_target|default({}) | combine({item.key: (target_entries + item.value.expected)|unique}) }}
+  with_dict: "{{ etc_hosts_localhost_entries }}"
+
+- name: Hosts | Update (if necessary) hosts file
   lineinfile:
     dest: /etc/hosts
-    line: "::1 localhost6 localhost6.localdomain"
-    regexp: '^::1.*$'
+    line: "{{ item.key }} {{ item.value|join(' ') }}"
+    regexp: "^{{ item.key }}.*$"
     state: present
     backup: yes
+  with_dict: "{{ etc_hosts_localhosts_dict_target }}"