Handle FIXME about the hosts file

An even better fix is to make the inventory better structured so moving
these hosts is easier. The other proper fix is to make playbooks more
idempotent so rerunning is not a problem but thats technical debt for
now.

Author: vmcj

provision-contest/ansible/hosts

@@ -2,6 +2,9 @@
 ansible_user=root
 ansible_python_interpreter=/usr/bin/python3
 
+# When moving clients for ad-hoc actions:
+# move them to their own group to keep hosts files on deployed machines in sync.
+
 [domserver]
 domjudge-primary     ansible_host=10.3.3.216 KEEPALIVED_PRIORITY=100 EFI_ORDER='0\,1\,3\,4'
 domjudge-backup      ansible_host=10.3.3.217 KEEPALIVED_PRIORITY=99 EFI_ORDER='0\,1\,3\,4'

provision-contest/ansible/roles/hosts/tasks/main.yml

@@ -5,19 +5,11 @@
   hostname:
     name: "{{ inventory_hostname }}"
 
-# FIXME: this needs to be cleaned up and done in a way such that the
-# tasks are not marked as "changed" every time they are run, and also
-# work better with ad-hoc editing of the inventory hosts file.
-
-- name: add all hosts to hosts file
-  lineinfile:
+- name: Set new hosts file
+  template:
+    src: hosts.j2
     dest: /etc/hosts
-    regexp: '{{ item }}$'
-    line: "{{ hostvars[item].ansible_host }} {{ item }}"
-  loop: "{{ groups['all'] }}"
+    group: root
+    owner: root
+    mode: 0644
 
-- name: add domjudge in hosts file
-  lineinfile:
-    dest: /etc/hosts
-    regexp: 'domserver'
-    line: "{{ DOMSERVER_IP }} domjudge domserver"

provision-contest/ansible/roles/hosts/templates/hosts.j2

@@ -0,0 +1,15 @@
+127.0.0.1 localhost
+127.0.1.1 {{ inventory_hostname }}
+
+# The following lines are desirable for IPv6 capable hosts
+::1     ip6-localhost ip6-loopback
+fe00::0 ip6-localnet
+ff00::0 ip6-mcastprefix
+ff02::1 ip6-allnodes
+ff02::2 ip6-allrouters
+
+{{ DOMSERVER_IP }}             domjudge domserver
+{% for item in groups['all'] %}
+{{ hostvars[item].ansible_host }}              {{ item }}
+{% endfor %}
+