ansible: fail fast, use pipelining, YAML errors

* fail fast: when a task fails for a given host, don't run the next
  tasks with other hosts
* use pipelining
* make yaml warnings into error

ansible.cfg

@@ -1,2 +1,6 @@
 [defaults]
 roles_path = playbooks/infrastructure/roles:playbooks/authorized_keys/roles:playbooks/backup/roles:playbooks/bind/roles:playbooks/icinga/roles:playbooks/postfix/roles:playbooks/weblate/roles:playbooks/packages/roles:playbooks/jdauphant.nginx/roles:playbooks/enough-nginx/roles:playbooks/certificate/roles:playbooks/wazuh/roles:playbooks/firewall/roles:playbooks/api/roles:playbooks/openvpn/roles:playbooks/jitsi/roles
+any_errors_fatal = True
+duplicate_dict_key = True
+[connection]
+pipelining = True

playbooks/infrastructure/playbook.yml

@@ -1,2 +1,3 @@
 ---
 - import_playbook: test-encrypted-volume.yml
+- import_playbook: test-pipelining.yml

playbooks/infrastructure/test-pipelining.yml

@@ -0,0 +1,6 @@
+- hosts: infrastructure1-host
+  connection: local
+  tasks:
+    - name: Check that pipelining is enabled
+      assert:
+        that: ansible_pipelining

tests/enough/common/test_ansible_utils.py

@@ -90,6 +90,24 @@ def test_get_variable():
     assert expected[variable] == value
 
 
+def test_pipelining_is_enabled(monkeypatch):
+    ansible = ansible_utils.Ansible(settings.CONFIG_DIR, settings.SHARE_DIR,
+                                    ['localhost,'])
+    ansible.bake()('all', '-llocalhost', '-massert',
+                   "-athat='ansible_pipelining'")
+
+
+def test_pipelining_is_enabled_2(monkeypatch):
+    ansible = ansible_utils.Ansible(settings.CONFIG_DIR, settings.SHARE_DIR,
+                                    ['localhost,'])
+
+    # environment variable takes precedence over ansible.cfg
+    monkeypatch.setenv('ANSIBLE_PIPELINING', 'False')
+    with pytest.raises(sh.ErrorReturnCode):
+        ansible.bake()('all', '-llocalhost', '-massert',
+                       "-athat='ansible_pipelining'")
+
+
 def test_get_role_variable():
     defaults = yaml.safe_load(open('playbooks/api/roles/api/defaults/main.yml'))
     variable = 'api_admin_password'