Ensure that selected Apache MPM is enforced

At the moment services might have different MPM selected while all
operating the same Apache setup, ie on metal setup.
This results in failures to set selected MPMs, so eventually second run
of roles after initial deployment will end up in failure (ie upgrade).

This patch ensures that all except selected MPMs are disabled and do
role get's the desired state of deployment.

We also need to align selected MPM across all roles to avoid
future conflicts.

Change-Id: I6c7503794ec9b66ec54d8dd2ae81ad914aa3d389

defaults/main.yml

@@ -45,6 +45,7 @@ repo_apache_default_sites: "{{ _repo_apache_default_sites }}"
 repo_apache_log_level: info
 # List of modules to enable are respected only for Debian Family
 repo_apache_modules: "{{ _repo_apache_modules }}"
+repo_apache_mpms: "{{ _repo_apache_mpms }}"
 
 # MPM tunables
 repo_apache_mpm_backend: "{{ openstack_apache_mpm_backend | default('event') }}"

tasks/repo_post_install.yml

@@ -19,6 +19,28 @@
     name: pack.threads
     value: '0'
 
+- name: Ensure apache2 MPM for Debian/Ubuntu
+  apache2_module:
+    name: "{{ item.name }}"
+    state: "{{ item.state }}"
+    ignore_configcheck: yes
+    warn_mpm_absent: false
+  with_items: "{{ repo_apache_mpms | sort(attribute='state') }}"
+  when:
+    - ansible_facts['pkg_mgr'] == 'apt'
+  notify: Restart web server
+
+- name: Ensure apache2 MPM for EL
+  copy:
+    content: |
+      LoadModule mpm_{{ repo_apache_mpm_backend }}_module modules/mod_mpm_{{ repo_apache_mpm_backend }}.so
+
+    dest: /etc/httpd/conf.modules.d/00-mpm.conf
+    mode: "0644"
+  when:
+    - ansible_facts['pkg_mgr'] == 'dnf'
+  notify: Restart web server
+
 - name: Enable apache2 modules
   apache2_module:
     name: "{{ item.name }}"

vars/debian.yml

@@ -19,11 +19,17 @@ _repo_system_service_name: apache2
 
 _repo_vhost_enable_path: "/etc/{{ repo_system_service_name }}/sites-enabled"
 
+_repo_apache_mpms:
+  - name: "mpm_event"
+    state: "{{ (repo_apache_mpm_backend == 'event') | ternary('present', 'absent') }}"
+  - name: "mpm_worker"
+    state: "{{ (repo_apache_mpm_backend == 'worker') | ternary('present', 'absent') }}"
+  - name: "mpm_prefork"
+    state: "{{ (repo_apache_mpm_backend == 'prefork') | ternary('present', 'absent') }}"
+
 _repo_apache_modules:
   - name: "ssl"
     state: "present"
-  - name: "mpm_{{ repo_apache_mpm_backend }}"
-    state: "present"
   - name: "rewrite"
     state: "present"
   - name: "headers"