Use ansible_service_mgr fact

This patch removes some extra tasks for detecting systemd and uses
the `ansible_service_mgr` fact instead.

Partial-Bug: #1640125
Change-Id: I1a30b79a759057afb74f24f2239f474b60c1db35

handlers/main.yml

@@ -16,7 +16,7 @@
 - name: Reload the systemd daemon
   command: "systemctl daemon-reload"
   when:
-    - pid1_name == "systemd"
+    - ansible_service_mgr == 'systemd'
 
 - name: Restart mysql
   service:

tasks/galera_post_install.yml

@@ -88,7 +88,7 @@
     src: "upstart.limits.conf.j2"
     dest: "/etc/security/limits.conf"
   when:
-    - pid1_name != "systemd"
+    - ansible_service_mgr == 'systemd'
   notify:
     - Restart mysql
   tags:
@@ -102,15 +102,15 @@
     owner: "root"
     mode: "0755"
   when:
-    - pid1_name == "systemd"
+    - ansible_service_mgr == 'systemd'
 
 - name: Apply resource limits (systemd)
   template:
     src: "systemd.limits.conf.j2"
     dest: "/etc/systemd/system/mariadb.service.d/limits.conf"
     mode: "0644"
   when:
-    - pid1_name == "systemd"
+    - ansible_service_mgr == 'systemd'
   notify:
     - Reload the systemd daemon
     - Restart mysql

tasks/main.yml

@@ -36,19 +36,6 @@
   tags:
     - always
 
-- name: Check init system
-  command: cat /proc/1/comm
-  changed_when: false
-  register: _pid1_name
-  tags:
-    - always
-
-- name: Set the name of pid1
-  set_fact:
-    pid1_name: "{{ _pid1_name.stdout }}"
-  tags:
-    - always
-
 - include: galera_upgrade_check.yml
 - include: galera_cluster_state.yml
 - include: galera_pre_install.yml