made environment file for the service.

I am unable to reproduce systemctl set-environment to work as
advertized.

roles/mariadb/tasks/main.yml

@@ -41,9 +41,17 @@
 - name: start service at boot.
   command: systemctl reenable mysql.service
 
+- name: create environment file for systemd
+  copy:
+    content: ""
+    dest: /srv/mariadb/systemd_environment
+    mode: 0644
+
 # This mimics galera_new_cluster.sh
 - name: Initialize a new cluster.
-  command: systemctl set-environment _WSREP_NEW_CLUSTER='--wsrep-new-cluster'
+  lineinfile:
+    path: /srv/mariadb/systemd_environment
+    line: _WSREP_NEW_CLUSTER='--wsrep-new-cluster'
   when: groups['databases'] | length >= 3 and ansible_hostname == hostname_node0
 
 - name: make sure service is started
@@ -52,4 +60,7 @@
     state: started
 
 - name: Prevent cluster re-initialization
-  command: systemctl set-environment _WSREP_NEW_CLUSTER=''
+  lineinfile:
+    path: /srv/mariadb/systemd_environment
+    state: absent
+    line: _WSREP_NEW_CLUSTER='--wsrep-new-cluster'

roles/mariadb/templates/mysql.service

@@ -6,6 +6,7 @@ Requires=docker.service
 [Service]
 TimeoutStartSec=0
 Restart=always
+EnvironmentFile=/srv/mariadb/systemd_environment
 ExecStartPre=-/usr/bin/docker kill %n || /bin/true
 ExecStartPre=-/usr/bin/docker rm %n
 ExecStartPre=/usr/bin/docker pull mariadb:10.2