attempt to fix systemd in chroot env

fixes #21026

lib/ansible/modules/system/systemd.py

@@ -297,6 +297,7 @@ def main():
 
     # check service data, cannot error out on rc as it changes across versions, assume not found
     (rc, out, err) = module.run_command("%s show '%s'" % (systemctl, unit))
+
     if rc == 0:
         # load return of systemctl show into dictionary for easy access and return
         multival = []
@@ -327,6 +328,18 @@ def main():
             if is_systemd and 'LoadError' in result['status']:
                 module.fail_json(msg="Error loading unit file '%s': %s" % (unit, result['status']['LoadError']))
 
+    elif out.find('ignoring request') != -1:
+        # fallback list-unit-files as show does not work on some systems (chroot)
+        # not used as primary as it skips some services (like those using init.d) and requires .service notation
+        if unit.endswith('.service'):
+            service = unit
+        else:
+            service = '%s.service' % unit
+        (rc, out, err) = module.run_command("%s list-unit-files '%s'" % (systemctl, service))
+        if rc == 0:
+            is_systemd = True
+
+
     # Does service exist?
     found = is_systemd or is_initd
     if is_initd and not is_systemd: