Add the timestamp when creating the backup file (elastic#11034)

Fixes: elastic#10031

CHANGELOG.next.asciidoc

@@ -152,6 +152,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Report faulting file when config reload fails. {pull}[11304]11304
 - Remove IP fields from default_field in Elasticsearch template.
 - Fix a typo in libbeat/outputs/transport/client.go by updating `c.conn.LocalAddr()` to `c.conn.RemoteAddr()`. {pull}11242[11242]
+- Management configuration backup file will now have a timestamps in their name. {pull}11034[11034]
 
 *Auditbeat*
 

x-pack/libbeat/management/enroll.go

@@ -7,6 +7,7 @@ package management
 import (
 	"fmt"
 	"os"
+	"time"
 
 	"github.com/pkg/errors"
 
@@ -52,8 +53,10 @@ func Enroll(
 
 	configFile := cfgfile.GetDefaultCfgfile()
 
+	ts := time.Now().Unix()
+
 	// backup current settings:
-	backConfigFile := configFile + ".bak"
+	backConfigFile := configFile + "." + string(ts) + ".bak"
 	fmt.Println("Saving a copy of current settings to " + backConfigFile)
 	err = file.SafeFileRotate(backConfigFile, configFile)
 	if err != nil {

x-pack/libbeat/tests/system/test_management.py

@@ -1,5 +1,6 @@
 import sys
 import os
+import glob
 import json
 import requests
 import string
@@ -39,6 +40,8 @@ def test_enroll(self):
         Enroll the beat in Kibana Central Management
         """
 
+        assert len(glob.glob(os.path.join(self.working_dir, "mockbeat.yml.*.bak"))) == 0
+
         # We don't care about this as it will be replaced by enrollment
         # process:
         config_path = os.path.join(self.working_dir, "mockbeat.yml")
@@ -61,9 +64,9 @@ def test_enroll(self):
         assert config_content != new_content
 
         # Settings backup has been created
-        assert os.path.isfile(os.path.join(
-            self.working_dir, "mockbeat.yml.bak"))
-        backup_content = open(config_path + ".bak", 'r').read()
+        backup_file = glob.glob(os.path.join(self.working_dir, "mockbeat.yml.*.bak"))[0]
+        assert os.path.isfile(backup_file)
+        backup_content = open(backup_file).read()
         assert config_content == backup_content
 
     @unittest.skipIf(not INTEGRATION_TESTS,