test: improve purge expunged resources b/g task testcase (#9426)

* test: improve purge expunged resources b/g task testcase

Failures were seen for during purging of expunged resources via
bacground task during different test runs. This PR tries to make sure
b/g task execution is not skipped after MS restrat in a multi-MS
environment. It also updates expunged.resources.purge.interval to allow
running task again in 60s.

Signed-off-by: Abhishek Kumar <abhishek.mrt22@gmail.com>

* new string formatting

---------

Signed-off-by: Abhishek Kumar <abhishek.mrt22@gmail.com>

Author: shwstppr

test/integration/smoke/test_purge_expunged_vms.py

@@ -273,6 +273,7 @@ def restartAllManagementServers(self):
             return False
         self.debug("Restarting all management server")
         for idx, server_ip in enumerate(server_ips):
+            self.debug(f"Restarting management server #{idx} with IP {server_ip}")
             sshClient = SshClient(
                 server_ip,
                 22,
@@ -283,6 +284,9 @@ def restartAllManagementServers(self):
             sshClient.execute(command)
             command = "service cloudstack-management start"
             sshClient.execute(command)
+            if idx == 0:
+                # Wait before restarting other management servers to make the first as oldest running
+                time.sleep(10)
 
         # Waits for management to come up in 10 mins, when it's up it will continue
         timeout = time.time() + (10 * 60)
@@ -349,15 +353,18 @@ def test_05_purge_expunged_vm_service_offering(self):
     @skipTestIf("hypervisorIsSimulator")
     @attr(tags=["advanced"], required_hardware="true")
     def test_06_purge_expunged_vm_background_task(self):
-        purge_task_delay = 60
+        purge_task_delay = 120
         self.changeConfiguration('expunged.resources.purge.enabled', 'true')
         self.changeConfiguration('expunged.resources.purge.delay', purge_task_delay)
+        self.changeConfiguration('expunged.resources.purge.interval', int(purge_task_delay/2))
         self.changeConfiguration('expunged.resources.purge.keep.past.days', 1)
         if len(self.staticConfigurations) > 0:
             self.restartAllManagementServers()
-        wait = 2 * purge_task_delay
-        logging.info("Waiting for 2x%d = %d seconds for background task to execute" % (purge_task_delay, wait))
+        wait_multiple = 2
+        wait = wait_multiple * purge_task_delay
+        logging.info(f"Waiting for {wait_multiple}x{purge_task_delay} = {wait} seconds for background task to execute")
         time.sleep(wait)
+        logging.debug("Validating expunged VMs")
         self.validatePurgedVmEntriesInDb(
             [self.vm_ids[self.timestamps[0]], self.vm_ids[self.timestamps[1]], self.vm_ids[self.timestamps[2]]],
             None