docker compose: switch to valkey as message broker

Author: valentijnscholten

docs/content/en/open_source/upgrading/2.52.md

@@ -9,4 +9,25 @@ Since the license change at Redis the fork ValKey has become widely popular and
 
 Defect Dojo 2.52 now uses ValKey as a message broker. Teh existing redit volume can be used by Valkey, so this is just a drop in replacement.
 
-If you want to know more or have a setup where you cannot just re-use the existing volume, please visit https://valkey.io/topics/migration/.
+If you want to know more or have a setup where you cannot just re-use the existing volume, please visit https://valkey.io/topics/migration/.
+
+When you shutdown Defect Dojo to perform the upgrade, the celery tasks that are in the queue are storede to disk. After the upgrade, the celery workers will process these tasks as normal.
+
+If you want to be 110% sure no tasks will be lost you could perform the upgrade in two steps:
+
+1) Stop nginx, uwsgi, celerybeat to prevent new tasks from being created:
+
+`docker compose down nginx, uwsgi, celerybeat`
+
+2) Observe the logs of the celeryworker(s) and wait until all tasks are finished:
+
+`docker compose logs celeryworker`
+
+3) Stop the remaining services:
+
+`docker compose down`
+
+4) Continue the upgrade as normal per the [upgrade guide](upgrading_guide)
+`docker compose pull`
+`docker compose up -d`
+