diff --git a/roles/prometheus/tasks/main.yml b/roles/prometheus/tasks/main.yml
index b14ad00..54d4e6a 100644
--- a/roles/prometheus/tasks/main.yml
+++ b/roles/prometheus/tasks/main.yml
@@ -9,7 +9,7 @@
     docker_command:
       - "--config.file=/etc/prometheus/prometheus.yml"
       - "--storage.tsdb.path=/prometheus"
-      - "--storage.tsdb.retention={{ prometheus_storage_retention }}"
+      - "--storage.tsdb.retention.time={{ prometheus_storage_retention }}"
       - "--web.console.libraries=/usr/share/prometheus/console_libraries"
       - "--web.console.templates=/usr/share/prometheus/consoles"
     docker_mounts: