diff --git a/env.sh.template b/env.sh.template
index b479aee..d9248ba 100755
--- a/env.sh.template
+++ b/env.sh.template
@@ -2,3 +2,5 @@
 
 # https://prometheus.io/docs/prometheus/latest/storage/#operational-aspects
 export retention_time="15d"
+
+export cli_options="--storage.tsdb.retention.time=$retention_time --storage.tsdb.path=/app/data/runtime"
diff --git a/start.sh b/start.sh
index e987933..2e8f32b 100755
--- a/start.sh
+++ b/start.sh
@@ -18,8 +18,13 @@ if [[ ! -f /app/data/env.sh ]]; then
     cp /app/pkg/env.sh.template /app/data/env.sh
 fi
 
-echo "=> Source custom variables"
+# migration remove in next release
+if ! grep -q cli_option /app/data/env.sh; then
+    echo -e '\nexport cli_options="--storage.tsdb.retention.time=$retention_time --storage.tsdb.path=/app/data/runtime"' >> /app/data/env.sh
+fi
+
+echo "=> Source custom variables for cli args"
 source /app/data/env.sh
 
-echo "=> Starting Prometheus with retention time of $retention_time"
-exec /usr/local/bin/gosu cloudron:cloudron /app/code/prometheus --config.file=/app/data/config/prometheus.yml --storage.tsdb.path=/app/data/runtime --storage.tsdb.retention.time="${retention_time:-15d}"
+echo "=> Starting Prometheus"
+exec /usr/local/bin/gosu cloudron:cloudron /app/code/prometheus --config.file=/app/data/config/prometheus.yml ${cli_options}