diff --git a/Dockerfile b/Dockerfile
index ef3f311..c5897f4 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM docker:latest
+FROM docker:latest@sha256:a6dd5322747a95cd8e3207bd8d415a8fd20ec34e9c00f06dc019cbd912013489
 COPY start-redis.sh /start-redis.sh
 RUN chmod +x /start-redis.sh
 ENTRYPOINT ["/start-redis.sh"]