diff --git a/ruby/src/otel/Dockerfile b/ruby/src/otel/Dockerfile
index a0e8978d23..57b0a14682 100644
--- a/ruby/src/otel/Dockerfile
+++ b/ruby/src/otel/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:latest
+FROM ubuntu:latest@sha256:f3d28607ddd78734bb7f71f117f3c6706c666b8b76cbff7c9ff6e5718d46ff64
 
 RUN mkdir /build