diff --git a/tools/dockerfile/interoptest/grpc_interop_php8/Dockerfile b/tools/dockerfile/interoptest/grpc_interop_php8/Dockerfile
index 26733988973d7..60d2121747e86 100644
--- a/tools/dockerfile/interoptest/grpc_interop_php8/Dockerfile
+++ b/tools/dockerfile/interoptest/grpc_interop_php8/Dockerfile
@@ -121,3 +121,4 @@ RUN curl -sSL --fail --retry 5 -o ccache.tar.gz https://github.com/ccache/ccache
 
 
 RUN mkdir /var/local/jenkins
+