diff --git a/Dockerfile b/Dockerfile
index d76b34f..0dd535e 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -9,8 +9,6 @@ FROM alpine:3.8
 
 COPY --from=downloader /prometheus-pingdom-exporter /prometheus-pingdom-exporter
 
-RUN apk add --no-cache ca-certificates
-
-EXPOSE 8000
+RUN apk --no-cache add ca-certificates
 
 ENTRYPOINT ["/prometheus-pingdom-exporter"]