diff --git a/Dockerfile b/Dockerfile
index 5469993..f41b59a 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,7 +5,7 @@ ENV CONFD_VERSION=v0.12.0-alpha3
 RUN apk add --no-cache go git gcc musl-dev && \
     git clone https://github.com/kelseyhightower/confd.git /src/confd && \
     cd /src/confd && \
-    git checkout -q --detach "v$CONFD_VERSION" && \
+    git checkout -q --detach "$CONFD_VERSION" && \
     cd /src/confd/src/github.com/kelseyhightower/confd && \
     GOPATH=/src/confd/vendor:/src/confd go build -a -installsuffix cgo -ldflags '-extld ld -extldflags -static' -x . && \
     mv ./confd /bin/ && \