diff --git a/Dockerfile b/Dockerfile
index 6ac97aa..6a09ef9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,9 +1,9 @@
 ARG ALPINE_IMAGE
-ARG ALPINE_VERSION=3.14
-ARG ZT_COMMIT=e8f7d5ef9e7ba6be0b2163cfa31f8817ba5b18f4
-ARG ZT_VERSION=1.6.5
 
-FROM ${ALPINE_IMAGE}:${ALPINE_VERSION} as builder
+FROM ${ALPINE_IMAGE}:3.14 as builder
+
+ENV ZT_COMMIT=e8f7d5ef9e7ba6be0b2163cfa31f8817ba5b18f4
+ENV ZT_VERSION=1.6.5
 
 RUN apk add --update alpine-sdk linux-headers \
   && git clone --quiet https://github.com/zerotier/ZeroTierOne.git /src \
@@ -11,7 +11,7 @@ RUN apk add --update alpine-sdk linux-headers \
   && cd /src \
   && make -f make-linux.mk
 
-FROM ${ALPINE_IMAGE}:${ALPINE_VERSION}
+FROM ${ALPINE_IMAGE}:3.14
 LABEL version="${ZT_VERSION}"
 LABEL description="ZeroTier One as Docker Image"