use debian base image

experiments/Dockerfile

@@ -1,12 +1,11 @@
-FROM alpine:latest
+FROM debian:bullseye-slim
 # LABEL maintainer=""
 
 RUN set -ex; \
     \
-    apk --no-cache add \
+    apt-get update; apt-get -y --no-install-recommends install \
       easy-rsa \
-    ; \
+    ; rm -rf /var/lib/apt/lists/*; \
     ln -s /usr/share/easy-rsa/easyrsa /usr/local/bin;
 
 WORKDIR "/opt/openvpn"
-