diff --git a/Makefile b/Makefile
index d2505b2..3f08dd0 100644
--- a/Makefile
+++ b/Makefile
@@ -1,9 +1,16 @@
 .PHONY: ami
-ami: build/convert
+
+ami: convert
+	packer build -var-file=build/variables.json build/alpine-ami.json
+
+edge: convert
+	@echo '{ "alpine_release": "edge", "ami_release": "'`date +%Y%m%d%H%M%S`'" }' > build/edge.json
+	packer build -var-file=build/variables.json -var-file=build/edge.json build/alpine-ami.json
+
+convert: build/convert
 	[ -f variables.yaml ] || cp variables.yaml-default variables.yaml
 	build/convert variables.yaml > build/variables.json
 	build/convert alpine-ami.yaml > build/alpine-ami.json
-	packer build -var-file=build/variables.json build/alpine-ami.json
 
 build/convert:
 	[ -d ".py3" ] || python3 -m venv .py3
diff --git a/alpine-ami.yaml b/alpine-ami.yaml
index 0ec2e21..8baabc0 100644
--- a/alpine-ami.yaml
+++ b/alpine-ami.yaml
@@ -1,10 +1,9 @@
 variables:
 
-  # NOTE:  Configuration is done with a `variables.yaml` file.  If it doesn't
-  # exist, default configuration is copied from `variables.yaml-default`.
+  # NOTE:  Configuration is done with a 'variables.yaml' file.  If it doesn't
+  # exist, default configuration is copied from 'variables.yaml-default'.
 
-  # NOTE:  Changing alpine_release requires modifying `make_ami.sh` -- don't
-  # override this in `variables.json`!
+  # NOTE:  Changing alpine_release may require modifying 'make_ami.sh'.
   alpine_release: "3.8"
 
 
@@ -55,4 +54,6 @@ builders:
 provisioners:
   - type: "shell"
     script: "make_ami.sh"
+    environment_vars:
+      - "ALPINE_RELEASE={{user `alpine_release`}}"
     execute_command: 'sudo sh -c "{{ .Vars }} {{ .Path }} ''{{user `add_repos`}}'' ''{{user `add_pkgs`}}''"'
diff --git a/make_ami.sh b/make_ami.sh
index 0d10058..9b24227 100755
--- a/make_ami.sh
+++ b/make_ami.sh
@@ -3,12 +3,14 @@
 
 set -eu
 
-: ${ALPINE_RELEASE:="3.8"}  # not tested against edge
+: ${MIN_RELEASE:="3.8"}
 : ${APK_TOOLS_URI:="https://github.com/alpinelinux/apk-tools/releases/download/v2.10.0/apk-tools-2.10.0-x86_64-linux.tar.gz"}
 : ${APK_TOOLS_SHA256:="77f2d256fcd5d6fdafadf43bb6a9c85c3da7bb471ee842dcd729175235cb9fed"}
 : ${ALPINE_KEYS:="http://dl-cdn.alpinelinux.org/alpine/v3.8/main/x86_64/alpine-keys-2.1-r1.apk"}
 : ${ALPINE_KEYS_SHA256:="f7832b848cedca482b145011cf516e82392f02a10713875cb09f39c7221c6f17"}
 
+: ${ALPINE_RELEASE:="${MIN_RELEASE}"}   # unless otherwise specified
+
 die() {
     printf '\033[1;31mERROR:\033[0m %s\n' "$@" >&2  # bold red
     exit 1
@@ -75,13 +77,26 @@ setup_repositories() {
     local add_repos="$2"  # extra repo lines, comma separated
 
     mkdir -p "$target"/etc/apk/keys
-    cat > "$target"/etc/apk/repositories <<EOF
+
+    if [ "$ALPINE_RELEASE" = 'edge' ]; then
+        cat > "$target"/etc/apk/repositories <<EOF
+http://dl-cdn.alpinelinux.org/alpine/edge/main
+http://dl-cdn.alpinelinux.org/alpine/edge/community
+http://dl-cdn.alpinelinux.org/alpine/edge/testing
+EOF
+    else
+        cat > "$target"/etc/apk/repositories <<EOF
 http://dl-cdn.alpinelinux.org/alpine/v$ALPINE_RELEASE/main
 http://dl-cdn.alpinelinux.org/alpine/v$ALPINE_RELEASE/community
+EOF
+    fi
+    # NOTE: until several key packages graduate from edge...
+    cat >> "$target"/etc/apk/repositories <<EOF
 @edge-main http://dl-cdn.alpinelinux.org/alpine/edge/main
 @edge-community http://dl-cdn.alpinelinux.org/alpine/edge/community
 @edge-testing http://dl-cdn.alpinelinux.org/alpine/edge/testing
 EOF
+
     echo "$add_repos" | tr , "\012" >> "$target"/etc/apk/repositories
 }
 
@@ -269,6 +284,8 @@ cleanup() {
 
 main() {
     [ "$#" -ne 2 ] && { echo "usage: $0 '<repo>[,<repo>]' '<pkg>[,<pkg>]'"; exit 1; }
+    [ "$ALPINE_RELEASE" != 'edge' ] && [[ "$ALPINE_RELEASE" -lt "$MIN_RELEASE" ]] && \
+        { echo "ERR: minimum alpine_release value must be '$MIN_RELEASE'"; exit 1; }
 
     local add_repos="$1"
     local add_pkgs="$2"