lxc-alpine: use dl-cdn.a.o as default mirror instead of random one

templates/lxc-alpine.in

@@ -46,7 +46,7 @@ ebf31683b56410ecc4c00acd9f6e2839e237a3b62b5ae7ef686705c7ba0396a9  alpine-devel@l
 12f899e55a7691225603d6fb3324940fc51cd7f133e7ead788663c2b7eecb00c  alpine-devel@lists.alpinelinux.org-5261cecb.rsa.pub"
 
 readonly APK_KEYS_URI='http://alpinelinux.org/keys'
-readonly MIRRORS_LIST_URL='http://rsync.alpinelinux.org/alpine/MIRRORS.txt'
+readonly DEFAULT_MIRROR_URL='http://dl-cdn.alpinelinux.org/alpine'
 
 : ${APK_KEYS_DIR:=/etc/apk/keys}
 if ! ls "$APK_KEYS_DIR"/alpine* >/dev/null 2>&1; then
@@ -76,7 +76,7 @@ usage() {
 		                          to the host arch.
 		   -d, --debug            Run this script in a debug mode (set -x and wget w/o -q).
 		   -F, --flush-cache      Remove cached files before build.
-		   -m URL --mirror=URL    The Alpine mirror to use; defaults to random mirror.
+		   -m URL --mirror=URL    The Alpine mirror to use; defaults to $DEFAULT_MIRROR_URL.
 		   -r VER, --release=VER  The Alpine release branch to install; default is the
 		                          latest stable.
 
@@ -130,11 +130,6 @@ parse_arch() {
 	esac
 }
 
-random_mirror_url() {
-	local url=$(fetch "$MIRRORS_LIST_URL" | shuf -n 1)
-	[ -n "$url" ] && echo "$url"
-}
-
 run_exclusively() {
 	local lock_name="$1"
 	local timeout=$2
@@ -475,7 +470,7 @@ extra_packages="$@"
 # Set global variables.
 readonly DEBUG="$debug"
 readonly FLUSH_CACHE="$flush_cache"
-readonly MIRROR_URL="${mirror_url:-$(random_mirror_url)}"
+readonly MIRROR_URL="${mirror_url:-$DEFAULT_MIRROR_URL}"
 
 # Validate options.
 [ -n "$name" ] || die 1 'Missing required option --name'