@@ -6,7 +6,7 @@ mkimg="$(basename "$0")"

 usage() {

 	echo >&2 "usage: $mkimg [-d dir] [-t tag] script [script-args]"

 	echo >&2 "   ie: $mkimg -t someuser/debian debootstrap --variant=minbase jessie"

-	echo >&2 "       $mkimg -t someuser/ubuntu debootstrap --include=ubuntu-minimal trusty"

+	echo >&2 "       $mkimg -t someuser/ubuntu debootstrap --include=ubuntu-minimal --components main,universe trusty"

 	echo >&2 "       $mkimg -t someuser/busybox busybox-static"

 	echo >&2 "       $mkimg -t someuser/centos:5 rinse --distribution centos-5"

 	exit 1

@@ -23,9 +23,14 @@ shift

 # now for some Docker-specific tweaks

 # prevent init scripts from running during install/update

-echo >&2 "+ cat > '$rootfsDir/usr/sbin/policy-rc.d'"

+echo >&2 "+ echo exit 101 > '$rootfsDir/usr/sbin/policy-rc.d'"

 cat > "$rootfsDir/usr/sbin/policy-rc.d" <<'EOF'

 #!/bin/sh

+

+# For most Docker users, "apt-get install" only happens during "docker build",

+# where starting services doesn't work and often fails in humorous ways. This

+# prevents those failures by stopping the services from attempting to start.

+

 exit 101

 EOF

 chmod +x "$rootfsDir/usr/sbin/policy-rc.d"

@@ -34,17 +39,25 @@ chmod +x "$rootfsDir/usr/sbin/policy-rc.d"

 (

 	set -x

 	chroot "$rootfsDir" dpkg-divert --local --rename --add /sbin/initctl

-	ln -sf /bin/true "$rootfsDir/sbin/initctl"

+	cp -a "$rootfsDir/usr/sbin/policy-rc.d" "$rootfsDir/sbin/initctl"

+	sed -i 's/^exit.*/exit 0/' "$rootfsDir/sbin/initctl"

 )

-# shrink the image, since apt makes us fat (wheezy: ~157.5MB vs ~120MB)

+# shrink a little, since apt makes us cache-fat (wheezy: ~157.5MB vs ~120MB)

 ( set -x; chroot "$rootfsDir" apt-get clean )

 # Ubuntu 10.04 sucks... :)

 if strings "$rootfsDir/usr/bin/dpkg" | grep -q unsafe-io; then

 	# force dpkg not to call sync() after package extraction (speeding up installs)

 	echo >&2 "+ echo force-unsafe-io > '$rootfsDir/etc/dpkg/dpkg.cfg.d/docker-apt-speedup'"

-	echo 'force-unsafe-io' > "$rootfsDir/etc/dpkg/dpkg.cfg.d/docker-apt-speedup"

+	cat > "$rootfsDir/etc/dpkg/dpkg.cfg.d/docker-apt-speedup" <<-'EOF'

+	# For most Docker users, package installs happen during "docker build", which

+	# doesn't survive power loss and gets restarted clean afterwards anyhow, so

+	# this minor tweak gives us a nice speedup (much nicer on spinning disks,

+	# obviously).

+

+	force-unsafe-io

+	EOF

 fi

 if [ -d "$rootfsDir/etc/apt/apt.conf.d" ]; then

@@ -52,16 +65,36 @@ if [ -d "$rootfsDir/etc/apt/apt.conf.d" ]; then

 	aptGetClean='"rm -f /var/cache/apt/archives/*.deb /var/cache/apt/archives/partial/*.deb /var/cache/apt/*.bin || true";'

 	echo >&2 "+ cat > '$rootfsDir/etc/apt/apt.conf.d/docker-clean'"

 	cat > "$rootfsDir/etc/apt/apt.conf.d/docker-clean" <<-EOF

+		# Since for most Docker users, package installs happen in "docker build" steps,

+		# they essentially become individual layers due to the way Docker handles

+		# layering, especially using CoW filesystems.  What this means for us is that

+		# the caches that APT keeps end up just wasting space in those layers, making

+		# our layers unnecessarily large (especially since we'll normally never use

+		# these caches again and will instead just "docker build" again and make a brand

+		# new image).

+

+		# Ideally, these would just be invoking "apt-get clean", but in our testing,

+		# that ended up being cyclic and we got stuck on APT's lock, so we get this fun

+		# creation that's essentially just "apt-get clean".

 		DPkg::Post-Invoke { ${aptGetClean} };

 		APT::Update::Post-Invoke { ${aptGetClean} };

 		Dir::Cache::pkgcache "";

 		Dir::Cache::srcpkgcache "";

+

+		# Note that we do realize this isn't the ideal way to do this, and are always

+		# open to better suggestions (https://github.com/dotcloud/docker/issues).

 	EOF

 	# remove apt-cache translations for fast "apt-get update"

-	echo >&2 "+ cat > '$rootfsDir/etc/apt/apt.conf.d/docker-no-languages'"

-	echo 'Acquire::Languages "none";' > "$rootfsDir/etc/apt/apt.conf.d/docker-no-languages"

+	echo >&2 "+ echo Acquire::Languages 'none' > '$rootfsDir/etc/apt/apt.conf.d/docker-no-languages'"

+	cat > "$rootfsDir/etc/apt/apt.conf.d/docker-no-languages" <<-'EOF'

+	# In Docker, we don't often need the "Translations" files, so we're just wasting

+	# time and space by downloading them, and this inhibits that.  For users that do

+	# need them, it's a simple matter to delete this file and "apt-get update". :)

+

+	Acquire::Languages "none";

+	EOF

 fi

 if [ -z "$DONT_TOUCH_SOURCES_LIST" ]; then

@@ -76,39 +109,53 @@ if [ -z "$DONT_TOUCH_SOURCES_LIST" ]; then

 	if [ -z "$lsbDist" -a -r "$rootfsDir/etc/debian_version" ]; then

 		lsbDist='Debian'

 	fi

+	# normalize to lowercase for easier matching

+	lsbDist="$(echo "$lsbDist" | tr '[:upper:]' '[:lower:]')"

 	case "$lsbDist" in

-		debian|Debian)

+		debian)

 			# updates and security!

 			if [ "$suite" != 'sid' -a "$suite" != 'unstable' ]; then

 				(

 					set -x

-					sed -i "p; s/ $suite main$/ ${suite}-updates main/" "$rootfsDir/etc/apt/sources.list"

+					sed -i "

+						p;

+						s/ $suite / ${suite}-updates /

+					" "$rootfsDir/etc/apt/sources.list"

 					echo "deb http://security.debian.org $suite/updates main" >> "$rootfsDir/etc/apt/sources.list"

+					# LTS

+					if [ "$suite" = 'squeeze' ]; then

+						head -1 "$rootfsDir/etc/apt/sources.list" \

+							| sed "s/ $suite / ${suite}-lts /" \

+								>> "$rootfsDir/etc/apt/sources.list"

+					fi

 				)

 			fi

 			;;

-		ubuntu|Ubuntu)

-			# add the universe, updates, and security repositories

+		ubuntu)

+			# add the updates and security repositories

 			(

 				set -x

 				sed -i "

-					s/ $suite main$/ $suite main universe/; p;

-					s/ $suite main/ ${suite}-updates main/; p;

-					s/ $suite-updates main/ ${suite}-security main/

+					p;

+					s/ $suite / ${suite}-updates /; p;

+					s/ $suite-updates / ${suite}-security /

 				" "$rootfsDir/etc/apt/sources.list"

 			)

 			;;

-		tanglu|Tanglu)

+		tanglu)

 			# add the updates repository

 			if [ "$suite" != 'devel' ]; then

 				(

 					set -x

-					sed -i "p; s/ $suite main$/ ${suite}-updates main/" "$rootfsDir/etc/apt/sources.list"

+					sed -i "

+						p;

+						s/ $suite / ${suite}-updates /

+					" "$rootfsDir/etc/apt/sources.list"

 				)

 			fi

 			;;

-		steamos|SteamOS)

-			# add contrib and non-free

+		steamos)

+			# add contrib and non-free if "main" is the only component

 			(

 				set -x

 				sed -i "s/ $suite main$/ $suite main contrib non-free/" "$rootfsDir/etc/apt/sources.list"