debvm-create: add a --skip option

As with mmdebstrap, the --skip option can be used to skip over
tasks that are enabled by default. For now, we just add an integration
for

1 files changed, 54 insertions, 25 deletions

diff --git a/debvm-create b/debvm-create
index 58094cc..f3f9895 100755
--- a/debvm-create
+++ b/debvm-create
@@ -11,7 +11,7 @@ debvm-create - Create a VM image for various Debian releases and architectures
 
 =head1 SYNOPSIS
 
-B<debvm-create> [B<-a> I<architecture>] [B<-h> I<hostname>] [B<-k> I<sshkey>] [B<-m> I<mirror>] [B<-o> I<output>] [B<-p> I<package>] [B<-r> I<release>] [B<-z> I<size_in_GB>] [B<--> I<mmdebstrap options>]
+B<debvm-create> [B<-a> I<architecture>] [B<-h> I<hostname>] [B<-k> I<sshkey>] [B<-m> I<mirror>] [B<-o> I<output>] [B<-p> I<package>] [B<-r> I<release>] [B<-s> <task>] [B<-z> I<size_in_GB>] [B<--> I<mmdebstrap options>]
 
 =head1 DESCRIPTION
 
@@ -66,6 +66,19 @@ If a linux-image is passed here, it will replace the one selected by default.
 Use the given Debian release.
 By default, B<unstable> is being used.
 
+=item B<-s> I<task>, B<--skip>=I<task>
+
+Skip a particular task or feature.
+The option may be specified multiple times or list multiple tasks to be skipped by separating them with a comma.
+By default, no tasks are skipped.
+The following tasks may be skipped.
+
+=over 4
+
+=item B<systemdnetwork> skips installing B<libnss-resolve> as well as automatic network configuration via B<systemd-networkd>.
+
+=back
+
 =item B<-z> I<size_in_GB>, B<--size>=I<size_in_GB>
 
 Specify the minimum image size in giga bytes.
@@ -93,6 +106,7 @@ IMAGE=rootfs.ext4
 INCLUDE_PACKAGES=init
 MIRROR="http://deb.debian.org/debian"
 SIZE=$((1024*1024*1024))
+SKIP=,
 SSHKEY=
 SUITE=unstable
 VMNAME=testvm
@@ -123,6 +137,9 @@ opt_hostname() {
 opt_mirror() {
 	MIRROR=$1
 }
+opt_skip() {
+	SKIP="$SKIP$1,"
+}
 opt_sshkey() {
 	SSHKEY=$1
 }
@@ -139,7 +156,7 @@ opt_size() {
 	SIZE=$(($1*1024*1024*1024))
 }
 
-while getopts :a:h:k:m:o:p:r:z:-: OPTCHAR; do
+while getopts :a:h:k:m:o:p:r:s:z:-: OPTCHAR; do
 	case "$OPTCHAR" in
 		a)	opt_architecture "$OPTARG"	;;
 		h)	opt_hostname "$OPTARG"		;;
@@ -148,18 +165,19 @@ while getopts :a:h:k:m:o:p:r:z:-: OPTCHAR; do
 		o)	opt_output "$OPTARG"		;;
 		p)	opt_package "$OPTARG"		;;
 		r)	opt_release "$OPTARG"		;;
+		s)	opt_skip "$OPTARG"		;;
 		z)	opt_size "$OPTARG"		;;
 		-)
 			case "$OPTARG" in
 				help)
 					usage
 				;;
-				architecture|hostname|mirror|output|package|release|size|sshkey)
+				architecture|hostname|mirror|output|package|release|size|skip|sshkey)
 					test "$OPTIND" -gt "$#" && usage_error "missing argument for --$OPTARG"
 					"opt_$OPTARG" "$(nth_arg "$OPTIND" "$@")"
 					OPTIND=$((OPTIND+1))
 				;;
-				architecture=*|hostname=*|mirror=*|output=*|package=*|release=*|size=*|sshkey=*)
+				architecture=*|hostname=*|mirror=*|output=*|package=*|release=*|size=*|skip=*|sshkey=*)
 					"opt_${OPTARG%%=*}" "${OPTARG#*=}"
 				;;
 				*)
@@ -184,6 +202,13 @@ if test -n "$SSHKEY" && ! test -f "$SSHKEY"; then
 	die "error: ssh keyfile '$SSHKEY' not found"
 fi
 
+check_skip() {
+	case "$SKIP" in
+		*",$1,"*)	return 0 ;;
+		*)		return 1 ;;
+	esac
+}
+
 case "$SUITE" in
 	jessie)
 		DEBVER=8
@@ -251,17 +276,19 @@ if test -n "$SSHKEY"; then
 	INCLUDE_PACKAGES="$INCLUDE_PACKAGES,openssh-server"
 fi
 
-# add a DNS resolver
-if test "$DEBVER" -ge 9; then
-	INCLUDE_PACKAGES="$INCLUDE_PACKAGES,libnss-resolve"
-fi
-if test "$DEBVER" -le 11; then
-	set -- '--customize-hook=chroot "$1" systemctl enable systemd-resolved.service' "$@"
-fi
-if test "$DEBVER" -le 9; then
-	set -- '--customize-hook=ln -fs ../run/systemd/resolve/resolv.conf "$1/etc/resolv.conf"' "$@"
-elif test "$DEBVER" -le 11; then
-	set -- '--customize-hook=ln -fs ../run/systemd/resolve/stub-resolv.conf "$1/etc/resolv.conf"' "$@"
+if ! check_skip systemdnetwork; then
+	# add a DNS resolver
+	if test "$DEBVER" -ge 9; then
+		INCLUDE_PACKAGES="$INCLUDE_PACKAGES,libnss-resolve"
+	fi
+	if test "$DEBVER" -le 11; then
+		set -- '--customize-hook=chroot "$1" systemctl enable systemd-resolved.service' "$@"
+	fi
+	if test "$DEBVER" -le 9; then
+		set -- '--customize-hook=ln -fs ../run/systemd/resolve/resolv.conf "$1/etc/resolv.conf"' "$@"
+	elif test "$DEBVER" -le 11; then
+		set -- '--customize-hook=ln -fs ../run/systemd/resolve/stub-resolv.conf "$1/etc/resolv.conf"' "$@"
+	fi
 fi
 
 # construct mmdebstrap options as $@:
@@ -284,16 +311,18 @@ set -- \
 # allow password-less root login
 set -- '--customize-hook=chroot "$1" passwd --delete root' "$@"
 
-# dhcp on all network interfaces
-SYSD_NET_MATCH='Name=en*\n'
-test "$DEBVER" -le 8 && SYSD_NET_MATCH="${SYSD_NET_MATCH}Name=eth*\\n"
-SYSD_NET_NET='DHCP=yes\n'
-# This anchor is included by default since bullseye. Fails DNSSEC validation when missing.
-test "$DEBVER" -le 11 && SYSD_NET_NET="${SYSD_NET_NET}DNSSECNegativeTrustAnchors=home.arpa\\n"
-set -- \
-	'--customize-hook=chroot "$1" systemctl enable systemd-networkd.service' \
-	"--customize-hook=printf \"[Match]\\n$SYSD_NET_MATCH\\n[Network]\\n$SYSD_NET_NET"'\n[DHCP]\nUseDomains=yes\n" > "$1/etc/systemd/network/20-wired.network"' \
-	"$@"
+if ! check_skip systemdnetwork; then
+	# dhcp on all network interfaces
+	SYSD_NET_MATCH='Name=en*\n'
+	test "$DEBVER" -le 8 && SYSD_NET_MATCH="${SYSD_NET_MATCH}Name=eth*\\n"
+	SYSD_NET_NET='DHCP=yes\n'
+	# This anchor is included by default since bullseye. Fails DNSSEC validation when missing.
+	test "$DEBVER" -le 11 && SYSD_NET_NET="${SYSD_NET_NET}DNSSECNegativeTrustAnchors=home.arpa\\n"
+	set -- \
+		'--customize-hook=chroot "$1" systemctl enable systemd-networkd.service' \
+		"--customize-hook=printf \"[Match]\\n$SYSD_NET_MATCH\\n[Network]\\n$SYSD_NET_NET"'\n[DHCP]\nUseDomains=yes\n" > "$1/etc/systemd/network/20-wired.network"' \
+		"$@"
+fi
 
 # add ssh key for root
 if test -n "$SSHKEY"; then