I would rather invert this, and define 'no-dns-fallback', off by default.
Alex
On Wed, 7 Sept 2022 at 09:12, niko.mauno@... via
lists.openembedded.org <niko.mauno=vaisala.com@...>
wrote:

systemd defines a default set of fallback DNS servers in
https://github.com/systemd/systemd/blob/v251/meson_options.txt#L328-L330

By adding a PACKAGECONFIG knob providing a convenient way to opt out,
and then removing that value from systemd's PACKAGECONFIG, the output
from runtime 'resolvectl status' command no longer contains the
following line:

Fallback DNS Servers: 1.1.1.1#cloudflare-dns.com 8.8.8.8#dns.google 1.0.0.1#cloudflare-dns.com 8.8.4.4#dns.google 2606:4700:4700::1111#cloudflare-dns.com 2001:4860:4860::8888#dns.google 2606:4700:4700::1001#cloudflare-dns.com 2001:4860:4860::8844#dns.google

Signed-off-by: Niko Mauno <niko.mauno@...>
---
meta/recipes-core/systemd/systemd_251.4.bb | 2 ++
1 file changed, 2 insertions(+)

diff --git a/meta/recipes-core/systemd/systemd_251.4.bb b/meta/recipes-core/systemd/systemd_251.4.bb
index 8497e24af9..0f30b7dbb3 100644
--- a/meta/recipes-core/systemd/systemd_251.4.bb
+++ b/meta/recipes-core/systemd/systemd_251.4.bb
@@ -64,6 +64,7 @@ PACKAGECONFIG ??= " \
${@bb.utils.contains('DISTRO_FEATURES', 'sysvinit', '', 'link-udev-shared', d)} \
backlight \
binfmt \
+ default-dns-fallback \
gshadow \
hibernate \
hostnamed \
@@ -129,6 +130,7 @@ PACKAGECONFIG[coredump] = "-Dcoredump=true,-Dcoredump=false"
PACKAGECONFIG[cryptsetup] = "-Dlibcryptsetup=true,-Dlibcryptsetup=false,cryptsetup,,cryptsetup"
PACKAGECONFIG[tpm2] = "-Dtpm2=true,-Dtpm2=false,tpm2-tss,tpm2-tss libtss2 libtss2-tcti-device"
PACKAGECONFIG[dbus] = "-Ddbus=true,-Ddbus=false,dbus"
+PACKAGECONFIG[default-dns-fallback] = ",-Ddns-servers="
PACKAGECONFIG[efi] = "-Defi=true,-Defi=false"
PACKAGECONFIG[gnu-efi] = "-Dgnu-efi=true -Defi-libdir=${STAGING_LIBDIR} -Defi-includedir=${STAGING_INCDIR}/efi,-Dgnu-efi=false,gnu-efi"
PACKAGECONFIG[elfutils] = "-Delfutils=true,-Delfutils=false,elfutils"
--
2.35.1