Package: libvirt
Version: 3.0.0-4
Severity: normal
Hi libvirt Maintainers,
Debian has been carrying the patch
"debian/Don-t-enable-default-network-on-boot.patch" for years now
and I agree that unconditionally enabling default networking
is too much messing with a user installation/network config.
We carry some [pre/post]inst code for quite a while now and it is
working fine. The code is actually from Serge and carried a long time
(since 2011, just as your patch is from 2008). Yet I didn't find a
bug/discussion to consider inclusion into Debian while I think it would
help there as well to fix the same issue.
Other than upstream which enables the default network unconditionally
this solution will essentially:
- autostart default network if there is no conflicting network that
will prevent it
- on upgrades keep whatever the user set as autostart config
I don't like too much that to do so, it makes some assumptions on how
libvirt works internally. For example ln -s for autostart and depending
on output of other tools e.g. ip. But, as I mentioned, it is working fine
for years now and the convenience of just having your default network
around and running after installing is really great.
Attached is a patch on top of latest libvirt git in experimental, as a
change
like this would only ever be post strech anyway I guess experimental is the
place
to push it if you consider this an improvement for Debian as well.
--
Christian Ehrhardt
Software Engineer, Ubuntu Server
Canonical Ltd
From 841a7b3b46ab338a6ed62cda41ba4e2c164175cc Mon Sep 17 00:00:00 2001
From: Serge Hallyn <[email protected]>
Date: Wed, 14 Dec 2016 12:12:54 +0100
Subject: [PATCH] Autostart default network if not colliding
On top of "debian/Don-t-enable-default-network-on-boot.patch"
which makes sure not to unconditionally enable default networking
to avoid messing with a user installation/network config this change
provides collision detection to do so.
Other than upstream which enables the default network unconditionally
this solution will essentially:
- autostart default network if there is no conflicting network that
will prevent it
- on upgrades keep whatever the user set as autostart config
The convenience of just having your default network around right after
install is really great.
Signed-off-by: Christian Ehrhardt <[email protected]>
---
debian/libvirt-daemon-system.postinst | 70 +++++++++++++++++++++++++++++++++++
debian/libvirt-daemon-system.preinst | 6 +++
2 files changed, 76 insertions(+)
diff --git a/debian/libvirt-daemon-system.postinst b/debian/libvirt-daemon-system.postinst
index b2e289c..fe196c6 100644
--- a/debian/libvirt-daemon-system.postinst
+++ b/debian/libvirt-daemon-system.postinst
@@ -67,6 +67,58 @@ add_users_groups()
fi
}
+includes_virbr0addr() {
+ viraddr="192.168.122.1"
+ a=$1
+ b=$2
+ for n in `seq 1 4`; do
+ aa=`echo $a | awk -F. '{ print $'$n' }'`
+ cc=`echo $viraddr | awk -F. '{ print $'$n' }'`
+ cmp=$((b/8))
+ if [ $cmp -ge $n ]; then
+ if [ $aa -ne $cc ]; then
+ echo "false"
+ return
+ fi
+ elif [ $((cmp+1)) -ge $n ]; then
+ # do we bother comparing partial (i.e. /25)?
+ :
+ else
+ break
+ fi
+ done
+ echo "true"
+ return
+}
+
+set_autostart()
+{
+ if [ ! -e /etc/libvirt/qemu/networks/autostart/default.xml ]; then
+ ln -s /etc/libvirt/qemu/networks/default.xml \
+ /etc/libvirt/qemu/networks/autostart/
+ fi
+}
+
+# on first install, don't set default network to autostart if we already
+# have a 192.168.122.0 network. Good for instance for nested libvirt.
+maybe_set_autostart()
+{
+ # don't autostart virbr0 if 192.168.122.1/24 already exists
+ found=0
+ for pair in `ip addr show | grep "inet\>" |awk '{ print $2 }'`; do
+ a=`echo $pair | awk -F/ '{ print $1}'`
+ m=`echo $pair | awk -F/ '{ print $2}'`
+ res=`includes_virbr0addr $a $m`
+ if [ $res = "true" ]; then
+ found=1
+ fi
+ done
+ if [ $found -eq 1 ]; then
+ return
+ fi
+ set_autostart
+}
+
add_statoverrides()
{
@@ -134,6 +186,24 @@ case "$1" in
# Force refresh of capabilties (#731815)
rm -f /var/cache/libvirt/qemu/capabilities/*.xml
+
+ # 1. On an initial package install, create the default network autostart
+ # symlink.
+ # 2. If the default.xml existed before upgrade, make sure it is
+ # recreated.
+ # This won't be a problem on most upgrades, but when upgrading from a
+ # version where the symlink came with the package, it will.
+ # 3. If upgrading from one of the bad libvirt versions which deleted the
+ # symlink wrongly, recreate it
+ EXISTED="/etc/libvirt/qemu/networks/autostart/TMP_defaultexisted"
+ if [ -z $2 ]; then
+ maybe_set_autostart
+ elif [ -e "$EXISTED" ]; then
+ # on upgrade, if default network was previously autostarted,
+ # continue to do so.
+ rm -f "$EXISTED"
+ set_autostart
+ fi
;;
abort-upgrade|abort-remove|abort-deconfigure)
diff --git a/debian/libvirt-daemon-system.preinst b/debian/libvirt-daemon-system.preinst
index 8a06ff5..9752d7e 100644
--- a/debian/libvirt-daemon-system.preinst
+++ b/debian/libvirt-daemon-system.preinst
@@ -26,6 +26,12 @@ case "$1" in
# Remove everything we know about libvirt-bin.service
deb-systemd-helper purge libvirt-bin.service >/dev/null
deb-systemd-helper unmask libvirt-bin.service >/dev/null
+ # If the default network autostart symlink existed, then note
+ # that here so we can recreate it at postinst.
+ EXISTED="/etc/libvirt/qemu/networks/autostart/TMP_defaultexisted"
+ if [ -e /etc/libvirt/qemu/networks/autostart/default.xml ]; then
+ touch "$EXISTED"
+ fi
fi
;;
--
2.7.4
