From 89e2e4fb0a6b011fb87512968ab821a6b55a1d69 Mon Sep 17 00:00:00 2001
From: "David M. Johnson" <johnsond@flux.utah.edu>
Date: Sun, 16 Mar 2025 12:57:42 -0600
Subject: [PATCH] Better coexistence for xenbridge-setup and
systemd-{networkd,resolved}.
In this commit, we actually write the proper configuration to systemd-networkd
files instead of stopping systemd entirely. Moreover, we grab the nameserver
configuration from systemd-resolved if the stub resolver is in use, and migrate
it to the xenbr. All in the name of upstream compat/coexistence and avoiding
special hacks.
---
clientside/tmcc/linux/xen/xenbridge-setup | 74 ++++++++++++++++++-----
1 file changed, 58 insertions(+), 16 deletions(-)
diff --git a/clientside/tmcc/linux/xen/xenbridge-setup b/clientside/tmcc/linux/xen/xenbridge-setup
index 26cc76dbb2..6f530ab9c4 100644
--- a/clientside/tmcc/linux/xen/xenbridge-setup
+++ b/clientside/tmcc/linux/xen/xenbridge-setup
@@ -1,6 +1,6 @@
#!/usr/bin/perl -w
#
-# Copyright (c) 2012-2018 University of Utah and the Flux Group.
+# Copyright (c) 2012-2025 University of Utah and the Flux Group.
#
# {{{EMULAB-LICENSE
#
@@ -234,25 +234,67 @@ if ($iscontrol) {
}
#
-# If this node is running systemd-networkd, kill its configuration and
-# stop systemd-networkd if it's not managing any other interfaces.
-# Otherwise, systemd-networkd will keep trying to DHCP on the control
-# net interface.
+# If this node is running systemd-networkd, move its configuration to xenbr0.
#
if (-e "/var/run/systemd/network/${interface}.network") {
- unlink("/var/run/systemd/network/${interface}.network");
- my $network_file_count = 0;
+ open(NETF,"/var/run/systemd/network/${interface}.network");
+ open(XNETF,">/var/run/systemd/network/${XENBR}.network");
+ while (my $line = <NETF>) {
+ $line =~ "s/${interface}/${XENBR}/g";
+ print XNETF $line;
+ }
+ close(NETF);
+ close(XNETF);
- foreach my $d ("/var/run/systemd/network","/etc/systemd/network") {
- if (-d $d && opendir(my $dh,$d) == 0) {
- $network_file_count += grep { /\.network\$/ } readdir($dh);
- closedir($dh);
- }
+ my @lines = (
+ "[NetDev]\n",
+ "Name=${XENBR}\n",
+ "Kind=bridge\n"
+ );
+ open(XNETDF,">/var/run/systemd/network/${XENBR}.netdev");
+ foreach my $line (@lines) {
+ print XNETDF $line;
}
- if ($network_file_count > 0) {
- system("systemctl restart systemd-networkd &");
+ close(XNETDF);
+
+ @lines = (
+ "[Match]\n",
+ "Name=${interface}\n",
+ "\n",
+ "[Network]\n",
+ "Bridge=$XENBR\n"
+ );
+ open(NETF,">/var/run/systemd/network/${interface}.network");
+ foreach my $line (@lines) {
+ print NETF $line;
}
- else {
- system("systemctl stop systemd-networkd");
+ close(NETF);
+
+ #
+ # If DNS is controlled by systemd-resolved, we have to migrate its
+ # configuration.
+ #
+ if (-l "/etc/resolv.conf") {
+ my $link = readlink("/etc/resolv.conf");
+ if ($link =~ /stub-resolv/) {
+ my $dns = `resolvectl dns ${interface} | cut -d: -f2`;
+ chomp $dns;
+ my $domain = `resolvectl domain ${interface} | cut -d: -f2`;
+ chomp $domain;
+ if ($dns) {
+ print "xenbridge-setup: Updating systemd-resolved dns for $XENBR to '$dns'\n";
+ system("resolvectl dns ${XENBR} $dns");
+ } else {
+ print STDERR "Failed to find DNS for ${interface} via resolvectl\n";
+ }
+ if ($domain) {
+ print "xenbridge-setup: Updating systemd-resolved domain for $XENBR to '$domain'\n";
+ system("resolvectl domain ${XENBR} $domain");
+ } else {
+ print STDERR "Failed to find DNS domain for ${interface} via resolvectl\n";
+ }
+ }
}
+
+ #system("systemctl restart systemd-networkd &");
}
--
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