From dabeff277774190d047155be6566da184b2b3e8f Mon Sep 17 00:00:00 2001 From: Christian Breunig Date: Fri, 7 Aug 2026 20:59:54 +0000 Subject: container: T7736: disable IPv6 DAD for netavark bridges to fix aardvark-dns race netavark assigns the IPv6 gateway address to a container "pod-*" bridge and immediately invokes aardvark-dns to bind its DNS listener to it. While the address is "tentative" during Duplicate Address Detection, that bind() fails with EADDRNOTAVAIL and container startup fails for any IPv6-enabled network. The kernel only skips DAD for an address if both "all" and the specific interface's own accept_dad are disabled at the moment the interface is created. A per-interface override is always either too late for a network's first-ever container - as the network can only be created in-time and not explicitly before starting the first container. --- smoketest/scripts/cli/test_system_ipv6.py | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'smoketest/scripts/cli') diff --git a/smoketest/scripts/cli/test_system_ipv6.py b/smoketest/scripts/cli/test_system_ipv6.py index d7282c4c8..a501c6862 100755 --- a/smoketest/scripts/cli/test_system_ipv6.py +++ b/smoketest/scripts/cli/test_system_ipv6.py @@ -56,8 +56,12 @@ class TestSystemIPv6(VyOSUnitTestSHIM.TestCase): self.assertNotIn('no ipv6 forwarding', frrconfig) def test_system_ipv6_strict_dad(self): - # This defaults to 1 - self.assertEqual(sysctl_read(['net', 'ipv6', 'conf', 'all', 'accept_dad']), '1') + # T7736: "all" defaults to 0 (see 32-vyos-podman.conf) so that + # newly created interfaces outside VyOS's interface model (e.g. + # netavark's container bridges) skip DAD; VyOS-managed interface + # types always write their own explicit accept_dad on commit + # (XML defaultValue 1), so this does not affect them. + self.assertEqual(sysctl_read(['net', 'ipv6', 'conf', 'all', 'accept_dad']), '0') # Do not assign any IPv6 address on interfaces, this requires a reboot # which cannot be tested, but we can read the config file :) -- cgit v1.2.3