podman: switch from CNI to netavark as sole network backend

Podman's vendored containers/common library removed CNI support
entirely in commit 8d1f636e40 (March 2026). The NetworkBackend()
function now unconditionally rejects any backend other than netavark,
making network_backend = "cni" in containers.conf a runtime error.

The vpdmn rootfs originally used CNI because netavark's dependency
chain (nmap -> libpcap -> bluez5 -> cairo) was too heavy for the
vruntime BBMASK environment. That dependency chain no longer exists
— netavark v1.16.0+ uses a built-in Rust connection tester and has
no heavyweight runtime dependencies.

Recipe changes:
- Clear BUILDTAGS_EXTRA default (was CNI build tag, now a no-op)
- Set VIRTUAL-RUNTIME_container_networking and _container_dns with
  strong assignments so podman always RDEPENDS on netavark and
  aardvark-dns regardless of distro config
- Remove ${sysconfdir}/cni from FILES

vpdmn rootfs changes:
- Replace cni with netavark + aardvark-dns in IMAGE_INSTALL
- Update containers.conf network_backend from cni to netavark

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/conf/distro/include/meta-virt-container-podman.inc b/conf/distro/include/meta-virt-container-podman.inc
index b57eaaca..96ea7d7b 100644
--- a/conf/distro/include/meta-virt-container-podman.inc
+++ b/conf/distro/include/meta-virt-container-podman.inc
@@ -2,6 +2,8 @@ include meta-virt-container.inc
 
 VIRTUAL-RUNTIME_container_engine ?= "podman"
 VIRTUAL-RUNTIME_container_runtime ?= "crun"
+# netavark is the only supported network backend since podman 6.0
+# (containers/common removed CNI support entirely)
 VIRTUAL-RUNTIME_container_networking ?= "netavark"
 VIRTUAL-RUNTIME_container_dns ?= "aardvark-dns"
 VIRTUAL-RUNTIME_container_orchestration ?= ""