netavark: macvlan networks keep custom nameservers

The change to use the custom dns server in aardvark-dns caused a
regression here because macvlan networks never returned the nameservers
in netavark and it also does not make sense to do so.

Instead check here if we got any network nameservers, if not we then use
the ones from the config if set otherwise fallback to host servers.

Fixes containers#19169

Signed-off-by: Paul Holzinger <[email protected]>

libpod/container_internal_common.go

@@ -2077,12 +2077,12 @@ func (c *Container) addResolvConf() error {
 
 	// If NetworkBackend is `netavark` do not populate `/etc/resolv.conf`
 	// with custom dns server since after https://github.com/containers/netavark/pull/452
-	// netavark will always set required `nameservers` in statsBlock and libpod
+	// netavark will always set required `nameservers` in StatusBlock and libpod
 	// will correctly populate `networkNameServers`. Also see https://github.com/containers/podman/issues/16172
 
 	// Exception: Populate `/etc/resolv.conf` if container is not connected to any network
-	// ( i.e len(netStatus)==0 ) since in such case netavark is not invoked at all.
-	if networkBackend != string(types.Netavark) || len(netStatus) == 0 {
+	// with dns enabled then we do not get any nameservers back.
+	if networkBackend != string(types.Netavark) || len(networkNameServers) == 0 {
 		nameservers = append(nameservers, c.runtime.config.Containers.DNSServers...)
 		for _, ip := range c.config.DNSServer {
 			nameservers = append(nameservers, ip.String())

test/e2e/run_networking_test.go

@@ -1186,4 +1186,21 @@ EXPOSE 2004-2005/tcp`, ALPINE)
 		Expect(session).Should(Exit(0))
 		Expect(session.OutputToStringArray()).To(HaveLen(4), "output should only show link local address")
 	})
+
+	It("podman run with macvlan network", func() {
+		net := "mv-" + stringid.GenerateRandomID()
+		session := podmanTest.Podman([]string{"network", "create", "-d", "macvlan", "--subnet", "10.10.0.0/24", net})
+		session.WaitWithDefaultTimeout()
+		defer podmanTest.removeNetwork(net)
+		Expect(session).Should(Exit(0))
+
+		// use options and search to make sure we get the same resolv.conf everywhere
+		run := podmanTest.Podman([]string{"run", "--network", net, "--dns", "127.0.0.128",
+			"--dns-option", "ndots:1", "--dns-search", ".", ALPINE, "cat", "/etc/resolv.conf"})
+		run.WaitWithDefaultTimeout()
+		Expect(run).Should(Exit(0))
+		Expect(string(run.Out.Contents())).To(Equal(`nameserver 127.0.0.128
+options ndots:1
+`))
+	})
 })