append podman dns search domain

Append the podman dns seach domain to the host search domains when we
use the dnsname/aardvark server. Previously it would only use podman
seach domains and discard the host domains.

Fixes containers#13103

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

libpod/container_internal_linux.go

@@ -2099,38 +2099,38 @@ func (c *Container) generateResolvConf() (string, error) {
 	}
 	dnsServers := append(dns, c.config.DNSServer...)
 	// If the user provided dns, it trumps all; then dns masq; then resolv.conf
+	var search []string
 	switch {
 	case len(dnsServers) > 0:
-
 		// We store DNS servers as net.IP, so need to convert to string
 		for _, server := range dnsServers {
 			nameservers = append(nameservers, server.String())
 		}
-	case len(networkNameServers) > 0:
-		nameservers = append(nameservers, networkNameServers...)
 	default:
 		// Make a new resolv.conf
-		nameservers = resolvconf.GetNameservers(resolv.Content)
-		// slirp4netns has a built in DNS server.
+		// first add the nameservers from the networks status
+		nameservers = append(nameservers, networkNameServers...)
+		// when we add network dns server we also have to add the search domains
+		search = networkSearchDomains
+		// slirp4netns has a built in DNS forwarder.
 		if c.config.NetMode.IsSlirp4netns() {
 			slirp4netnsDNS, err := GetSlirp4netnsDNS(c.slirp4netnsSubnet)
 			if err != nil {
 				logrus.Warn("Failed to determine Slirp4netns DNS: ", err.Error())
 			} else {
-				nameservers = append([]string{slirp4netnsDNS.String()}, nameservers...)
+				nameservers = append(nameservers, slirp4netnsDNS.String())
 			}
 		}
+		nameservers = append(nameservers, resolvconf.GetNameservers(resolv.Content)...)
 	}
 
-	var search []string
-	if len(c.config.DNSSearch) > 0 || len(c.runtime.config.Containers.DNSSearches) > 0 || len(networkSearchDomains) > 0 {
+	if len(c.config.DNSSearch) > 0 || len(c.runtime.config.Containers.DNSSearches) > 0 {
 		if !util.StringInSlice(".", c.config.DNSSearch) {
-			search = c.runtime.config.Containers.DNSSearches
+			search = append(search, c.runtime.config.Containers.DNSSearches...)
 			search = append(search, c.config.DNSSearch...)
-			search = append(search, networkSearchDomains...)
 		}
 	} else {
-		search = resolvconf.GetSearchDomains(resolv.Content)
+		search = append(search, resolvconf.GetSearchDomains(resolv.Content)...)
 	}
 
 	var options []string

test/system/500-networking.bats

@@ -605,9 +605,27 @@ load helpers
     "8.8.8.8",
 ]
 EOF
-    CONTAINERS_CONF=$containersconf run_podman run --rm $IMAGE grep "example.com" /etc/resolv.conf
-    CONTAINERS_CONF=$containersconf run_podman run --rm $IMAGE grep $searchIP /etc/resolv.conf
-    is "$output" "nameserver $searchIP" "Should only be one $searchIP not multiple"
+
+    local nl="
+"
+
+    CONTAINERS_CONF=$containersconf run_podman run --rm $IMAGE cat /etc/resolv.conf
+    is "$output" "search example.com$nl.*" "correct seach domain"
+    is "$output" ".*nameserver 1.1.1.1${nl}nameserver $searchIP${nl}nameserver 1.0.0.1${nl}nameserver 8.8.8.8" "nameserver order is correct"
+
+    # create network with dns
+    local netname=testnet-$(random_string 10)
+    local subnet=$(random_rfc1918_subnet)
+    run_podman network create --subnet "$subnet.0/24"  $netname
+    # custom server overwrites the network dns server
+    CONTAINERS_CONF=$containersconf run_podman run --network $netname --rm $IMAGE cat /etc/resolv.conf
+    is "$output" "search example.com$nl.*" "correct seach domain"
+    is "$output" ".*nameserver 1.1.1.1${nl}nameserver $searchIP${nl}nameserver 1.0.0.1${nl}nameserver 8.8.8.8" "nameserver order is correct"
+
+    # we should use the integrated dns server
+    run_podman run --network $netname --rm $IMAGE cat /etc/resolv.conf
+    is "$output" "search dns.podman.*" "correct seach domain"
+    is "$output" ".*nameserver $subnet.1.*" "integrated dns nameserver is set"
 }
 
 # vim: filetype=sh