bonding: Add support for probing the bonding module with parameters

Until support for bonding params is added to networkd, this will be
neccessary in order to use bonding parameters (i.e. miimon, mode).
This also makes it such that the 8012q module will only be loaded if
the network config makes use of VLANs.

system/networkd.go

@@ -6,6 +6,7 @@ import (
 	"net"
 	"os/exec"
 	"path"
+	"strings"
 
 	"github.com/coreos/coreos-cloudinit/network"
 	"github.com/coreos/coreos-cloudinit/third_party/github.com/dotcloud/docker/pkg/netlink"
@@ -26,10 +27,10 @@ func RestartNetwork(interfaces []network.InterfaceGenerator) (err error) {
 		return
 	}
 
-	if err = probe8012q(); err != nil {
+	if err = maybeProbe8012q(interfaces); err != nil {
 		return
 	}
-	return
+	return maybeProbeBonding(interfaces)
 }
 
 func downNetworkInterfaces(interfaces []network.InterfaceGenerator) error {
@@ -55,8 +56,24 @@ func downNetworkInterfaces(interfaces []network.InterfaceGenerator) error {
 	return nil
 }
 
-func probe8012q() error {
-	return exec.Command("modprobe", "8021q").Run()
+func maybeProbe8012q(interfaces []network.InterfaceGenerator) error {
+	for _, iface := range interfaces {
+		if iface.Type() == "vlan" {
+			return exec.Command("modprobe", "8021q").Run()
+		}
+	}
+	return nil
+}
+
+func maybeProbeBonding(interfaces []network.InterfaceGenerator) error {
+	args := []string{"bonding"}
+	for _, iface := range interfaces {
+		if iface.Type() == "bond" {
+			args = append(args, strings.Split(iface.ModprobeParams(), " ")...)
+			break
+		}
+	}
+	return exec.Command("modprobe", args...).Run()
 }
 
 func restartNetworkd() error {