--keep-mgmt-net

clab/clab.go

@@ -88,6 +88,12 @@ func WithRuntime(name string, d bool, dur time.Duration, gracefulShutdown bool)
 	}
 }
 
+func WithKeepMgmtNet() ClabOption {
+	return func(c *CLab) {
+		c.Runtime.WithKeepMgmtNet()
+	}
+}
+
 func WithTopoFile(file string) ClabOption {
 	return func(c *CLab) {
 		if file == "" {

cmd/destroy.go

@@ -19,8 +19,11 @@ import (
 	"github.com/srl-labs/containerlab/types"
 )
 
-var cleanup bool
-var graceful bool
+var (
+	cleanup     bool
+	graceful    bool
+	keepmgmtnet bool
+)
 
 // destroyCmd represents the destroy command
 var destroyCmd = &cobra.Command{
@@ -41,6 +44,10 @@ var destroyCmd = &cobra.Command{
 			clab.WithRuntime(rt, debug, timeout, graceful),
 		}
 
+		if keepmgmtnet {
+			opts = append(opts, clab.WithKeepMgmtNet())
+		}
+
 		topos := map[string]struct{}{}
 
 		switch {
@@ -112,6 +119,7 @@ func init() {
 	destroyCmd.Flags().BoolVarP(&graceful, "graceful", "", false, "attempt to stop containers before removing")
 	destroyCmd.Flags().BoolVarP(&all, "all", "a", false, "destroy all containerlab labs")
 	destroyCmd.Flags().UintVarP(&maxWorkers, "max-workers", "", 0, "limit the maximum number of workers deleteing nodes")
+	destroyCmd.Flags().BoolVarP(&keepmgmtnet, "keep-mgmt-net", "", false, "do not remove the mgmt network")
 }
 
 func deleteEntriesFromHostsFile(containers []types.GenericContainer, bridgeName string) error {
@@ -202,7 +210,7 @@ func destroyLab(ctx context.Context, c *clab.CLab) (err error) {
 	}
 
 	// delete lab management network
-	log.Infof("Deleting network '%s'...", c.Config.Mgmt.Network)
+	log.Infof("Cleanup networking")
 	if err = c.Runtime.DeleteNet(ctx); err != nil {
 		// do not log error message if deletion error simply says that such network doesn't exist
 		if err.Error() != fmt.Sprintf("Error: No such network: %s", c.Config.Mgmt.Network) {

cmd/root.go

@@ -32,7 +32,6 @@ var rootCmd = &cobra.Command{
 		if debug {
 			log.SetLevel(log.DebugLevel)
 		}
-
 	},
 }
 

runtime/containerd/containerd.go

@@ -39,14 +39,14 @@ const (
 func init() {
 	runtime.Register(dockerRuntimeName, func() runtime.ContainerRuntime {
 		return &ContainerdRuntime{
-			Mgmt: new(types.MgmtNet),
-		}
+			Mgmt: new(types.MgmtNet)}
 	})
 }
 
 func (c *ContainerdRuntime) Init(opts ...runtime.RuntimeOption) error {
 	var err error
 	log.Info("Runtime: containerd")
+	c.keepMgmtNet = false
 	c.client, err = containerd.New("/run/containerd/containerd.sock")
 	if err != nil {
 		return err
@@ -71,6 +71,7 @@ type ContainerdRuntime struct {
 	Mgmt             *types.MgmtNet
 	debug            bool
 	gracefulShutdown bool
+	keepMgmtNet      bool
 }
 
 func (c *ContainerdRuntime) WithConfig(cfg *runtime.RuntimeConfig) {
@@ -93,14 +94,27 @@ func (c *ContainerdRuntime) WithMgmtNet(n *types.MgmtNet) {
 	c.Mgmt = n
 }
 
+func (c *ContainerdRuntime) WithKeepMgmtNet() {
+	c.keepMgmtNet = true
+}
+
 func (c *ContainerdRuntime) CreateNet(ctx context.Context) error {
 	log.Debug("CreateNet() - Not needed with containerd")
 	return nil
 }
 func (c *ContainerdRuntime) DeleteNet(context.Context) error {
-	log.Debug("DeleteNet() - Not yet required with containerd")
-	return nil
+	bridgename := c.Mgmt.Bridge
+	brInUse, err := utils.CheckBrInUse(bridgename)
+	if c.keepMgmtNet || brInUse {
+		log.Infof("Skipping deletion of bridge '%s'", bridgename)
+		return nil
+	}
+	if err != nil {
+		return err
+	}
+	return utils.DeleteNetworkInterface(bridgename)
 }
+
 func (c *ContainerdRuntime) ContainerInspect(context.Context, string) (*types.GenericContainer, error) {
 	return nil, errors.New("not implemented")
 }

runtime/docker/docker.go

@@ -48,11 +48,13 @@ type DockerRuntime struct {
 	Mgmt             *types.MgmtNet
 	debug            bool
 	gracefulShutdown bool
+	keepMgmtNet      bool
 }
 
 func (c *DockerRuntime) Init(opts ...runtime.RuntimeOption) error {
 	var err error
 	log.Info("Runtime: Docker")
+	c.keepMgmtNet = false
 	c.Client, err = dockerC.NewClientWithOpts(dockerC.FromEnv, dockerC.WithAPIVersionNegotiation())
 	if err != nil {
 		return err
@@ -63,6 +65,10 @@ func (c *DockerRuntime) Init(opts ...runtime.RuntimeOption) error {
 	return nil
 }
 
+func (c *DockerRuntime) WithKeepMgmtNet() {
+	c.keepMgmtNet = true
+}
+
 func (c *DockerRuntime) WithConfig(cfg *runtime.RuntimeConfig) {
 	c.timeout = cfg.Timeout
 	c.debug = cfg.Debug
@@ -183,28 +189,29 @@ func (c *DockerRuntime) CreateNet(ctx context.Context) (err error) {
 
 // DeleteNet deletes a docker bridge
 func (c *DockerRuntime) DeleteNet(ctx context.Context) (err error) {
-	if c.Mgmt.Network == "bridge" {
-		log.Debug("Skipping potential deletion of docker default bridge 'bridge'.")
+	network := c.Mgmt.Network
+	if network == "bridge" || c.keepMgmtNet {
+		log.Infof("Skipping potential deletion of docker default bridge '%s'", network)
 		return nil
 	}
 	nctx, cancel := context.WithTimeout(ctx, c.timeout)
 	defer cancel()
 
-	nres, err := c.Client.NetworkInspect(ctx, c.Mgmt.Network, dockerTypes.NetworkInspectOptions{})
+	nres, err := c.Client.NetworkInspect(ctx, network, dockerTypes.NetworkInspectOptions{})
 	if err != nil {
 		return err
 	}
 	numEndpoints := len(nres.Containers)
 	if numEndpoints > 0 {
 		if c.debug {
-			log.Debugf("network '%s' has %d active endpoints, deletion skipped", c.Mgmt.Network, numEndpoints)
+			log.Debugf("network '%s' has %d active endpoints, deletion skipped", network, numEndpoints)
 			for _, endp := range nres.Containers {
-				log.Debugf("'%s' is connected to %s", endp.Name, c.Mgmt.Network)
+				log.Debugf("'%s' is connected to %s", endp.Name, network)
 			}
 		}
 		return nil
 	}
-	err = c.Client.NetworkRemove(nctx, c.Mgmt.Network)
+	err = c.Client.NetworkRemove(nctx, network)
 	if err != nil {
 		return err
 	}

runtime/runtime.go

@@ -23,6 +23,8 @@ type ContainerRuntime interface {
 	WithConfig(*RuntimeConfig)
 	// Set the network management details (generated by the config.go)
 	WithMgmtNet(*types.MgmtNet)
+	// Instructs the runtime not to delete the mgmt network on destroy
+	WithKeepMgmtNet()
 	// Create container (bridge) network
 	CreateNet(context.Context) error
 	// Delete container (bridge) network
@@ -57,6 +59,7 @@ type RuntimeConfig struct {
 	Timeout          time.Duration
 	GracefulShutdown bool
 	Debug            bool
+	KeepMgmtNet      bool
 }
 
 var ContainerRuntimes = map[string]Initializer{}
@@ -76,3 +79,9 @@ func WithMgmtNet(mgmt *types.MgmtNet) RuntimeOption {
 		r.WithMgmtNet(mgmt)
 	}
 }
+
+func WithKeepMgmtNet() RuntimeOption {
+	return func(r ContainerRuntime) {
+		r.WithKeepMgmtNet()
+	}
+}

utils/netlink.go

@@ -47,3 +47,31 @@ func DefaultNetMTU() (string, error) {
 	}
 	return fmt.Sprint(b.MTU), nil
 }
+
+func CheckBrInUse(brname string) (bool, error) {
+	InUse := false
+	l, err := netlink.LinkList()
+	if err != nil {
+		return InUse, err
+	}
+	mgmtbr, err := netlink.LinkByName(brname)
+	if err != nil {
+		return InUse, err
+	}
+	mgmtbridx := mgmtbr.Attrs().Index
+	for _, link := range l {
+		if link.Attrs().MasterIndex == mgmtbridx {
+			InUse = true
+			break
+		}
+	}
+	return InUse, nil
+}
+
+func DeleteNetworkInterface(name string) error {
+	l, err := netlink.LinkByName(name)
+	if err != nil {
+		return err
+	}
+	return netlink.LinkDel(l)
+}