[Proposal] Implement namespacing for networks

cmd/nerdctl/completion.go

@@ -109,7 +109,7 @@ func shellCompleteNetworkNames(cmd *cobra.Command, exclude []string) ([]string,
 		excludeMap[ex] = struct{}{}
 	}
 
-	e, err := netutil.NewCNIEnv(globalOptions.CNIPath, globalOptions.CNINetConfPath)
+	e, err := netutil.NewCNIEnv(globalOptions.CNIPath, globalOptions.CNINetConfPath, netutil.WithNamespace(globalOptions.Namespace))
 	if err != nil {
 		return nil, cobra.ShellCompDirectiveError
 	}

cmd/nerdctl/network_inspect_test.go

@@ -66,3 +66,28 @@ func TestNetworkInspect(t *testing.T) {
 	}
 	assert.DeepEqual(base.T, expectedIPAM, got.IPAM)
 }
+
+func TestNetworkWithNamespace(t *testing.T) {
+	testutil.DockerIncompatible(t)
+
+	t.Parallel()
+
+	tID := testutil.Identifier(t)
+	base := testutil.NewBase(t)
+	baseOther := testutil.NewBaseWithNamespace(t, tID)
+
+	tearDown := func() {
+		base.Cmd("network", "rm", tID).Run()
+		baseOther.Cmd("namespace", "remove", tID).Run()
+	}
+	tearDown()
+	t.Cleanup(tearDown)
+
+	base.Cmd("network", "create", tID).AssertOK()
+
+	// Other namespace cannot inspect, prune, see, or remove this network
+	baseOther.Cmd("network", "inspect", tID).AssertFail()
+	baseOther.Cmd("network", "prune", "-f").AssertOutNotContains(tID)
+	baseOther.Cmd("network", "ls").AssertOutNotContains(tID)
+	baseOther.Cmd("network", "remove", tID).AssertFail()
+}

cmd/nerdctl/network_remove_linux_test.go

@@ -25,30 +25,6 @@ import (
 	"gotest.tools/v3/assert"
 )
 
-func TestNetworkRemoveInOtherNamespace(t *testing.T) {
-	if rootlessutil.IsRootless() {
-		t.Skip("test skipped for remove rootless network")
-	}
-	if testutil.GetTarget() == testutil.Docker {
-		t.Skip("test skipped for docker")
-	}
-	// --namespace=nerdctl-test
-	base := testutil.NewBase(t)
-	// --namespace=nerdctl-other
-	baseOther := testutil.NewBaseWithNamespace(t, "nerdctl-other")
-	networkName := testutil.Identifier(t)
-
-	base.Cmd("network", "create", networkName).AssertOK()
-	defer base.Cmd("network", "rm", networkName).AssertOK()
-
-	tID := testutil.Identifier(t)
-	base.Cmd("run", "-d", "--net", networkName, "--name", tID, testutil.AlpineImage, "sleep", "infinity").AssertOK()
-	defer base.Cmd("rm", "-f", tID).Run()
-
-	// delete network in namespace nerdctl-other
-	baseOther.Cmd("network", "rm", networkName).AssertFail()
-}
-
 func TestNetworkRemove(t *testing.T) {
 	if rootlessutil.IsRootless() {
 		t.Skip("test skipped for remove rootless network")

docs/cni.md

@@ -116,7 +116,16 @@ For example:
 ## Custom networks
 
 You can also customize your CNI network by providing configuration files.
-For example you have one configuration file(`/etc/cni/net.d/10-mynet.conf`)
+
+When rootful, the expected root location is `/etc/cni/net.d`.
+For rootless, the expected root location is `~/.config/cni/net.d/`
+
+Configuration files (like `10-mynet.conf`) can be placed either in the root location,
+or under a subfolder.
+If in the root location, this network will be available to all nerdctl namespaces.
+If placed in a subfolder, it will be available only to the identically named namespace.
+
+For example, you have one configuration file(`/etc/cni/net.d/10-mynet.conf`)
 for `bridge` network:
 
 ```json
@@ -138,7 +147,7 @@ for `bridge` network:
 ```
 
 This will configure a new CNI network with the name `mynet`, and you can use
-this network to create a container:
+this network to create a container in any namespace:
 
 ```console
 # nerdctl run -it --net mynet --rm alpine ip addr show

docs/dir.md

@@ -65,5 +65,9 @@ Data volume
 
 Can be overridden with `nerdctl --cni-netconfpath=<NETCONFPATH>` flag and environment variable `$NETCONFPATH`.
 
+At the top-level of <NETCONFPATH>, network (files) are shared accross all namespaces.
+Sub-folders inside <NETCONFPATH> are only available to the namespace bearing the same name,
+and its networks definitions are private.
+
 Files:
 - `nerdctl-<NWNAME>.conflist`: CNI conf list created by nerdctl

pkg/cmd/compose/compose.go

@@ -41,7 +41,7 @@ import (
 
 // New returns a new *composer.Composer.
 func New(client *containerd.Client, globalOptions types.GlobalCommandOptions, options composer.Options, stdout, stderr io.Writer) (*composer.Composer, error) {
-	cniEnv, err := netutil.NewCNIEnv(globalOptions.CNIPath, globalOptions.CNINetConfPath, netutil.WithDefaultNetwork())
+	cniEnv, err := netutil.NewCNIEnv(globalOptions.CNIPath, globalOptions.CNINetConfPath, netutil.WithNamespace(globalOptions.Namespace), netutil.WithDefaultNetwork())
 	if err != nil {
 		return nil, err
 	}

pkg/cmd/container/kill.go

@@ -152,7 +152,7 @@ func cleanupNetwork(ctx context.Context, container containerd.Container, globalO
 		case nettype.Host, nettype.None, nettype.Container:
 			// NOP
 		case nettype.CNI:
-			e, err := netutil.NewCNIEnv(globalOpts.CNIPath, globalOpts.CNINetConfPath, netutil.WithDefaultNetwork())
+			e, err := netutil.NewCNIEnv(globalOpts.CNIPath, globalOpts.CNINetConfPath, netutil.WithNamespace(globalOpts.Namespace), netutil.WithDefaultNetwork())
 			if err != nil {
 				return err
 			}

pkg/cmd/network/create.go

@@ -33,7 +33,7 @@ func Create(options types.NetworkCreateOptions, stdout io.Writer) error {
 		options.Subnets = []string{""}
 	}
 
-	e, err := netutil.NewCNIEnv(options.GOptions.CNIPath, options.GOptions.CNINetConfPath)
+	e, err := netutil.NewCNIEnv(options.GOptions.CNIPath, options.GOptions.CNINetConfPath, netutil.WithNamespace(options.GOptions.Namespace))
 	if err != nil {
 		return err
 	}

pkg/cmd/network/inspect.go

@@ -32,7 +32,7 @@ import (
 
 func Inspect(ctx context.Context, options types.NetworkInspectOptions) error {
 	globalOptions := options.GOptions
-	e, err := netutil.NewCNIEnv(globalOptions.CNIPath, globalOptions.CNINetConfPath)
+	e, err := netutil.NewCNIEnv(globalOptions.CNIPath, globalOptions.CNINetConfPath, netutil.WithNamespace(options.GOptions.Namespace))
 
 	if err != nil {
 		return err

pkg/cmd/network/list.go

@@ -65,7 +65,7 @@ func List(ctx context.Context, options types.NetworkListOptions) error {
 		}
 	}
 
-	e, err := netutil.NewCNIEnv(globalOptions.CNIPath, globalOptions.CNINetConfPath)
+	e, err := netutil.NewCNIEnv(globalOptions.CNIPath, globalOptions.CNINetConfPath, netutil.WithNamespace(options.GOptions.Namespace))
 	if err != nil {
 		return err
 	}

pkg/cmd/network/prune.go

@@ -28,7 +28,7 @@ import (
 )
 
 func Prune(ctx context.Context, client *containerd.Client, options types.NetworkPruneOptions) error {
-	e, err := netutil.NewCNIEnv(options.GOptions.CNIPath, options.GOptions.CNINetConfPath)
+	e, err := netutil.NewCNIEnv(options.GOptions.CNIPath, options.GOptions.CNINetConfPath, netutil.WithNamespace(options.GOptions.Namespace))
 	if err != nil {
 		return err
 	}

pkg/cmd/network/remove.go

@@ -27,7 +27,7 @@ import (
 )
 
 func Remove(ctx context.Context, client *containerd.Client, options types.NetworkRemoveOptions) error {
-	e, err := netutil.NewCNIEnv(options.GOptions.CNIPath, options.GOptions.CNINetConfPath)
+	e, err := netutil.NewCNIEnv(options.GOptions.CNIPath, options.GOptions.CNINetConfPath, netutil.WithNamespace(options.GOptions.Namespace))
 	if err != nil {
 		return err
 	}

pkg/containerutil/container_network_manager_linux.go

@@ -39,7 +39,7 @@ type cniNetworkManagerPlatform struct {
 
 // Verifies that the internal network settings are correct.
 func (m *cniNetworkManager) VerifyNetworkOptions(_ context.Context) error {
-	e, err := netutil.NewCNIEnv(m.globalOptions.CNIPath, m.globalOptions.CNINetConfPath, netutil.WithDefaultNetwork())
+	e, err := netutil.NewCNIEnv(m.globalOptions.CNIPath, m.globalOptions.CNINetConfPath, netutil.WithNamespace(m.globalOptions.Namespace), netutil.WithDefaultNetwork())
 	if err != nil {
 		return err
 	}

pkg/containerutil/container_network_manager_windows.go

@@ -36,7 +36,7 @@ type cniNetworkManagerPlatform struct {
 
 // Verifies that the internal network settings are correct.
 func (m *cniNetworkManager) VerifyNetworkOptions(_ context.Context) error {
-	e, err := netutil.NewCNIEnv(m.globalOptions.CNIPath, m.globalOptions.CNINetConfPath, netutil.WithDefaultNetwork())
+	e, err := netutil.NewCNIEnv(m.globalOptions.CNIPath, m.globalOptions.CNINetConfPath, netutil.WithNamespace(m.globalOptions.Namespace), netutil.WithDefaultNetwork())
 	if err != nil {
 		return err
 	}
@@ -67,7 +67,7 @@ func (m *cniNetworkManager) VerifyNetworkOptions(_ context.Context) error {
 }
 
 func (m *cniNetworkManager) getCNI() (gocni.CNI, error) {
-	e, err := netutil.NewCNIEnv(m.globalOptions.CNIPath, m.globalOptions.CNINetConfPath, netutil.WithDefaultNetwork())
+	e, err := netutil.NewCNIEnv(m.globalOptions.CNIPath, m.globalOptions.CNINetConfPath, netutil.WithNamespace(m.globalOptions.Namespace), netutil.WithDefaultNetwork())
 	if err != nil {
 		return nil, fmt.Errorf("failed to instantiate CNI env: %s", err)
 	}

pkg/netutil/netutil.go

@@ -46,6 +46,7 @@ import (
 type CNIEnv struct {
 	Path        string
 	NetconfPath string
+	Namespace   string
 }
 
 type CNIEnvOpt func(e *CNIEnv) error
@@ -132,6 +133,16 @@ func WithDefaultNetwork() CNIEnvOpt {
 	}
 }
 
+func WithNamespace(namespace string) CNIEnvOpt {
+	return func(e *CNIEnv) error {
+		if err := os.MkdirAll(filepath.Join(e.NetconfPath, namespace), 0755); err != nil {
+			return err
+		}
+		e.Namespace = namespace
+		return nil
+	}
+}
+
 func NewCNIEnv(cniPath, cniConfPath string, opts ...CNIEnvOpt) (*CNIEnv, error) {
 	e := CNIEnv{
 		Path:        cniPath,
@@ -193,7 +204,10 @@ func (e *CNIEnv) FilterNetworks(filterf func(*NetworkConfig) bool) ([]*NetworkCo
 }
 
 func (e *CNIEnv) getConfigPathForNetworkName(netName string) string {
-	return filepath.Join(e.NetconfPath, "nerdctl-"+netName+".conflist")
+	if netName == DefaultNetworkName || e.Namespace == "" {
+		return filepath.Join(e.NetconfPath, "nerdctl-"+netName+".conflist")
+	}
+	return filepath.Join(e.NetconfPath, e.Namespace, "nerdctl-"+netName+".conflist")
 }
 
 func (e *CNIEnv) usedSubnets() ([]*net.IPNet, error) {
@@ -404,10 +418,18 @@ func (e *CNIEnv) writeNetworkConfig(net *NetworkConfig) error {
 // networkConfigList loads config from dir if dir exists.
 func (e *CNIEnv) networkConfigList() ([]*NetworkConfig, error) {
 	l := []*NetworkConfig{}
-	fileNames, err := libcni.ConfFiles(e.NetconfPath, []string{".conf", ".conflist", ".json"})
+	common, err := libcni.ConfFiles(e.NetconfPath, []string{".conf", ".conflist", ".json"})
 	if err != nil {
 		return nil, err
 	}
+	namespaced := []string{}
+	if e.Namespace != "" {
+		namespaced, err = libcni.ConfFiles(filepath.Join(e.NetconfPath, e.Namespace), []string{".conf", ".conflist", ".json"})
+		if err != nil {
+			return nil, err
+		}
+	}
+	fileNames := append(common, namespaced...)
 	sort.Strings(fileNames)
 	for _, fileName := range fileNames {
 		var lcl *libcni.NetworkConfigList

pkg/ocihook/ocihook.go

@@ -152,7 +152,7 @@ func newHandlerOpts(state *specs.State, dataStore, cniPath, cniNetconfPath strin
 	case nettype.Host, nettype.None, nettype.Container:
 		// NOP
 	case nettype.CNI:
-		e, err := netutil.NewCNIEnv(cniPath, cniNetconfPath, netutil.WithDefaultNetwork())
+		e, err := netutil.NewCNIEnv(cniPath, cniNetconfPath, netutil.WithNamespace(namespace), netutil.WithDefaultNetwork())
 		if err != nil {
 			return nil, err
 		}