Add cgroup delete opt for ns deletion

Closes #3305

This adds an opt and a `--cgroup,-c` flag to `ctr namespaces rm` to
remove the cgroup that is commonly created with runtimes.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

cmd/ctr/commands/namespaces/namespaces.go

@@ -146,6 +146,12 @@ var removeCommand = cli.Command{
 	Usage:       "remove one or more namespaces",
 	ArgsUsage:   "<name> [<name>, ...]",
 	Description: "remove one or more namespaces. for now, the namespace must be empty",
+	Flags: []cli.Flag{
+		cli.BoolFlag{
+			Name:  "cgroup,c",
+			Usage: "delete the namespace's cgroup",
+		},
+	},
 	Action: func(context *cli.Context) error {
 		var exitErr error
 		client, ctx, cancel, err := commands.NewClient(context)
@@ -153,9 +159,11 @@ var removeCommand = cli.Command{
 			return err
 		}
 		defer cancel()
+
+		opts := deleteOpts(context)
 		namespaces := client.NamespaceService()
 		for _, target := range context.Args() {
-			if err := namespaces.Delete(ctx, target); err != nil {
+			if err := namespaces.Delete(ctx, target, opts...); err != nil {
 				if !errdefs.IsNotFound(err) {
 					if exitErr == nil {
 						exitErr = errors.Wrapf(err, "unable to delete %v", target)

cmd/ctr/commands/namespaces/namespaces_linux.go

@@ -0,0 +1,31 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package namespaces
+
+import (
+	"github.com/containerd/containerd"
+	"github.com/containerd/containerd/namespaces"
+	"github.com/urfave/cli"
+)
+
+func deleteOpts(context *cli.Context) []namespaces.DeleteOpts {
+	var opts []namespaces.DeleteOpts
+	if context.Bool("cgroup") {
+		opts = append(opts, containerd.WithNamespaceCgroupDeletion)
+	}
+	return opts
+}

cmd/ctr/commands/namespaces/namespaces_other.go

@@ -0,0 +1,28 @@
+// +build !linux
+
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package namespaces
+
+import (
+	"github.com/containerd/containerd/namespaces"
+	"github.com/urfave/cli"
+)
+
+func deleteOpts(context *cli.Context) []namespaces.DeleteOpts {
+	return nil
+}

metadata/namespaces.go

@@ -129,7 +129,15 @@ func (s *namespaceStore) List(ctx context.Context) ([]string, error) {
 	return namespaces, nil
 }
 
-func (s *namespaceStore) Delete(ctx context.Context, namespace string) error {
+func (s *namespaceStore) Delete(ctx context.Context, namespace string, opts ...namespaces.DeleteOpts) error {
+	i := &namespaces.DeleteInfo{
+		Name: namespace,
+	}
+	for _, o := range opts {
+		if err := o(ctx, i); err != nil {
+			return err
+		}
+	}
 	bkt := getBucket(s.tx, bucketKeyVersion)
 	if empty, err := s.namespaceEmpty(ctx, namespace); err != nil {
 		return err

namespaces.go

@@ -100,10 +100,18 @@ func (r *remoteNamespaces) List(ctx context.Context) ([]string, error) {
 	return namespaces, nil
 }
 
-func (r *remoteNamespaces) Delete(ctx context.Context, namespace string) error {
-	var req api.DeleteNamespaceRequest
-
-	req.Name = namespace
+func (r *remoteNamespaces) Delete(ctx context.Context, namespace string, opts ...namespaces.DeleteOpts) error {
+	i := namespaces.DeleteInfo{
+		Name: namespace,
+	}
+	for _, o := range opts {
+		if err := o(ctx, &i); err != nil {
+			return err
+		}
+	}
+	req := api.DeleteNamespaceRequest{
+		Name: namespace,
+	}
 	_, err := r.client.Delete(ctx, &req)
 	if err != nil {
 		return errdefs.FromGRPC(err)

namespaces/store.go

@@ -33,5 +33,14 @@ type Store interface {
 	List(ctx context.Context) ([]string, error)
 
 	// Delete removes the namespace. The namespace must be empty to be deleted.
-	Delete(ctx context.Context, namespace string) error
+	Delete(ctx context.Context, namespace string, opts ...DeleteOpts) error
 }
+
+// DeleteInfo specifies information for the deletion of a namespace
+type DeleteInfo struct {
+	// Name of the namespace
+	Name string
+}
+
+// DeleteOpts allows the caller to set options for namespace deletion
+type DeleteOpts func(context.Context, *DeleteInfo) error

namespaces_opts_linux.go

@@ -0,0 +1,36 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package containerd
+
+import (
+	"context"
+
+	"github.com/containerd/cgroups"
+	"github.com/containerd/containerd/namespaces"
+)
+
+// WithNamespaceCgroupDeletion removes the cgroup directory that was created for the namespace
+func WithNamespaceCgroupDeletion(ctx context.Context, i *namespaces.DeleteInfo) error {
+	cg, err := cgroups.Load(cgroups.V1, cgroups.StaticPath(i.Name))
+	if err != nil {
+		if err == cgroups.ErrCgroupDeleted {
+			return nil
+		}
+		return err
+	}
+	return cg.Delete()
+}