devmapper: register plugin

Signed-off-by: Maksym Pavlenko <makpav@amazon.com>

cmd/containerd/builtins_linux.go

@@ -22,6 +22,7 @@ import (
 	_ "github.com/containerd/containerd/runtime/v1/linux"
 	_ "github.com/containerd/containerd/runtime/v2"
 	_ "github.com/containerd/containerd/runtime/v2/runc/options"
+	_ "github.com/containerd/containerd/snapshots/devmapper"
 	_ "github.com/containerd/containerd/snapshots/native"
 	_ "github.com/containerd/containerd/snapshots/overlay"
 	_ "github.com/containerd/zfs"

snapshots/devmapper/snapshotter.go

@@ -27,14 +27,44 @@ import (
 
 	"github.com/containerd/containerd/log"
 	"github.com/containerd/containerd/mount"
+	"github.com/containerd/containerd/plugin"
 	"github.com/containerd/containerd/snapshots"
 	"github.com/containerd/containerd/snapshots/devmapper/dmsetup"
 	"github.com/containerd/containerd/snapshots/storage"
 	"github.com/hashicorp/go-multierror"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 )
 
+func init() {
+	plugin.Register(&plugin.Registration{
+		Type: plugin.SnapshotPlugin,
+		ID:   "devmapper",
+		Config: &Config{
+			PoolName:      "containerd-pool",
+			BaseImageSize: "128Mb",
+		},
+		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
+			ic.Meta.Platforms = append(ic.Meta.Platforms, ocispec.Platform{
+				OS:           "linux",
+				Architecture: "amd64",
+			})
+
+			config, ok := ic.Config.(*Config)
+			if !ok {
+				return nil, errors.New("invalid devmapper configuration")
+			}
+
+			if config.RootPath == "" {
+				config.RootPath = ic.Root
+			}
+
+			return NewSnapshotter(ic.Context, config)
+		},
+	})
+}
+
 const (
 	metadataFileName = "metadata.db"
 	fsTypeExt4       = "ext4"