Generalize the plugin package

Remove containerd specific parts of the plugin package to prepare its
move out of the main repository. Separate the plugin registration
singleton into a separate package.

Separating out the plugin package and registration makes it easier to
implement external plugins without creating a dependency loop.

Signed-off-by: Derek McGowan <derek@mcg.dev>

cmd/containerd/command/config.go

@@ -24,7 +24,7 @@ import (
 	"github.com/containerd/containerd/defaults"
 	"github.com/containerd/containerd/images"
 	"github.com/containerd/containerd/pkg/timeout"
-	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/services/server"
 	srvconfig "github.com/containerd/containerd/services/server/config"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
@@ -46,7 +46,7 @@ func outputConfig(ctx gocontext.Context, config *srvconfig.Config) error {
 				continue
 			}
 
-			pc, err := config.Decode(ctx, p)
+			pc, err := config.Decode(ctx, p.URI(), p.Config)
 			if err != nil {
 				return err
 			}
@@ -113,7 +113,7 @@ var configCommand = cli.Command{
 				}
 
 				if config.Version < srvconfig.CurrentConfigVersion {
-					plugins := plugin.Graph(srvconfig.V2DisabledFilter(config.DisabledPlugins))
+					plugins := registry.Graph(srvconfig.V2DisabledFilter(config.DisabledPlugins))
 					for _, p := range plugins {
 						if p.ConfigMigration != nil {
 							if err := p.ConfigMigration(ctx, config.Version, config.Plugins); err != nil {

diff/lcow/lcow.go

@@ -36,6 +36,7 @@ import (
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/mount"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/log"
 	digest "github.com/opencontainers/go-digest"
@@ -48,7 +49,7 @@ const (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.DiffPlugin,
 		ID:   "windows-lcow",
 		Requires: []plugin.Type{

diff/walking/plugin/plugin.go

@@ -23,11 +23,12 @@ import (
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.DiffPlugin,
 		ID:   "walking",
 		Requires: []plugin.Type{

diff/windows/windows.go

@@ -39,6 +39,7 @@ import (
 	"github.com/containerd/containerd/pkg/epoch"
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/log"
 	"github.com/opencontainers/go-digest"
@@ -46,7 +47,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.DiffPlugin,
 		ID:   "windows",
 		Requires: []plugin.Type{

events/plugin/plugin.go

@@ -19,11 +19,12 @@ package plugin
 import (
 	"github.com/containerd/containerd/events/exchange"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.EventPlugin,
 		ID:   "exchange",
 		InitFn: func(ic *plugin.InitContext) (interface{}, error) {

gc/scheduler/scheduler.go

@@ -25,6 +25,7 @@ import (
 
 	"github.com/containerd/containerd/gc"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/log"
 )
@@ -97,7 +98,7 @@ func (d duration) MarshalText() (text []byte, err error) {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GCPlugin,
 		ID:   "scheduler",
 		Requires: []plugin.Type{

integration/build_local_containerd_helper_test.go

@@ -26,6 +26,7 @@ import (
 	"github.com/containerd/containerd/pkg/cri/constants"
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugins"
 	ctrdsrv "github.com/containerd/containerd/services/server"
 	srvconfig "github.com/containerd/containerd/services/server/config"
 	"github.com/containerd/log/logtest"
@@ -54,7 +55,7 @@ import (
 
 var (
 	loadPluginOnce   sync.Once
-	loadedPlugins    []*plugin.Registration
+	loadedPlugins    []plugin.Registration
 	loadedPluginsErr error
 )
 
@@ -88,15 +89,16 @@ func buildLocalContainerdClient(t *testing.T, tmpDir string) *containerd.Client
 	for _, p := range loadedPlugins {
 		initContext := plugin.NewContext(
 			ctx,
-			p,
 			initialized,
-			config.Root,
-			config.State,
+			map[string]string{
+				plugins.PropertyRootDir:  filepath.Join(config.Root, p.URI()),
+				plugins.PropertyStateDir: filepath.Join(config.State, p.URI()),
+			},
 		)
 
 		// load the plugin specific configuration if it is provided
 		if p.Config != nil {
-			pc, err := config.Decode(ctx, p)
+			pc, err := config.Decode(ctx, p.URI(), p.Config)
 			assert.NoError(t, err)
 
 			initContext.Config = pc

integration/failpoint/cmd/containerd-shim-runc-fp-v1/plugin_linux.go

@@ -28,6 +28,7 @@ import (
 	"github.com/containerd/containerd/pkg/failpoint"
 	"github.com/containerd/containerd/pkg/shutdown"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/runtime/v2/runc/task"
 	"github.com/containerd/containerd/runtime/v2/shim"
@@ -39,7 +40,7 @@ const (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.TTRPCPlugin,
 		ID:   "task",
 		Requires: []plugin.Type{

leases/plugin/local.go

@@ -23,11 +23,12 @@ import (
 	"github.com/containerd/containerd/leases"
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.LeasePlugin,
 		ID:   "manager",
 		Requires: []plugin.Type{

metadata/plugin/plugin.go

@@ -28,6 +28,7 @@ import (
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/pkg/timeout"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/snapshots"
 	"github.com/containerd/log"
@@ -82,7 +83,7 @@ func (bc *BoltConfig) Validate() error {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.MetadataPlugin,
 		ID:   "bolt",
 		Requires: []plugin.Type{
@@ -94,7 +95,8 @@ func init() {
 			ContentSharingPolicy: SharingPolicyShared,
 		},
 		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
-			if err := os.MkdirAll(ic.Root, 0711); err != nil {
+			root := ic.Properties[plugins.PropertyRootDir]
+			if err := os.MkdirAll(root, 0711); err != nil {
 				return nil, err
 			}
 			cs, err := ic.Get(plugins.ContentPlugin)
@@ -141,7 +143,7 @@ func init() {
 				}
 			}
 
-			path := filepath.Join(ic.Root, "meta.db")
+			path := filepath.Join(root, "meta.db")
 			ic.Meta.Exports["path"] = path
 
 			options := *bolt.DefaultOptions

metrics/cgroups/cgroups.go

@@ -25,6 +25,7 @@ import (
 	v2 "github.com/containerd/containerd/metrics/cgroups/v2"
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/runtime"
 	metrics "github.com/docker/go-metrics"
@@ -36,7 +37,7 @@ type Config struct {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:   plugins.TaskMonitorPlugin,
 		ID:     "cgroups",
 		InitFn: New,

pkg/cri/cri.go

@@ -27,6 +27,7 @@ import (
 	nriservice "github.com/containerd/containerd/pkg/nri"
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/log"
 	imagespec "github.com/opencontainers/image-spec/specs-go/v1"
@@ -39,7 +40,7 @@ import (
 // Register CRI service plugin
 func init() {
 	config := criconfig.DefaultConfig()
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:   plugins.GRPCPlugin,
 		ID:     "cri",
 		Config: &config,
@@ -63,10 +64,10 @@ func initCRIService(ic *plugin.InitContext) (interface{}, error) {
 
 	c := criconfig.Config{
 		PluginConfig:       *pluginConfig,
-		ContainerdRootDir:  filepath.Dir(ic.Root),
-		ContainerdEndpoint: ic.Address,
-		RootDir:            ic.Root,
-		StateDir:           ic.State,
+		ContainerdRootDir:  filepath.Dir(ic.Properties[plugins.PropertyRootDir]),
+		ContainerdEndpoint: ic.Properties[plugins.PropertyGRPCAddress],
+		RootDir:            ic.Properties[plugins.PropertyRootDir],
+		StateDir:           ic.Properties[plugins.PropertyStateDir],
 	}
 	log.G(ctx).Infof("Start cri plugin with config %+v", c)
 

pkg/nri/plugin/plugin.go

@@ -19,11 +19,12 @@ package plugin
 import (
 	"github.com/containerd/containerd/pkg/nri"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:   plugins.NRIApiPlugin,
 		ID:     "nri",
 		Config: nri.DefaultConfig(),

plugin/context.go

@@ -19,20 +19,15 @@ package plugin
 import (
 	"context"
 	"fmt"
-	"path/filepath"
 
-	"github.com/containerd/containerd/errdefs"
-	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+	imagespec "github.com/opencontainers/image-spec/specs-go/v1"
 )
 
 // InitContext is used for plugin initialization
 type InitContext struct {
 	Context           context.Context
-	Root              string
-	State             string
+	Properties        map[string]string
 	Config            interface{}
-	Address           string
-	TTRPCAddress      string
 	RegisterReadiness func() func()
 
 	// Meta is metadata plugins can fill in at init
@@ -42,11 +37,13 @@ type InitContext struct {
 }
 
 // NewContext returns a new plugin InitContext
-func NewContext(ctx context.Context, r *Registration, plugins *Set, root, state string) *InitContext {
+func NewContext(ctx context.Context, plugins *Set, properties map[string]string) *InitContext {
+	if properties == nil {
+		properties = map[string]string{}
+	}
 	return &InitContext{
 		Context:    ctx,
-		Root:    filepath.Join(root, r.URI()),
-		State:   filepath.Join(state, r.URI()),
+		Properties: properties,
 		Meta: &Meta{
 			Exports: map[string]string{},
 		},
@@ -62,16 +59,16 @@ func (i *InitContext) Get(t Type) (interface{}, error) {
 // Meta contains information gathered from the registration and initialization
 // process.
 type Meta struct {
-	Platforms    []ocispec.Platform // platforms supported by plugin
+	Platforms    []imagespec.Platform // platforms supported by plugin
 	Exports      map[string]string    // values exported by plugin
 	Capabilities []string             // feature switches for plugin
 }
 
 // Plugin represents an initialized plugin, used with an init context.
 type Plugin struct {
-	Registration *Registration // registration, as initialized
+	Registration Registration // registration, as initialized
 	Config       interface{}  // config, as initialized
-	Meta         *Meta
+	Meta         Meta
 
 	instance interface{}
 	err      error // will be set if there was an error initializing the plugin
@@ -115,7 +112,7 @@ func (ps *Set) Add(p *Plugin) error {
 	} else if _, idok := byID[p.Registration.ID]; !idok {
 		byID[p.Registration.ID] = p
 	} else {
-		return fmt.Errorf("plugin %v already initialized: %w", p.Registration.URI(), errdefs.ErrAlreadyExists)
+		return fmt.Errorf("plugin add failed for %s: %w", p.Registration.URI(), ErrPluginInitialized)
 	}
 
 	ps.ordered = append(ps.ordered, p)
@@ -127,7 +124,7 @@ func (ps *Set) Get(t Type) (interface{}, error) {
 	for _, v := range ps.byTypeAndID[t] {
 		return v.Instance()
 	}
-	return nil, fmt.Errorf("no plugins registered for %s: %w", t, errdefs.ErrNotFound)
+	return nil, fmt.Errorf("no plugins registered for %s: %w", t, ErrPluginNotFound)
 }
 
 // GetAll returns all initialized plugins
@@ -153,7 +150,7 @@ func (i *InitContext) GetByID(t Type, id string) (interface{}, error) {
 	}
 	p, ok := ps[id]
 	if !ok {
-		return nil, fmt.Errorf("no %s plugins with id %s: %w", t, id, errdefs.ErrNotFound)
+		return nil, fmt.Errorf("no %s plugins with id %s: %w", t, id, ErrPluginNotFound)
 	}
 	return p.Instance()
 }
@@ -162,7 +159,7 @@ func (i *InitContext) GetByID(t Type, id string) (interface{}, error) {
 func (i *InitContext) GetByType(t Type) (map[string]*Plugin, error) {
 	p, ok := i.plugins.byTypeAndID[t]
 	if !ok {
-		return nil, fmt.Errorf("no plugins registered for %s: %w", t, errdefs.ErrNotFound)
+		return nil, fmt.Errorf("no plugins registered for %s: %w", t, ErrPluginNotFound)
 	}
 
 	return p, nil

plugin/plugin.go

@@ -20,7 +20,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"sync"
 )
 
 var (
@@ -34,6 +33,10 @@ var (
 	// this allows the plugin loader differentiate between a plugin which is configured
 	// not to load and one that fails to load.
 	ErrSkipPlugin = errors.New("skip plugin")
+	// ErrPluginInitialized is used when a plugin is already initialized
+	ErrPluginInitialized = errors.New("plugin: already initialized")
+	// ErrPluginNotFound is used when a plugin is looked up but not found
+	ErrPluginNotFound = errors.New("plugin: not found")
 
 	// ErrInvalidRequires will be thrown if the requirements for a plugin are
 	// defined in an invalid manner.
@@ -65,8 +68,6 @@ type Registration struct {
 	// context are passed in. The init function may modify the registration to
 	// add exports, capabilities and platform support declarations.
 	InitFn func(*InitContext) (interface{}, error)
-	// Disable the plugin from loading
-	Disable bool
 
 	// ConfigMigration allows a plugin to migrate configurations from an older
 	// version to handle plugin renames or moving of features from one plugin
@@ -79,12 +80,12 @@ type Registration struct {
 }
 
 // Init the registered plugin
-func (r *Registration) Init(ic *InitContext) *Plugin {
+func (r Registration) Init(ic *InitContext) *Plugin {
 	p, err := r.InitFn(ic)
 	return &Plugin{
 		Registration: r,
 		Config:       ic.Config,
-		Meta:         ic.Meta,
+		Meta:         *ic.Meta,
 		instance:     p,
 		err:          err,
 	}
@@ -95,11 +96,6 @@ func (r *Registration) URI() string {
 	return r.Type.String() + "." + r.ID
 }
 
-var register = struct {
-	sync.RWMutex
-	r []*Registration
-}{}
-
 // Load loads all plugins at the provided path into containerd.
 //
 // Load is currently only implemented on non-static, non-gccgo builds for amd64
@@ -118,18 +114,64 @@ func Load(path string) (err error) {
 	return loadPlugins(path)
 }
 
-// Register allows plugins to register
-func Register(r *Registration) {
-	register.Lock()
-	defer register.Unlock()
+// DisableFilter filters out disabled plugins
+type DisableFilter func(r *Registration) bool
 
+// Registry is list of registrations which can be registered to and
+// produce a filtered and ordered output.
+// The Registry itself is immutable and the list will be copied
+// and appeneded to a new registry when new items are registered.
+type Registry []*Registration
+
+// Graph computes the ordered list of registrations based on their dependencies,
+// filtering out any plugins which match the provided filter.
+func (registry Registry) Graph(filter DisableFilter) []Registration {
+	disabled := map[*Registration]bool{}
+	for _, r := range registry {
+		if filter(r) {
+			disabled[r] = true
+		}
+	}
+
+	ordered := make([]Registration, 0, len(registry)-len(disabled))
+	added := map[*Registration]bool{}
+	for _, r := range registry {
+		if disabled[r] {
+			continue
+		}
+		children(r, registry, added, disabled, &ordered)
+		if !added[r] {
+			ordered = append(ordered, *r)
+			added[r] = true
+		}
+	}
+	return ordered
+}
+
+func children(reg *Registration, registry []*Registration, added, disabled map[*Registration]bool, ordered *[]Registration) {
+	for _, t := range reg.Requires {
+		for _, r := range registry {
+			if !disabled[r] && r.URI() != reg.URI() && (t == "*" || r.Type == t) {
+				children(r, registry, added, disabled, ordered)
+				if !added[r] {
+					*ordered = append(*ordered, *r)
+					added[r] = true
+				}
+			}
+		}
+	}
+}
+
+// Register adds the registration to a Registry and returns the
+// updated Registry, panicking if registration could not succeed.
+func (registry Registry) Register(r *Registration) Registry {
 	if r.Type == "" {
 		panic(ErrNoType)
 	}
 	if r.ID == "" {
 		panic(ErrNoPluginID)
 	}
-	if err := checkUnique(r); err != nil {
+	if err := checkUnique(registry, r); err != nil {
 		panic(err)
 	}
 
@@ -139,66 +181,14 @@ func Register(r *Registration) {
 		}
 	}
 
-	register.r = append(register.r, r)
+	return append(registry, r)
 }
 
-// Reset removes all global registrations
-func Reset() {
-	register.Lock()
-	defer register.Unlock()
-	register.r = nil
-}
-
-func checkUnique(r *Registration) error {
-	for _, registered := range register.r {
+func checkUnique(registry Registry, r *Registration) error {
+	for _, registered := range registry {
 		if r.URI() == registered.URI() {
 			return fmt.Errorf("%s: %w", r.URI(), ErrIDRegistered)
 		}
 	}
 	return nil
 }
-
-// DisableFilter filters out disabled plugins
-type DisableFilter func(r *Registration) bool
-
-// Graph returns an ordered list of registered plugins for initialization.
-// Plugins in disableList specified by id will be disabled.
-func Graph(filter DisableFilter) (ordered []*Registration) {
-	register.RLock()
-	defer register.RUnlock()
-
-	for _, r := range register.r {
-		if filter(r) {
-			r.Disable = true
-		}
-	}
-
-	added := map[*Registration]bool{}
-	for _, r := range register.r {
-		if r.Disable {
-			continue
-		}
-		children(r, added, &ordered)
-		if !added[r] {
-			ordered = append(ordered, r)
-			added[r] = true
-		}
-	}
-	return ordered
-}
-
-func children(reg *Registration, added map[*Registration]bool, ordered *[]*Registration) {
-	for _, t := range reg.Requires {
-		for _, r := range register.r {
-			if !r.Disable &&
-				r.URI() != reg.URI() &&
-				(t == "*" || r.Type == t) {
-				children(r, added, ordered)
-				if !added[r] {
-					*ordered = append(*ordered, r)
-					added[r] = true
-				}
-			}
-		}
-	}
-}

plugin/plugin_test.go

@@ -22,19 +22,12 @@ import (
 	"github.com/containerd/containerd/services"
 )
 
-func registerClear() {
-	register.Lock()
-	defer register.Unlock()
-	register.r = nil
-}
-
 func mockPluginFilter(*Registration) bool {
 	return false
 }
 
 // TestContainerdPlugin tests the logic of Graph, use the containerd's plugin
 func TestContainerdPlugin(t *testing.T) {
-	registerClear()
 	// Plugin types commonly used by containerd
 	const (
 		InternalPlugin         Type = "io.containerd.internal.v1"
@@ -52,11 +45,11 @@ func TestContainerdPlugin(t *testing.T) {
 		TracingProcessorPlugin Type = "io.containerd.tracing.processor.v1"
 	)
 
-	Register(&Registration{
+	var register Registry
+	register = register.Register(&Registration{
 		Type: TaskMonitorPlugin,
 		ID:   "cgroups",
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: ServicePlugin,
 		ID:   services.TasksService,
 		Requires: []Type{
@@ -65,199 +58,165 @@ func TestContainerdPlugin(t *testing.T) {
 			MetadataPlugin,
 			TaskMonitorPlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: ServicePlugin,
 		ID:   services.IntrospectionService,
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: ServicePlugin,
 		ID:   services.NamespacesService,
 		Requires: []Type{
 			MetadataPlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: GRPCPlugin,
 		ID:   "namespaces",
 		Requires: []Type{
 			ServicePlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: GRPCPlugin,
 		ID:   "content",
 		Requires: []Type{
 			ServicePlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: GRPCPlugin,
 		ID:   "containers",
 		Requires: []Type{
 			ServicePlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: ServicePlugin,
 		ID:   services.ContainersService,
 		Requires: []Type{
 			MetadataPlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: GRPCPlugin,
 		ID:   "events",
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: GRPCPlugin,
 		ID:   "leases",
 		Requires: []Type{
 			LeasePlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: LeasePlugin,
 		ID:   "manager",
 		Requires: []Type{
 			MetadataPlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: GRPCPlugin,
 		ID:   "diff",
 		Requires: []Type{
 			ServicePlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: ServicePlugin,
 		ID:   services.DiffService,
 		Requires: []Type{
 			DiffPlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: ServicePlugin,
 		ID:   services.SnapshotsService,
 		Requires: []Type{
 			MetadataPlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: GRPCPlugin,
 		ID:   "snapshots",
 		Requires: []Type{
 			ServicePlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: GRPCPlugin,
 		ID:   "version",
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: GRPCPlugin,
 		ID:   "images",
 		Requires: []Type{
 			ServicePlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: GCPlugin,
 		ID:   "scheduler",
 		Requires: []Type{
 			MetadataPlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: RuntimePluginV2,
 		ID:   "task",
 		Requires: []Type{
 			MetadataPlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: GRPCPlugin,
 		ID:   "tasks",
 		Requires: []Type{
 			ServicePlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type:     GRPCPlugin,
 		ID:       "introspection",
 		Requires: []Type{"*"},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: ServicePlugin,
 		ID:   services.ContentService,
 		Requires: []Type{
 			MetadataPlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: GRPCPlugin,
 		ID:   "healthcheck",
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: InternalPlugin,
 		ID:   "opt",
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: GRPCPlugin,
 		ID:   "cri",
 		Requires: []Type{
 			ServicePlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: RuntimePlugin,
 		ID:   "linux",
 		Requires: []Type{
 			MetadataPlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: InternalPlugin,
 		Requires: []Type{
 			ServicePlugin,
 		},
 		ID: "restart",
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: DiffPlugin,
 		ID:   "walking",
 		Requires: []Type{
 			MetadataPlugin,
 		},
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: SnapshotPlugin,
 		ID:   "native",
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: SnapshotPlugin,
 		ID:   "overlayfs",
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: ContentPlugin,
 		ID:   "content",
-	})
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: MetadataPlugin,
 		ID:   "bolt",
 		Requires: []Type{
 			ContentPlugin,
 			SnapshotPlugin,
 		},
-	})
-
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: TracingProcessorPlugin,
 		ID:   "otlp",
-	})
-
-	Register(&Registration{
+	}).Register(&Registration{
 		Type: InternalPlugin,
 		ID:   "tracing",
 		Requires: []Type{
@@ -265,7 +224,7 @@ func TestContainerdPlugin(t *testing.T) {
 		},
 	})
 
-	ordered := Graph(mockPluginFilter)
+	ordered := register.Graph(mockPluginFilter)
 	expectedURI := []string{
 		"io.containerd.monitor.v1.cgroups",
 		"io.containerd.content.v1.content",
@@ -305,7 +264,7 @@ func TestContainerdPlugin(t *testing.T) {
 	cmpOrdered(t, ordered, expectedURI)
 }
 
-func cmpOrdered(t *testing.T, ordered []*Registration, expectedURI []string) {
+func cmpOrdered(t *testing.T, ordered []Registration, expectedURI []string) {
 	if len(ordered) != len(expectedURI) {
 		t.Fatalf("ordered compare failed, %d != %d", len(ordered), len(expectedURI))
 	}
@@ -321,6 +280,7 @@ func TestPluginGraph(t *testing.T) {
 	for _, testcase := range []struct {
 		input       []*Registration
 		expectedURI []string
+		filter      DisableFilter
 	}{
 		// test requires *
 		{
@@ -397,19 +357,25 @@ func TestPluginGraph(t *testing.T) {
 				{
 					Type: "disable",
 					ID:   "disable",
-					Disable: true,
 				},
 			},
 			expectedURI: []string{
 				"content.content",
 			},
+			filter: func(r *Registration) bool {
+				return r.Type == "disable"
+			},
 		},
 	} {
-		registerClear()
+		var register Registry
 		for _, in := range testcase.input {
-			Register(in)
+			register = register.Register(in)
 		}
-		ordered := Graph(mockPluginFilter)
+		var filter DisableFilter = mockPluginFilter
+		if testcase.filter != nil {
+			filter = testcase.filter
+		}
+		ordered := register.Graph(filter)
 		cmpOrdered(t, ordered, testcase.expectedURI)
 	}
 }

plugin/registry/register.go

@@ -0,0 +1,50 @@
+/*
+   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 registry
+
+import (
+	"sync"
+
+	"github.com/containerd/containerd/plugin"
+)
+
+var register = struct {
+	sync.RWMutex
+	r plugin.Registry
+}{}
+
+// Register allows plugins to register
+func Register(r *plugin.Registration) {
+	register.Lock()
+	defer register.Unlock()
+	register.r = register.r.Register(r)
+}
+
+// Reset removes all global registrations
+func Reset() {
+	register.Lock()
+	defer register.Unlock()
+	register.r = nil
+}
+
+// Graph returns an ordered list of registered plugins for initialization.
+// Plugins in disableList specified by id will be disabled.
+func Graph(filter plugin.DisableFilter) []plugin.Registration {
+	register.RLock()
+	defer register.RUnlock()
+	return register.r.Graph(filter)
+}

plugins/imageverifier/plugin.go

@@ -22,12 +22,13 @@ import (
 	"github.com/containerd/containerd/pkg/imageverifier/bindir"
 	"github.com/containerd/containerd/pkg/tomlext"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 )
 
 // Register default image verifier service plugin
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:   plugins.ImageVerifierPlugin,
 		ID:     "bindir",
 		Config: defaultConfig(),

plugins/sandbox/controller.go

@@ -29,6 +29,7 @@ import (
 	"github.com/containerd/containerd/mount"
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/runtime"
 	v2 "github.com/containerd/containerd/runtime/v2"
@@ -39,7 +40,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.SandboxControllerPlugin,
 		ID:   "local",
 		Requires: []plugin.Type{

plugins/sandbox/store.go

@@ -19,11 +19,12 @@ package sandbox
 import (
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.SandboxStorePlugin,
 		ID:   "local",
 		Requires: []plugin.Type{

plugins/streaming/manager.go

@@ -28,11 +28,12 @@ import (
 	"github.com/containerd/containerd/namespaces"
 	"github.com/containerd/containerd/pkg/streaming"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.StreamingPlugin,
 		ID:   "manager",
 		Requires: []plugin.Type{

plugins/transfer/plugin.go

@@ -29,6 +29,7 @@ import (
 	"github.com/containerd/containerd/pkg/unpack"
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/log"
 
@@ -40,7 +41,7 @@ import (
 
 // Register local transfer service plugin
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.TransferPlugin,
 		ID:   "local",
 		Requires: []plugin.Type{

runtime/restart/monitor/monitor.go

@@ -26,6 +26,7 @@ import (
 	"github.com/containerd/containerd"
 	"github.com/containerd/containerd/namespaces"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/runtime/restart"
 	"github.com/containerd/log"
@@ -52,7 +53,7 @@ type Config struct {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.InternalPlugin,
 		Requires: []plugin.Type{
 			plugins.EventPlugin,

runtime/v2/example/example.go

@@ -24,6 +24,7 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/pkg/shutdown"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/runtime/v2/shim"
@@ -31,7 +32,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.TTRPCPlugin,
 		ID:   "task",
 		Requires: []plugin.Type{

runtime/v2/manager.go

@@ -34,6 +34,7 @@ import (
 	"github.com/containerd/containerd/pkg/timeout"
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/protobuf"
 	"github.com/containerd/containerd/runtime"
@@ -51,7 +52,7 @@ type Config struct {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.RuntimePluginV2,
 		ID:   "task",
 		Requires: []plugin.Type{
@@ -83,10 +84,10 @@ func init() {
 			events := ep.(*exchange.Exchange)
 
 			shimManager, err := NewShimManager(ic.Context, &ManagerConfig{
-				Root:         ic.Root,
-				State:        ic.State,
-				Address:      ic.Address,
-				TTRPCAddress: ic.TTRPCAddress,
+				Root:         ic.Properties[plugins.PropertyRootDir],
+				State:        ic.Properties[plugins.PropertyStateDir],
+				Address:      ic.Properties[plugins.PropertyGRPCAddress],
+				TTRPCAddress: ic.Properties[plugins.PropertyTTRPCAddress],
 				Events:       events,
 				Store:        cs,
 				SchedCore:    config.SchedCore,
@@ -104,7 +105,7 @@ func init() {
 	// However, due to time limits and to avoid migration steps in 1.6 release,
 	// use the following workaround.
 	// This expected to be removed in 1.7.
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.RuntimePluginV2,
 		ID:   "shim",
 		InitFn: func(ic *plugin.InitContext) (interface{}, error) {

runtime/v2/runc/pause/sandbox.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/containerd/containerd/api/types"
 	"github.com/containerd/containerd/pkg/shutdown"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/runtime/v2/shim"
 	"github.com/containerd/log"
@@ -34,7 +35,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.TTRPCPlugin,
 		ID:   "pause",
 		Requires: []plugin.Type{

runtime/v2/runc/task/plugin/plugin_linux.go

@@ -19,13 +19,14 @@ package plugin
 import (
 	"github.com/containerd/containerd/pkg/shutdown"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/runtime/v2/runc/task"
 	"github.com/containerd/containerd/runtime/v2/shim"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.TTRPCPlugin,
 		ID:   "task",
 		Requires: []plugin.Type{

runtime/v2/shim/shim.go

@@ -34,6 +34,7 @@ import (
 	"github.com/containerd/containerd/namespaces"
 	"github.com/containerd/containerd/pkg/shutdown"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/protobuf"
 	"github.com/containerd/containerd/protobuf/proto"
@@ -284,7 +285,7 @@ func run(ctx context.Context, manager Manager, name string, config Config) error
 		}
 	}
 
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.InternalPlugin,
 		ID:   "shutdown",
 		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
@@ -293,7 +294,7 @@ func run(ctx context.Context, manager Manager, name string, config Config) error
 	})
 
 	// Register event plugin
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.EventPlugin,
 		ID:   "publisher",
 		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
@@ -307,24 +308,24 @@ func run(ctx context.Context, manager Manager, name string, config Config) error
 
 		ttrpcUnaryInterceptors = []ttrpc.UnaryServerInterceptor{}
 	)
-	plugins := plugin.Graph(func(*plugin.Registration) bool { return false })
-	for _, p := range plugins {
+
+	for _, p := range registry.Graph(func(*plugin.Registration) bool { return false }) {
 		id := p.URI()
 		log.G(ctx).WithField("type", p.Type).Infof("loading plugin %q...", id)
 
 		initContext := plugin.NewContext(
 			ctx,
-			p,
 			initialized,
+			map[string]string{
 				// NOTE: Root is empty since the shim does not support persistent storage,
 				// shim plugins should make use state directory for writing files to disk.
 				// The state directory will be destroyed when the shim if cleaned up or
 				// on reboot
-			"",
-			bundlePath,
+				plugins.PropertyStateDir:     filepath.Join(bundlePath, p.URI()),
+				plugins.PropertyGRPCAddress:  addressFlag,
+				plugins.PropertyTTRPCAddress: ttrpcAddress,
+			},
 		)
-		initContext.Address = addressFlag
-		initContext.TTRPCAddress = ttrpcAddress
 
 		// load the plugin specific configuration if it is provided
 		// TODO: Read configuration passed into shim, or from state directory?

services/containers/local.go

@@ -27,6 +27,7 @@ import (
 	"github.com/containerd/containerd/events"
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -38,7 +39,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.ServicePlugin,
 		ID:   services.ContainersService,
 		Requires: []plugin.Type{

services/containers/service.go

@@ -23,6 +23,7 @@ import (
 
 	api "github.com/containerd/containerd/api/services/containers/v1"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -30,7 +31,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "containers",
 		Requires: []plugin.Type{

services/content/service.go

@@ -21,13 +21,14 @@ import (
 
 	"github.com/containerd/containerd/content"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/services"
 	"github.com/containerd/containerd/services/content/contentserver"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "content",
 		Requires: []plugin.Type{

services/content/store.go

@@ -24,6 +24,7 @@ import (
 	"github.com/containerd/containerd/events"
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/services"
 	digest "github.com/opencontainers/go-digest"
@@ -36,7 +37,7 @@ type store struct {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.ServicePlugin,
 		ID:   services.ContentService,
 		Requires: []plugin.Type{

services/diff/local.go

@@ -26,6 +26,7 @@ import (
 	"github.com/containerd/containerd/mount"
 	"github.com/containerd/containerd/oci"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/services"
 	"github.com/containerd/typeurl/v2"
@@ -49,7 +50,7 @@ type differ interface {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.ServicePlugin,
 		ID:   services.DiffService,
 		Requires: []plugin.Type{

services/diff/service.go

@@ -22,13 +22,14 @@ import (
 
 	diffapi "github.com/containerd/containerd/api/services/diff/v1"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/services"
 	"google.golang.org/grpc"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "diff",
 		Requires: []plugin.Type{

services/events/service.go

@@ -26,6 +26,7 @@ import (
 	"github.com/containerd/containerd/events"
 	"github.com/containerd/containerd/events/exchange"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/protobuf"
 	ptypes "github.com/containerd/containerd/protobuf/types"
@@ -34,7 +35,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "events",
 		Requires: []plugin.Type{

services/healthcheck/service.go

@@ -18,6 +18,7 @@ package healthcheck
 
 import (
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 
 	"google.golang.org/grpc"
@@ -30,7 +31,7 @@ type service struct {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "healthcheck",
 		InitFn: func(*plugin.InitContext) (interface{}, error) {

services/images/local.go

@@ -28,6 +28,7 @@ import (
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/pkg/epoch"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -38,7 +39,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.ServicePlugin,
 		ID:   services.ImagesService,
 		Requires: []plugin.Type{

services/images/service.go

@@ -22,6 +22,7 @@ import (
 
 	imagesapi "github.com/containerd/containerd/api/services/images/v1"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -29,7 +30,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "images",
 		Requires: []plugin.Type{

services/introspection/local.go

@@ -28,6 +28,7 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/filters"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -39,7 +40,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:     plugins.ServicePlugin,
 		ID:       services.IntrospectionService,
 		Requires: []plugin.Type{},
@@ -47,7 +48,7 @@ func init() {
 			// this service fetches all plugins through the plugin set of the plugin context
 			return &Local{
 				plugins: ic.Plugins(),
-				root:    ic.Root,
+				root:    ic.Properties[plugins.PropertyRootDir],
 			}, nil
 		},
 	})

services/introspection/service.go

@@ -22,6 +22,7 @@ import (
 
 	api "github.com/containerd/containerd/api/services/introspection/v1"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -29,7 +30,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:     plugins.GRPCPlugin,
 		ID:       "introspection",
 		Requires: []plugin.Type{plugins.ServicePlugin},
@@ -52,7 +53,7 @@ func init() {
 			if !ok {
 				return nil, errors.New("could not create a local client for introspection service")
 			}
-			localClient.UpdateLocal(ic.Root)
+			localClient.UpdateLocal(ic.Properties[plugins.PropertyRootDir])
 
 			return &server{
 				local: localClient,

services/leases/service.go

@@ -23,6 +23,7 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/leases"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/protobuf"
 	ptypes "github.com/containerd/containerd/protobuf/types"
@@ -30,7 +31,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "leases",
 		Requires: []plugin.Type{

services/namespaces/local.go

@@ -27,6 +27,7 @@ import (
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/namespaces"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -37,7 +38,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.ServicePlugin,
 		ID:   services.NamespacesService,
 		Requires: []plugin.Type{

services/namespaces/service.go

@@ -22,6 +22,7 @@ import (
 
 	api "github.com/containerd/containerd/api/services/namespaces/v1"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -29,7 +30,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "namespaces",
 		Requires: []plugin.Type{

services/opt/service.go

@@ -22,6 +22,7 @@ import (
 	"path/filepath"
 
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 )
 
@@ -32,7 +33,7 @@ type Config struct {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.InternalPlugin,
 		ID:   "opt",
 		Config: &Config{

services/sandbox/controller_service.go

@@ -27,6 +27,7 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/events"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/protobuf"
 	"github.com/containerd/containerd/sandbox"
@@ -34,7 +35,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "sandbox-controllers",
 		Requires: []plugin.Type{

services/sandbox/store_service.go

@@ -25,13 +25,14 @@ import (
 	"github.com/containerd/containerd/api/types"
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/sandbox"
 	"github.com/containerd/log"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "sandboxes",
 		Requires: []plugin.Type{

services/server/config/config.go

@@ -239,11 +239,10 @@ type ProxyPlugin struct {
 }
 
 // Decode unmarshals a plugin specific configuration by plugin id
-func (c *Config) Decode(ctx context.Context, p *plugin.Registration) (interface{}, error) {
-	id := p.URI()
+func (c *Config) Decode(ctx context.Context, id string, config interface{}) (interface{}, error) {
 	data, ok := c.Plugins[id]
 	if !ok {
-		return p.Config, nil
+		return config, nil
 	}
 
 	b, err := toml.Marshal(data)
@@ -251,7 +250,7 @@ func (c *Config) Decode(ctx context.Context, p *plugin.Registration) (interface{
 		return nil, err
 	}
 
-	if err := toml.NewDecoder(bytes.NewReader(b)).DisallowUnknownFields().Decode(p.Config); err != nil {
+	if err := toml.NewDecoder(bytes.NewReader(b)).DisallowUnknownFields().Decode(config); err != nil {
 		var serr *toml.StrictMissingError
 		if errors.As(err, &serr) {
 			for _, derr := range serr.Errors {
@@ -260,7 +259,7 @@ func (c *Config) Decode(ctx context.Context, p *plugin.Registration) (interface{
 					"key":    strings.Join(derr.Key(), " "),
 				}).WithError(err).Warn("Ignoring unknown key in TOML for plugin")
 			}
-			err = toml.Unmarshal(b, p.Config)
+			err = toml.Unmarshal(b, config)
 		}
 		if err != nil {
 			return nil, err
@@ -268,7 +267,7 @@ func (c *Config) Decode(ctx context.Context, p *plugin.Registration) (interface{
 
 	}
 
-	return p.Config, nil
+	return config, nil
 }
 
 // LoadConfig loads the containerd server config from the provided path

services/server/config/config_test.go

@@ -25,7 +25,6 @@ import (
 
 	"github.com/stretchr/testify/assert"
 
-	"github.com/containerd/containerd/plugin"
 	"github.com/containerd/log/logtest"
 )
 
@@ -201,7 +200,7 @@ func TestDecodePlugin(t *testing.T) {
 	ctx := logtest.WithT(context.Background(), t)
 	data := `
 version = 2
-[plugins."io.containerd.runtime.v1.linux"]
+[plugins."io.containerd.runtime.v2.task"]
   shim_debug = true
 `
 
@@ -216,7 +215,7 @@ version = 2
 	assert.NoError(t, err)
 
 	pluginConfig := map[string]interface{}{}
-	_, err = out.Decode(ctx, &plugin.Registration{Type: "io.containerd.runtime.v1", ID: "linux", Config: &pluginConfig})
+	_, err = out.Decode(ctx, "io.containerd.runtime.v2.task", &pluginConfig)
 	assert.NoError(t, err)
 	assert.Equal(t, true, pluginConfig["shim_debug"])
 }
@@ -226,7 +225,7 @@ version = 2
 func TestDecodePluginInV1Config(t *testing.T) {
 	ctx := logtest.WithT(context.Background(), t)
 	data := `
-[plugins.linux]
+[plugins.task]
   shim_debug = true
 `
 
@@ -244,7 +243,7 @@ func TestDecodePluginInV1Config(t *testing.T) {
 	assert.Equal(t, 3, out.Version)
 
 	pluginConfig := map[string]interface{}{}
-	_, err = out.Decode(ctx, &plugin.Registration{Type: "io.containerd.runtime.v1", ID: "linux", Config: &pluginConfig})
+	_, err = out.Decode(ctx, "io.containerd.runtime.v2.task", &pluginConfig)
 	assert.NoError(t, err)
 	assert.Equal(t, true, pluginConfig["shim_debug"])
 }

services/server/server.go

@@ -46,6 +46,7 @@ import (
 	"github.com/containerd/containerd/pkg/timeout"
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	srvconfig "github.com/containerd/containerd/services/server/config"
 	ssproxy "github.com/containerd/containerd/snapshots/proxy"
@@ -245,13 +246,14 @@ func New(ctx context.Context, config *srvconfig.Config) (*Server, error) {
 
 		initContext := plugin.NewContext(
 			ctx,
-			p,
 			initialized,
-			config.Root,
-			config.State,
+			map[string]string{
+				plugins.PropertyRootDir:      filepath.Join(config.Root, id),
+				plugins.PropertyStateDir:     filepath.Join(config.State, id),
+				plugins.PropertyGRPCAddress:  config.GRPC.Address,
+				plugins.PropertyTTRPCAddress: config.TTRPC.Address,
+			},
 		)
-		initContext.Address = config.GRPC.Address
-		initContext.TTRPCAddress = config.TTRPC.Address
 		initContext.RegisterReadiness = func() func() {
 			atomic.StoreInt32(&mustSucceed, 1)
 			return s.RegisterReadiness()
@@ -259,7 +261,7 @@ func New(ctx context.Context, config *srvconfig.Config) (*Server, error) {
 
 		// load the plugin specific configuration if it is provided
 		if p.Config != nil {
-			pc, err := config.Decode(ctx, p)
+			pc, err := config.Decode(ctx, id, p.Config)
 			if err != nil {
 				return nil, err
 			}
@@ -426,7 +428,7 @@ func (s *Server) Wait() {
 
 // LoadPlugins loads all plugins into containerd and generates an ordered graph
 // of all plugins.
-func LoadPlugins(ctx context.Context, config *srvconfig.Config) ([]*plugin.Registration, error) {
+func LoadPlugins(ctx context.Context, config *srvconfig.Config) ([]plugin.Registration, error) {
 	// load all plugins into containerd
 	path := config.PluginDir
 	if path == "" {
@@ -436,12 +438,13 @@ func LoadPlugins(ctx context.Context, config *srvconfig.Config) ([]*plugin.Regis
 		return nil, err
 	}
 	// load additional plugins that don't automatically register themselves
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.ContentPlugin,
 		ID:   "content",
 		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
-			ic.Meta.Exports["root"] = ic.Root
-			return local.NewStore(ic.Root)
+			root := ic.Properties[plugins.PropertyRootDir]
+			ic.Meta.Exports["root"] = root
+			return local.NewStore(root)
 		},
 	})
 
@@ -486,7 +489,7 @@ func LoadPlugins(ctx context.Context, config *srvconfig.Config) ([]*plugin.Regis
 			p = platforms.DefaultSpec()
 		}
 
-		plugin.Register(&plugin.Registration{
+		registry.Register(&plugin.Registration{
 			Type: t,
 			ID:   name,
 			InitFn: func(ic *plugin.InitContext) (interface{}, error) {
@@ -504,7 +507,7 @@ func LoadPlugins(ctx context.Context, config *srvconfig.Config) ([]*plugin.Regis
 
 	filter := srvconfig.V2DisabledFilter
 	// return the ordered graph for plugins
-	return plugin.Graph(filter(config.DisabledPlugins)), nil
+	return registry.Graph(filter(config.DisabledPlugins)), nil
 }
 
 type proxyClients struct {

services/server/server_test.go

@@ -21,6 +21,7 @@ import (
 	"testing"
 
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	srvconfig "github.com/containerd/containerd/services/server/config"
 	"github.com/stretchr/testify/assert"
 )
@@ -57,8 +58,8 @@ func TestCreateTopLevelDirectoriesWithEmptyRootPath(t *testing.T) {
 }
 
 func TestMigration(t *testing.T) {
-	plugin.Reset()
-	defer plugin.Reset()
+	registry.Reset()
+	defer registry.Reset()
 
 	version := srvconfig.CurrentConfigVersion - 1
 
@@ -67,7 +68,7 @@ func TestMigration(t *testing.T) {
 		NotMigrated string `toml:"notmigrated"`
 	}
 
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:   "io.containerd.test",
 		ID:     "t1",
 		Config: &testConfig{},
@@ -86,7 +87,7 @@ func TestMigration(t *testing.T) {
 			return nil, nil
 		},
 	})
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: "io.containerd.new",
 		Requires: []plugin.Type{
 			"io.containerd.test", // Ensure this test runs second

services/snapshots/service.go

@@ -24,6 +24,7 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/mount"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -33,7 +34,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "snapshots",
 		Requires: []plugin.Type{

services/snapshots/snapshotters.go

@@ -19,12 +19,13 @@ package snapshots
 import (
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/services"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.ServicePlugin,
 		ID:   services.SnapshotsService,
 		Requires: []plugin.Type{

services/streaming/service.go

@@ -24,6 +24,7 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/pkg/streaming"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/protobuf"
 	ptypes "github.com/containerd/containerd/protobuf/types"
@@ -42,7 +43,7 @@ func init() {
 		panic(err)
 	}
 
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "streaming",
 		Requires: []plugin.Type{

services/tasks/local.go

@@ -19,6 +19,7 @@ package tasks
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -41,6 +42,7 @@ import (
 	"github.com/containerd/containerd/pkg/rdt"
 	"github.com/containerd/containerd/pkg/timeout"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/protobuf"
 	"github.com/containerd/containerd/protobuf/proto"
@@ -75,7 +77,7 @@ type Config struct {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:     plugins.ServicePlugin,
 		ID:       services.TasksService,
 		Requires: tasksServiceRequires,
@@ -106,7 +108,7 @@ func initFunc(ic *plugin.InitContext) (interface{}, error) {
 
 	monitor, err := ic.Get(plugins.TaskMonitorPlugin)
 	if err != nil {
-		if !errdefs.IsNotFound(err) {
+		if !errors.Is(err, plugin.ErrPluginNotFound) {
 			return nil, err
 		}
 		monitor = runtime.NewNoopMonitor()

services/tasks/service.go

@@ -22,6 +22,7 @@ import (
 
 	api "github.com/containerd/containerd/api/services/tasks/v1"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/containerd/services"
@@ -33,7 +34,7 @@ var (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "tasks",
 		Requires: []plugin.Type{

services/transfer/service.go

@@ -26,6 +26,7 @@ import (
 	"github.com/containerd/containerd/pkg/transfer"
 	tplugins "github.com/containerd/containerd/pkg/transfer/plugins"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	"github.com/containerd/log"
@@ -37,7 +38,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.GRPCPlugin,
 		ID:   "transfer",
 		Requires: []plugin.Type{

services/version/service.go

@@ -21,6 +21,7 @@ import (
 
 	api "github.com/containerd/containerd/api/services/version/v1"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	ptypes "github.com/containerd/containerd/protobuf/types"
 	ctrdversion "github.com/containerd/containerd/version"
@@ -30,7 +31,7 @@ import (
 var _ api.VersionServer = &service{}
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:   plugins.GRPCPlugin,
 		ID:     "version",
 		InitFn: initFunc,

snapshots/blockfile/plugin/plugin.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/snapshots/blockfile"
 )
@@ -45,7 +46,7 @@ type Config struct {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:   plugins.SnapshotPlugin,
 		ID:     "blockfile",
 		Config: &Config{},
@@ -58,7 +59,7 @@ func init() {
 			}
 
 			var opts []blockfile.Opt
-			root := ic.Root
+			root := ic.Properties[plugins.PropertyRootDir]
 			if len(config.RootPath) != 0 {
 				root = config.RootPath
 			}

snapshots/btrfs/plugin/plugin.go

@@ -25,6 +25,7 @@ import (
 
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/snapshots/btrfs"
 )
@@ -36,7 +37,7 @@ type Config struct {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		ID:     "btrfs",
 		Type:   plugins.SnapshotPlugin,
 		Config: &Config{},
@@ -48,7 +49,7 @@ func init() {
 				return nil, errors.New("invalid btrfs configuration")
 			}
 
-			root := ic.Root
+			root := ic.Properties[plugins.PropertyRootDir]
 			if len(config.RootPath) != 0 {
 				root = config.RootPath
 			}

snapshots/devmapper/plugin/plugin.go

@@ -24,12 +24,13 @@ import (
 
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/snapshots/devmapper"
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:   plugins.SnapshotPlugin,
 		ID:     "devmapper",
 		Config: &devmapper.Config{},
@@ -46,7 +47,7 @@ func init() {
 			}
 
 			if config.RootPath == "" {
-				config.RootPath = ic.Root
+				config.RootPath = ic.Properties[plugins.PropertyRootDir]
 			}
 
 			return devmapper.NewSnapshotter(ic.Context, config)

snapshots/lcow/lcow.go

@@ -37,6 +37,7 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/mount"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/snapshots"
 	"github.com/containerd/containerd/snapshots/storage"
@@ -46,7 +47,7 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.SnapshotPlugin,
 		ID:   "windows-lcow",
 		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
@@ -54,7 +55,7 @@ func init() {
 				OS:           "linux",
 				Architecture: runtime.GOARCH,
 			})
-			return NewSnapshotter(ic.Root)
+			return NewSnapshotter(ic.Properties[plugins.PropertyRootDir])
 		},
 	})
 }

snapshots/native/plugin/plugin.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/snapshots/native"
 )
@@ -32,7 +33,7 @@ type Config struct {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:   plugins.SnapshotPlugin,
 		ID:     "native",
 		Config: &Config{},
@@ -44,7 +45,7 @@ func init() {
 				return nil, errors.New("invalid native configuration")
 			}
 
-			root := ic.Root
+			root := ic.Properties[plugins.PropertyRootDir]
 			if len(config.RootPath) != 0 {
 				root = config.RootPath
 			}

snapshots/overlay/plugin/plugin.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/snapshots/overlay"
 	"github.com/containerd/containerd/snapshots/overlay/overlayutils"
@@ -50,7 +51,7 @@ type Config struct {
 }
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type:   plugins.SnapshotPlugin,
 		ID:     "overlayfs",
 		Config: &Config{},
@@ -62,7 +63,7 @@ func init() {
 				return nil, errors.New("invalid overlay configuration")
 			}
 
-			root := ic.Root
+			root := ic.Properties[plugins.PropertyRootDir]
 			if config.RootPath != "" {
 				root = config.RootPath
 			}

snapshots/windows/windows.go

@@ -38,6 +38,7 @@ import (
 	"github.com/containerd/containerd/mount"
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/snapshots"
 	"github.com/containerd/containerd/snapshots/storage"
@@ -47,12 +48,12 @@ import (
 )
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		Type: plugins.SnapshotPlugin,
 		ID:   "windows",
 		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
 			ic.Meta.Platforms = []ocispec.Platform{platforms.DefaultSpec()}
-			return NewSnapshotter(ic.Root)
+			return NewSnapshotter(ic.Properties[plugins.PropertyRootDir])
 		},
 	})
 }

tracing/plugin/otlp.go

@@ -25,6 +25,7 @@ import (
 
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/plugin"
+	"github.com/containerd/containerd/plugin/registry"
 	"github.com/containerd/containerd/plugins"
 	"github.com/containerd/containerd/tracing"
 	"github.com/containerd/log"
@@ -42,7 +43,7 @@ import (
 const exporterPlugin = "otlp"
 
 func init() {
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		ID:     exporterPlugin,
 		Type:   plugins.TracingProcessorPlugin,
 		Config: &OTLPConfig{},
@@ -55,7 +56,7 @@ func init() {
 			return trace.NewBatchSpanProcessor(exp), nil
 		},
 	})
-	plugin.Register(&plugin.Registration{
+	registry.Register(&plugin.Registration{
 		ID:   "tracing",
 		Type: plugins.InternalPlugin,
 		Requires: []plugin.Type{