Fix backward compatibility with old task shims

Signed-off-by: Maksym Pavlenko <pavlenko.maksym@gmail.com>

integration/client/container_linux_test.go

@@ -433,7 +433,7 @@ func getLogDirPath(runtimeVersion, id string) string {
 	case "v1":
 		return filepath.Join(defaultRoot, plugin.RuntimeLinuxV1, testNamespace, id)
 	case "v2":
-		return filepath.Join(defaultState, "io.containerd.runtime.v2.shim", testNamespace, id)
+		return filepath.Join(defaultState, "io.containerd.runtime.v2.task", testNamespace, id)
 	default:
 		panic(fmt.Errorf("Unsupported runtime version %s", runtimeVersion))
 	}

plugin/plugin.go

@@ -57,8 +57,8 @@ const (
 	RuntimePlugin Type = "io.containerd.runtime.v1"
 	// RuntimePluginV2 implements a runtime v2
 	RuntimePluginV2 Type = "io.containerd.runtime.v2"
-	// RuntimePluginV2Service is a shim provided service implemented on top of runtime v2 plugins.
-	RuntimePluginV2Service Type = "io.containerd.runtime.v2.service"
+	// RuntimeShimPlugin implements the shim manager for runtime v2.
+	RuntimeShimPlugin Type = "io.containerd.runtime-shim.v2"
 	// ServicePlugin implements a internal service
 	ServicePlugin Type = "io.containerd.service.v1"
 	// GRPCPlugin implements a grpc service

runtime/v2/manager.go

@@ -48,7 +48,7 @@ type Config struct {
 
 func init() {
 	plugin.Register(&plugin.Registration{
-		Type: plugin.RuntimePluginV2,
+		Type: plugin.RuntimeShimPlugin,
 		ID:   "shim",
 		Requires: []plugin.Type{
 			plugin.EventPlugin,
@@ -65,12 +65,7 @@ func init() {
 			}
 
 			ic.Meta.Platforms = supportedPlatforms
-			if err := os.MkdirAll(ic.Root, 0711); err != nil {
-				return nil, err
-			}
-			if err := os.MkdirAll(ic.State, 0711); err != nil {
-				return nil, err
-			}
+
 			m, err := ic.Get(plugin.MetadataPlugin)
 			if err != nil {
 				return nil, err
@@ -95,18 +90,47 @@ func init() {
 	})
 
 	plugin.Register(&plugin.Registration{
-		Type: plugin.RuntimePluginV2Service,
+		Type: plugin.RuntimePluginV2,
 		ID:   "task",
 		Requires: []plugin.Type{
-			plugin.RuntimePluginV2,
+			plugin.RuntimeShimPlugin,
 		},
 		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
-			shimInstance, err := ic.GetByID(plugin.RuntimePluginV2, "shim")
+			m, err := ic.Get(plugin.MetadataPlugin)
+			if err != nil {
+				return nil, err
+			}
+			ep, err := ic.GetByID(plugin.EventPlugin, "exchange")
+			if err != nil {
+				return nil, err
+			}
+			cs := metadata.NewContainerStore(m.(*metadata.DB))
+			events := ep.(*exchange.Exchange)
+
+			shimManager, err := NewShimManager(ic.Context, &ManagerConfig{
+				Root:         ic.Root,
+				State:        ic.State,
+				Address:      ic.Address,
+				TTRPCAddress: ic.TTRPCAddress,
+				Events:       events,
+				Store:        cs,
+				SchedCore:    false,
+			})
 			if err != nil {
 				return nil, err
 			}
 
-			shimManager := shimInstance.(*ShimManager)
+			// Internally task manager relies on shim manager to launch task shims.
+			// It's also possible to use shim manager independently and launch other types of shims.
+			//
+			// Ideally task manager should depend on shim instance we registered above, however it'll use
+			// different home directory (`io.containerd.runtime.v2.task` vs `io.containerd.runtime.v2.shim`),
+			// which will break backward compatibility when upgrading containerd to the new version.
+			//
+			// For now, we create another instance of shim manager with the "old" home directory, so shim tasks
+			// are properly restored, but will work independently.
+			//
+			// See more context https://github.com/containerd/containerd/pull/5918#discussion_r705434412
 			return NewTaskManager(shimManager), nil
 		},
 	})
@@ -420,7 +444,7 @@ func NewTaskManager(shims *ShimManager) *TaskManager {
 
 // ID of the task manager
 func (m *TaskManager) ID() string {
-	return fmt.Sprintf("%s.%s", plugin.RuntimePluginV2Service, "task")
+	return fmt.Sprintf("%s.%s", plugin.RuntimeShimPlugin, "task")
 }
 
 // Create launches new shim instance and creates new task

services/tasks/local.go

@@ -81,7 +81,7 @@ func initFunc(ic *plugin.InitContext) (interface{}, error) {
 		return nil, err
 	}
 
-	v2r, err := ic.GetByID(plugin.RuntimePluginV2Service, "task")
+	v2r, err := ic.GetByID(plugin.RuntimePluginV2, "task")
 	if err != nil {
 		return nil, err
 	}

services/tasks/local_freebsd.go

@@ -24,7 +24,7 @@ import (
 var tasksServiceRequires = []plugin.Type{
 	plugin.EventPlugin,
 	plugin.RuntimePluginV2,
-	plugin.RuntimePluginV2Service,
+	plugin.RuntimeShimPlugin,
 	plugin.MetadataPlugin,
 	plugin.TaskMonitorPlugin,
 }

services/tasks/local_unix.go

@@ -30,7 +30,7 @@ var tasksServiceRequires = []plugin.Type{
 	plugin.EventPlugin,
 	plugin.RuntimePlugin,
 	plugin.RuntimePluginV2,
-	plugin.RuntimePluginV2Service,
+	plugin.RuntimeShimPlugin,
 	plugin.MetadataPlugin,
 	plugin.TaskMonitorPlugin,
 }

services/tasks/local_windows.go

@@ -24,7 +24,7 @@ import (
 var tasksServiceRequires = []plugin.Type{
 	plugin.EventPlugin,
 	plugin.RuntimePluginV2,
-	plugin.RuntimePluginV2Service,
+	plugin.RuntimeShimPlugin,
 	plugin.MetadataPlugin,
 	plugin.TaskMonitorPlugin,
 }