Add option to register on TCP server

Signed-off-by: Aldo Culquicondor <acondor@google.com>

docs/config.md

@@ -15,6 +15,10 @@ version = 2
 # The 'plugins."io.containerd.grpc.v1.cri"' table contains all of the server options.
 [plugins."io.containerd.grpc.v1.cri"]
 
+  # disable_tcp_service disables serving CRI on the TCP server.
+  # Note that a TCP server is enabled for containerd if TCPAddress is set in section [grpc].
+  disable_tcp_service = true
+
   # stream_server_address is the ip address streaming server is listening on.
   stream_server_address = "127.0.0.1"
 

pkg/config/config.go

@@ -138,6 +138,8 @@ type PluginConfig struct {
 	CniConfig `toml:"cni" json:"cni"`
 	// Registry contains config related to the registry
 	Registry Registry `toml:"registry" json:"registry"`
+	// DisableTCPService disables serving CRI on the TCP server.
+	DisableTCPService bool `toml:"disable_tcp_service" json:"disableTCPService"`
 	// StreamServerAddress is the ip address streaming server is listening on.
 	StreamServerAddress string `toml:"stream_server_address" json:"streamServerAddress"`
 	// StreamServerPort is the port streaming server is listening on.
@@ -219,6 +221,7 @@ func DefaultConfig() PluginConfig {
 				},
 			},
 		},
+		DisableTCPService:   true,
 		StreamServerAddress: "127.0.0.1",
 		StreamServerPort:    "0",
 		StreamIdleTimeout:   streaming.DefaultConfig.StreamIdleTimeout.String(), // 4 hour

pkg/server/service.go

@@ -171,9 +171,15 @@ func NewCRIService(config criconfig.Config, client *containerd.Client) (CRIServi
 // Register registers all required services onto a specific grpc server.
 // This is used by containerd cri plugin.
 func (c *criService) Register(s *grpc.Server) error {
-	instrumented := newInstrumentedService(c)
-	runtime.RegisterRuntimeServiceServer(s, instrumented)
-	runtime.RegisterImageServiceServer(s, instrumented)
+	return c.register(s)
+}
+
+// RegisterTCP register all required services onto a GRPC server on TCP.
+// This is used by containerd CRI plugin.
+func (c *criService) RegisterTCP(s *grpc.Server) error {
+	if !c.config.DisableTCPService {
+		return c.register(s)
+	}
 	return nil
 }
 
@@ -267,6 +273,13 @@ func (c *criService) Close() error {
 	return nil
 }
 
+func (c *criService) register(s *grpc.Server) error {
+	instrumented := newInstrumentedService(c)
+	runtime.RegisterRuntimeServiceServer(s, instrumented)
+	runtime.RegisterImageServiceServer(s, instrumented)
+	return nil
+}
+
 // imageFSPath returns containerd image filesystem path.
 // Note that if containerd changes directory layout, we also needs to change this.
 func imageFSPath(rootDir, snapshotter string) string {