bump up the default runtime to "io.containerd.runc.v2"

The former default runtime "io.containerd.runc.v1" won't support new features
like support for cgroup v2: containerd/containerd#3726

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

docs/config.md

@@ -104,8 +104,10 @@ version = 2
     # of runtime configurations, to the matching configurations.
     # In this example, 'runc' is the RuntimeHandler string to match.
     [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc]
-      # runtime_type is the runtime type to use in containerd e.g. io.containerd.runtime.v1.linux
-      runtime_type = "io.containerd.runc.v1"
+      # runtime_type is the runtime type to use in containerd.
+      # The default value is "io.containerd.runc.v2" since containerd 1.4.
+      # The default value was "io.containerd.runc.v1" in containerd 1.3, "io.containerd.runtime.v1.linux" in prior releases.
+      runtime_type = "io.containerd.runc.v2"
 
       # pod_annotations is a list of pod annotations passed to both pod
       # sandbox as well as container OCI annotations. Pod_annotations also
@@ -129,8 +131,8 @@ version = 2
       privileged_without_host_devices = false
 
       # 'plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options' is options specific to
-      # "io.containerd.runc.v1". Its corresponding options type is:
-      #   https://github.com/containerd/containerd/blob/v1.2.0-rc.1/runtime/v2/runc/options/oci.pb.go#L39.
+      # "io.containerd.runc.v1" and "io.containerd.runc.v2". Its corresponding options type is:
+      #   https://github.com/containerd/containerd/blob/v1.3.2/runtime/v2/runc/options/oci.pb.go#L26 .
       [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options]
         # NoPivotRoot disables pivot root when creating a container.
         NoPivotRoot = false
@@ -159,6 +161,12 @@ version = 2
         # SystemdCgroup enables systemd cgroups.
         SystemdCgroup = false
 
+        # CriuImagePath is the criu image path
+        CriuImagePath = ""
+
+        # CriuWorkPath is the criu work path.
+        CriuWorkPath = ""
+
   # 'plugins."io.containerd.grpc.v1.cri".cni' contains config related to cni
   [plugins."io.containerd.grpc.v1.cri".cni]
     # bin_dir is the directory in which the binaries for the plugin is kept.

pkg/config/config_unix.go

@@ -38,7 +38,7 @@ func DefaultConfig() PluginConfig {
 			NoPivot:            false,
 			Runtimes: map[string]Runtime{
 				"runc": {
-					Type: "io.containerd.runc.v1",
+					Type: "io.containerd.runc.v2",
 				},
 			},
 		},

pkg/server/sandbox_run_unix.go

@@ -298,7 +298,7 @@ func (c *criService) cleanupSandboxFiles(id string, config *runtime.PodSandboxCo
 func (c *criService) taskOpts(runtimeType string) []containerd.NewTaskOpts {
 	// TODO(random-liu): Remove this after shim v1 is deprecated.
 	var taskOpts []containerd.NewTaskOpts
-	if c.config.NoPivot && runtimeType == plugin.RuntimeRuncV1 {
+	if c.config.NoPivot && (runtimeType == plugin.RuntimeRuncV1 || runtimeType == plugin.RuntimeRuncV2) {
 		taskOpts = append(taskOpts, containerd.WithNoPivotRoot)
 	}
 	return taskOpts