Remove /run mount for backward compatibility with docker.

Signed-off-by: Lantao Liu <lantaol@google.com>

pkg/server/container_create.go

@@ -233,7 +233,7 @@ func (c *criContainerdService) CreateContainer(ctx context.Context, r *runtime.C
 func (c *criContainerdService) generateContainerSpec(id string, sandboxPid uint32, config *runtime.ContainerConfig,
 	sandboxConfig *runtime.PodSandboxConfig, imageConfig *imagespec.ImageConfig, extraMounts []*runtime.Mount) (*runtimespec.Spec, error) {
 	// Creates a spec Generator with the default spec.
-	spec, err := containerd.GenerateSpec(context.Background(), nil, nil)
+	spec, err := defaultRuntimeSpec()
 	if err != nil {
 		return nil, err
 	}
@@ -609,3 +609,23 @@ func setOCINamespaces(g *generate.Generator, namespaces *runtime.NamespaceOption
 		g.RemoveLinuxNamespace(string(runtimespec.PIDNamespace)) // nolint: errcheck
 	}
 }
+
+// defaultRuntimeSpec returns a default runtime spec used in cri-containerd.
+func defaultRuntimeSpec() (*runtimespec.Spec, error) {
+	spec, err := containerd.GenerateSpec(context.Background(), nil, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	// Remove `/run` mount
+	// TODO(random-liu): Mount tmpfs for /run and handle copy-up.
+	var mounts []runtimespec.Mount
+	for _, mount := range spec.Mounts {
+		if mount.Destination == "/run" {
+			continue
+		}
+		mounts = append(mounts, mount)
+	}
+	spec.Mounts = mounts
+	return spec, nil
+}

pkg/server/container_create_test.go

@@ -555,3 +555,11 @@ func TestPidNamespace(t *testing.T) {
 		Type: runtimespec.PIDNamespace,
 	})
 }
+
+func TestDefaultRuntimeSpec(t *testing.T) {
+	spec, err := defaultRuntimeSpec()
+	assert.NoError(t, err)
+	for _, mount := range spec.Mounts {
+		assert.NotEqual(t, "/run", mount.Destination)
+	}
+}

pkg/server/sandbox_run.go

@@ -212,7 +212,7 @@ func (c *criContainerdService) generateSandboxContainerSpec(id string, config *r
 	imageConfig *imagespec.ImageConfig, nsPath string) (*runtimespec.Spec, error) {
 	// Creates a spec Generator with the default spec.
 	// TODO(random-liu): [P1] Compare the default settings with docker and containerd default.
-	spec, err := containerd.GenerateSpec(context.Background(), nil, nil)
+	spec, err := defaultRuntimeSpec()
 	if err != nil {
 		return nil, err
 	}