Add a dockershim package

Add a new docker integration with kubelet using the new runtime API.
This change adds the package with some skeletons, and implements some
of the basic operations.

pkg/kubelet/dockershim/docker_sandbox.go

@@ -0,0 +1,51 @@
+/*
+Copyright 2016 The Kubernetes 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 dockershim
+
+import (
+	"fmt"
+
+	runtimeApi "k8s.io/kubernetes/pkg/kubelet/api/v1alpha1/runtime"
+)
+
+// CreatePodSandbox creates a pod-level sandbox.
+// The definition of PodSandbox is at https://github.com/kubernetes/kubernetes/pull/25899
+func (ds *dockerService) CreatePodSandbox(config *runtimeApi.PodSandboxConfig) (string, error) {
+	return "", fmt.Errorf("Not implemented")
+}
+
+// StopPodSandbox stops the sandbox. If there are any running containers in the
+// sandbox, they should be force terminated.
+func (ds *dockerService) StopPodSandbox(podSandboxID string) error {
+	return fmt.Errorf("Not implemented")
+}
+
+// DeletePodSandbox deletes the sandbox. If there are running containers in the
+// sandbox, they should be forcibly deleted.
+func (ds *dockerService) DeletePodSandbox(podSandboxID string) error {
+	return fmt.Errorf("Not implemented")
+}
+
+// PodSandboxStatus returns the Status of the PodSandbox.
+func (ds *dockerService) PodSandboxStatus(podSandboxID string) (*runtimeApi.PodSandboxStatus, error) {
+	return nil, fmt.Errorf("Not implemented")
+}
+
+// ListPodSandbox returns a list of Sandbox.
+func (ds *dockerService) ListPodSandbox(filter *runtimeApi.PodSandboxFilter) ([]*runtimeApi.PodSandbox, error) {
+	return nil, fmt.Errorf("Not implemented")
+}