Set /etc/hostname.

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

integration/pod_hostname_test.go

@@ -0,0 +1,120 @@
+/*
+Copyright 2018 The containerd 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 integration
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	runtime "k8s.io/kubernetes/pkg/kubelet/apis/cri/runtime/v1alpha2"
+)
+
+func TestPodHostname(t *testing.T) {
+	hostname, err := os.Hostname()
+	require.NoError(t, err)
+	for name, test := range map[string]struct {
+		opts             []PodSandboxOpts
+		expectedHostname string
+	}{
+		"regular pod with custom hostname": {
+			opts: []PodSandboxOpts{
+				WithPodHostname("test-hostname"),
+			},
+			expectedHostname: "test-hostname",
+		},
+		"host network pod without custom hostname": {
+			opts: []PodSandboxOpts{
+				WithHostNetwork,
+			},
+			expectedHostname: hostname,
+		},
+		"host network pod with custom hostname": {
+			opts: []PodSandboxOpts{
+				WithHostNetwork,
+				WithPodHostname("test-hostname"),
+			},
+			expectedHostname: "test-hostname",
+		},
+	} {
+		t.Run(name, func(t *testing.T) {
+			testPodLogDir, err := ioutil.TempDir("/tmp", "hostname")
+			require.NoError(t, err)
+			defer os.RemoveAll(testPodLogDir)
+
+			opts := append(test.opts, WithPodLogDirectory(testPodLogDir))
+			t.Log("Create a sandbox with hostname")
+			sbConfig := PodSandboxConfig("sandbox", "hostname", opts...)
+			sb, err := runtimeService.RunPodSandbox(sbConfig, *runtimeHandler)
+			require.NoError(t, err)
+			defer func() {
+				assert.NoError(t, runtimeService.StopPodSandbox(sb))
+				assert.NoError(t, runtimeService.RemovePodSandbox(sb))
+			}()
+
+			const (
+				testImage     = "busybox"
+				containerName = "test-container"
+			)
+			t.Logf("Pull test image %q", testImage)
+			img, err := imageService.PullImage(&runtime.ImageSpec{Image: testImage}, nil)
+			require.NoError(t, err)
+			defer func() {
+				assert.NoError(t, imageService.RemoveImage(&runtime.ImageSpec{Image: img}))
+			}()
+
+			t.Log("Create a container to print env")
+			cnConfig := ContainerConfig(
+				containerName,
+				testImage,
+				WithCommand("sh", "-c",
+					"echo -n /etc/hostname= && cat /etc/hostname && env"),
+				WithLogPath(containerName),
+			)
+			cn, err := runtimeService.CreateContainer(sb, cnConfig, sbConfig)
+			require.NoError(t, err)
+
+			t.Log("Start the container")
+			require.NoError(t, runtimeService.StartContainer(cn))
+
+			t.Log("Wait for container to finish running")
+			require.NoError(t, Eventually(func() (bool, error) {
+				s, err := runtimeService.ContainerStatus(cn)
+				if err != nil {
+					return false, err
+				}
+				if s.GetState() == runtime.ContainerState_CONTAINER_EXITED {
+					return true, nil
+				}
+				return false, nil
+			}, time.Second, 30*time.Second))
+
+			content, err := ioutil.ReadFile(filepath.Join(testPodLogDir, containerName))
+			assert.NoError(t, err)
+
+			t.Log("Search hostname env in container log")
+			assert.Contains(t, string(content), "HOSTNAME="+test.expectedHostname)
+
+			t.Log("Search /etc/hostname content in container log")
+			assert.Contains(t, string(content), "/etc/hostname="+test.expectedHostname)
+		})
+	}
+}