Run Linux Images (LCOW) and Windows Containers side by side (#7850)

Makes it possible to run Linux Containers On Windows with Nomad alongside Windows Containers. Fingerprint prevents only to run Nomad in Windows 10 with Linux Containers
hashicorp · May 4, 2020 · 65f09ed · 65f09ed
1 parent b3d43b8
commit 65f09ed
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Showing 3 changed files with 29 additions and 5 deletions.
diff --git a/client/allocdir/fs_windows.go b/client/allocdir/fs_windows.go
@@ -10,7 +10,7 @@ var (
 	// directory shared across tasks in a task group.
 	SharedAllocContainerPath = filepath.Join("c:\\", SharedAllocName)
 
-	// TaskLocalContainer is the path inside a container for mounted directory
+	// TaskLocalContainerPath is the path inside a container for mounted directory
 	// for local storage.
 	TaskLocalContainerPath = filepath.Join("c:\\", TaskLocal)
 

diff --git a/drivers/docker/driver.go b/drivers/docker/driver.go
@@ -274,6 +274,13 @@ func (d *Driver) StartTask(cfg *drivers.TaskConfig) (*drivers.TaskHandle, *drive
 		return nil, nil, err
 	}
 
+	if runtime.GOOS == "windows" {
+		err = d.convertAllocPathsForWindowsLCOW(cfg, driverConfig.Image)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+
 	containerCfg, err := d.createContainerConfig(cfg, &driverConfig, driverConfig.Image)
 	if err != nil {
 		d.logger.Error("failed to create container configuration", "image_name", driverConfig.Image,
@@ -616,8 +623,24 @@ func (d *Driver) loadImage(task *drivers.TaskConfig, driverConfig *TaskConfig, c
 	return dockerImage.ID, nil
 }
 
-func (d *Driver) containerBinds(task *drivers.TaskConfig, driverConfig *TaskConfig) ([]string, error) {
+func (d *Driver) convertAllocPathsForWindowsLCOW(task *drivers.TaskConfig, image string) error {
+	imageConfig, err := client.InspectImage(image)
+	if err != nil {
+		return fmt.Errorf("the image does not exist: %v", err)
+	}
+	// LCOW If we are running a Linux Container on Windows, we need to mount it correctly, as c:\ does not exist on unix
+	if imageConfig.OS == "linux" {
+		a := []rune(task.Env[taskenv.AllocDir])
+		task.Env[taskenv.AllocDir] = strings.ReplaceAll(string(a[2:]), "\\", "/")
+		l := []rune(task.Env[taskenv.TaskLocalDir])
+		task.Env[taskenv.TaskLocalDir] = strings.ReplaceAll(string(l[2:]), "\\", "/")
+		s := []rune(task.Env[taskenv.SecretsDir])
+		task.Env[taskenv.SecretsDir] = strings.ReplaceAll(string(s[2:]), "\\", "/")
+	}
+	return nil
+}
 
+func (d *Driver) containerBinds(task *drivers.TaskConfig, driverConfig *TaskConfig) ([]string, error) {
 	allocDirBind := fmt.Sprintf("%s:%s", task.TaskDir().SharedAllocDir, task.Env[taskenv.AllocDir])
 	taskLocalBind := fmt.Sprintf("%s:%s", task.TaskDir().LocalDir, task.Env[taskenv.TaskLocalDir])
 	secretDirBind := fmt.Sprintf("%s:%s", task.TaskDir().SecretsDir, task.Env[taskenv.SecretsDir])
@@ -723,7 +746,6 @@ func (d *Driver) createContainerConfig(task *drivers.TaskConfig, driverConfig *T
 		logger.Error("task.Resources is empty")
 		return c, fmt.Errorf("task.Resources is empty")
 	}
-
 	binds, err := d.containerBinds(task, driverConfig)
 	if err != nil {
 		return c, err
@@ -817,6 +839,7 @@ func (d *Driver) createContainerConfig(task *drivers.TaskConfig, driverConfig *T
 	logger.Debug("configured resources", "memory", hostConfig.Memory,
 		"cpu_shares", hostConfig.CPUShares, "cpu_quota", hostConfig.CPUQuota,
 		"cpu_period", hostConfig.CPUPeriod)
+
 	logger.Debug("binding directories", "binds", hclog.Fmt("%#v", hostConfig.Binds))
 
 	//  set privileged mode

diff --git a/drivers/docker/fingerprint.go b/drivers/docker/fingerprint.go
@@ -168,15 +168,16 @@ func (d *Driver) buildFingerprint() *drivers.Fingerprint {
 			strings.Join(runtimeNames, ","))
 		fp.Attributes["driver.docker.os_type"] = pstructs.NewStringAttribute(dockerInfo.OSType)
 
+		// If this situations arises, we are running in Windows 10 with Linux Containers enabled via VM
 		if runtime.GOOS == "windows" && dockerInfo.OSType == "linux" {
 			if d.fingerprintSuccessful() {
-				d.logger.Warn("detected Linux docker containers on Windows; only Windows containers are supported")
+				d.logger.Warn("Docker is configured with Linux containers; switch to Windows Containers")
 			}
 
 			d.setFingerprintFailure()
 			return &drivers.Fingerprint{
 				Health:            drivers.HealthStateUnhealthy,
-				HealthDescription: "Docker is configured with Linux containers; only Windows containers are supported",
+				HealthDescription: "Docker is configured with Linux containers; switch to Windows Containers",
 			}
 		}
 	}