Fix cAdivsor docker validation

container/docker/factory.go

@@ -163,6 +163,7 @@ var (
 	version_re            = regexp.MustCompile(version_regexp_string)
 )
 
+// TODO: switch to a semantic versioning library.
 func parseDockerVersion(full_version_string string) ([]int, error) {
 	matches := version_re.FindAllStringSubmatch(full_version_string, -1)
 	if len(matches) != 1 {
@@ -186,38 +187,14 @@ func Register(factory info.MachineInfoFactory, fsInfo fs.FsInfo, ignoreMetrics c
 	if err != nil {
 		return fmt.Errorf("unable to communicate with docker daemon: %v", err)
 	}
-	var dockerVersion []int
-	if version, err := client.Version(); err != nil {
-		return fmt.Errorf("unable to communicate with docker daemon: %v", err)
-	} else {
-		expected_version := []int{1, 0, 0}
-		version_string := version.Get("Version")
-		dockerVersion, err = parseDockerVersion(version_string)
-		if err != nil {
-			return fmt.Errorf("couldn't parse docker version: %v", err)
-		}
-		for index, number := range dockerVersion {
-			if number > expected_version[index] {
-				break
-			} else if number < expected_version[index] {
-				return fmt.Errorf("cAdvisor requires docker version %v or above but we have found version %v reported as \"%v\"", expected_version, dockerVersion, version_string)
-			}
-		}
-	}
 
-	dockerInfo, err := client.Info()
+	dockerInfo, err := ValidateInfo()
 	if err != nil {
-		return fmt.Errorf("failed to detect Docker info: %v", err)
-	}
-
-	// Check that the libcontainer execdriver is used.
-	if !strings.HasPrefix(dockerInfo.ExecutionDriver, "native") {
-		return fmt.Errorf("docker found, but not using native exec driver")
+		return fmt.Errorf("failed to validate Docker info: %v", err)
 	}
 
-	if dockerInfo.Driver == "" {
-		return fmt.Errorf("failed to find docker storage driver")
-	}
+	// Version already validated above, assume no error here.
+	dockerVersion, _ := parseDockerVersion(dockerInfo.ServerVersion)
 
 	storageDir := dockerInfo.DockerRootDir
 	if storageDir == "" {

container/docker/handler.go

@@ -425,3 +425,38 @@ func DockerImages() ([]docker.APIImages, error) {
 	}
 	return images, nil
 }
+
+// Checks whether the dockerInfo reflects a valid docker setup, and returns it if it does, or an
+// error otherwise.
+func ValidateInfo() (*docker.DockerInfo, error) {
+	client, err := Client()
+	if err != nil {
+		return nil, fmt.Errorf("unable to communicate with docker daemon: %v", err)
+	}
+
+	dockerInfo, err := client.Info()
+	if err != nil {
+		return nil, fmt.Errorf("failed to detect Docker info: %v", err)
+	}
+
+	version, err := parseDockerVersion(dockerInfo.ServerVersion)
+	if err != nil {
+		return nil, err
+	}
+	if version[0] < 1 {
+		return nil, fmt.Errorf("cAdvisor requires docker version %v or above but we have found version %v reported as %q", []int{1, 0, 0}, version, dockerInfo.ServerVersion)
+	}
+
+	// Check that the libcontainer execdriver is used if the version is < 1.11
+	// (execution drivers are no longer supported as of 1.11).
+	if version[0] <= 1 && version[1] <= 10 &&
+		!strings.HasPrefix(dockerInfo.ExecutionDriver, "native") {
+		return nil, fmt.Errorf("docker found, but not using native exec driver")
+	}
+
+	if dockerInfo.Driver == "" {
+		return nil, fmt.Errorf("failed to find docker storage driver")
+	}
+
+	return dockerInfo, nil
+}

manager/manager.go

@@ -233,7 +233,6 @@ func (self *manager) Start() error {
 		glog.Errorf("Registration of the raw container factory failed: %v", err)
 	}
 
-	// FIXME - delete?
 	self.DockerInfo()
 	self.DockerImages()
 

validate/validate.go

@@ -185,24 +185,19 @@ func validateCgroups() (string, string) {
 }
 
 func validateDockerInfo() (string, string) {
-	info, err := docker.DockerInfo()
+	info, err := docker.ValidateInfo()
 	if err != nil {
-		return Unknown, "Docker remote API not reachable\n\t"
+		return Unsupported, fmt.Sprintf("Docker setup is invalid: %v", err)
 	}
 
 	desc := fmt.Sprintf("Docker exec driver is %s. Storage driver is %s.\n", info.ExecutionDriver, info.Driver)
-	if strings.Contains(info.ExecutionDriver, "native") {
-		stateFile := docker.DockerStateDir()
-		if !utils.FileExists(stateFile) {
-			desc += fmt.Sprintf("\tDocker container state directory %q is not accessible.\n", stateFile)
-			return Unsupported, desc
-		}
-		desc += fmt.Sprintf("\tDocker container state directory is at %q and is accessible.\n", stateFile)
-		return Recommended, desc
-	} else if strings.Contains(info.ExecutionDriver, "lxc") {
-		return Supported, desc
+	stateFile := docker.DockerStateDir()
+	if !utils.FileExists(stateFile) {
+		desc += fmt.Sprintf("\tDocker container state directory %q is not accessible.\n", stateFile)
+		return Unsupported, desc
 	}
-	return Unknown, desc
+	desc += fmt.Sprintf("\tDocker container state directory is at %q and is accessible.\n", stateFile)
+	return Recommended, desc
 }
 
 func validateCgroupMounts() (string, string) {