Merge pull request #4716 from elmiko/configurable-capi-version

add user configurable cluster api version

cluster-autoscaler/cloudprovider/clusterapi/README.md

@@ -180,6 +180,23 @@ the machine annotation on nodes will be `test.8s.io/machine`, the machine deleti
 annotation will be `test.k8s.io/delete-machine`, and the cluster name label will be
 `test.k8s.io/cluster-name`.
 
+## Specifying a Custom Resource Version
+
+When determining the group version for the Cluster API types, by default the autoscaler
+will look for the latest version of the group. For example, if `MachineDeployments`
+exist in the `cluster.x-k8s.io` group at versions `v1alpha1` and `v1beta1`, the
+autoscaler will choose `v1beta1`.
+
+In some cases it may be desirable to specify which version of the API the cluster
+autoscaler should use. This can be useful in debugging scenarios, or in situations
+where you have deployed multiple API versions and wish to ensure that the autoscaler
+uses a specific version.
+
+Setting the `CAPI_VERSION` environment variable will instruct the autoscaler to use
+the version specified. This works in a similar fashion as the API group environment
+variable with the exception that there is no default value. When this variable is not
+set, the autoscaler will use the behavior described above.
+
 ## Sample manifest
 
 A sample manifest that will create a deployment running the autoscaler is

cluster-autoscaler/cloudprovider/clusterapi/clusterapi_controller.go

@@ -46,7 +46,9 @@ const (
 	nodeProviderIDIndex    = "nodeProviderIDIndex"
 	defaultCAPIGroup       = "cluster.x-k8s.io"
 	// CAPIGroupEnvVar contains the environment variable name which allows overriding defaultCAPIGroup.
-	CAPIGroupEnvVar               = "CAPI_GROUP"
+	CAPIGroupEnvVar = "CAPI_GROUP"
+	// CAPIVersionEnvVar contains the environment variable name which allows overriding the Cluster API group version.
+	CAPIVersionEnvVar             = "CAPI_VERSION"
 	resourceNameMachine           = "machines"
 	resourceNameMachineSet        = "machinesets"
 	resourceNameMachineDeployment = "machinedeployments"
@@ -305,6 +307,17 @@ func getCAPIGroup() string {
 	return g
 }
 
+// getCAPIVersion returns a string the specifies the version for the API.
+// It will return either the value from the CAPI_VERSION environment variable,
+// or an empty string if the variable is not set.
+func getCAPIVersion() string {
+	v := os.Getenv(CAPIVersionEnvVar)
+	if v != "" {
+		klog.V(4).Infof("Using API Version %q", v)
+	}
+	return v
+}
+
 // newMachineController constructs a controller that watches Nodes,
 // Machines and MachineSet as they are added, updated and deleted on
 // the cluster.
@@ -415,6 +428,10 @@ func groupVersionHasResource(client discovery.DiscoveryInterface, groupVersion,
 }
 
 func getAPIGroupPreferredVersion(client discovery.DiscoveryInterface, APIGroup string) (string, error) {
+	if version := os.Getenv(CAPIVersionEnvVar); version != "" {
+		return version, nil
+	}
+
 	groupList, err := client.ServerGroups()
 	if err != nil {
 		return "", fmt.Errorf("failed to get ServerGroups: %v", err)

cluster-autoscaler/cloudprovider/clusterapi/clusterapi_controller_test.go

@@ -1369,6 +1369,26 @@ func TestControllerGetAPIVersionGroup(t *testing.T) {
 	}
 }
 
+func TestControllerGetAPIVersion(t *testing.T) {
+	expected := "v1beta1"
+	if err := os.Setenv(CAPIVersionEnvVar, expected); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	observed := getCAPIVersion()
+	if observed != expected {
+		t.Fatalf("Wrong API Version detected, expected %q, got %q", expected, observed)
+	}
+
+	if err := os.Unsetenv(CAPIVersionEnvVar); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	expected = ""
+	observed = getCAPIVersion()
+	if observed != expected {
+		t.Fatalf("Wrong API Version detected, expected %q, got %q", expected, observed)
+	}
+}
+
 func TestControllerGetAPIVersionGroupWithMachineDeployments(t *testing.T) {
 	testConfig := createMachineDeploymentTestConfig(RandomString(6), RandomString(6), RandomString(6), 1, map[string]string{
 		nodeGroupMinSizeAnnotationKey: "1",
@@ -1424,28 +1444,40 @@ func TestControllerGetAPIVersionGroupWithMachineDeployments(t *testing.T) {
 }
 
 func TestGetAPIGroupPreferredVersion(t *testing.T) {
+	customVersion := "v1"
 	testCases := []struct {
 		description      string
 		APIGroup         string
 		preferredVersion string
+		envVar           string
 		error            bool
 	}{
 		{
 			description:      "find version for default API group",
 			APIGroup:         defaultCAPIGroup,
 			preferredVersion: "v1alpha3",
+			envVar:           "",
 			error:            false,
 		},
 		{
 			description:      "find version for another API group",
 			APIGroup:         customCAPIGroup,
 			preferredVersion: "v1beta1",
+			envVar:           "",
+			error:            false,
+		},
+		{
+			description:      "find version for another API group while overriding version with env var",
+			APIGroup:         customCAPIGroup,
+			preferredVersion: customVersion,
+			envVar:           customVersion,
 			error:            false,
 		},
 		{
 			description:      "API group does not exist",
 			APIGroup:         "does.not.exist",
 			preferredVersion: "",
+			envVar:           "",
 			error:            true,
 		},
 	}
@@ -1459,11 +1491,23 @@ func TestGetAPIGroupPreferredVersion(t *testing.T) {
 				{
 					GroupVersion: fmt.Sprintf("%s/v1alpha3", defaultCAPIGroup),
 				},
+				{
+					GroupVersion: fmt.Sprintf("%s/%s", customCAPIGroup, customVersion),
+				},
 			},
 		},
 	}
 	for _, tc := range testCases {
 		t.Run(tc.description, func(t *testing.T) {
+			if tc.envVar == "" {
+				if err := os.Unsetenv(CAPIVersionEnvVar); err != nil {
+					t.Fatalf("unexpected error: %v", err)
+				}
+			} else {
+				if err := os.Setenv(CAPIVersionEnvVar, tc.envVar); err != nil {
+					t.Fatalf("unexpected error: %v", err)
+				}
+			}
 			version, err := getAPIGroupPreferredVersion(discoveryClient, tc.APIGroup)
 			if (err != nil) != tc.error {
 				t.Errorf("expected to have error: %t. Had an error: %t", tc.error, err != nil)
@@ -1473,6 +1517,10 @@ func TestGetAPIGroupPreferredVersion(t *testing.T) {
 			}
 		})
 	}
+
+	if err := os.Unsetenv(CAPIVersionEnvVar); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
 }
 
 func TestGroupVersionHasResource(t *testing.T) {