OpenStack: Filter fixed IP addresses with CIDR notation

This allows filtering the fixed IP addresses returned by the OpenStack
compute API with a filter defined as CIDR notation.

When specifying the filter then the first fixed IP address matching the
CIDR notation will be returned.

If no filter is specified then the first found IP will be returned.

etcd-manager/cmd/etcd-manager/BUILD.bazel

@@ -1,4 +1,4 @@
-load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library", "go_test")
 
 go_library(
     name = "etcd-manager_lib",
@@ -40,3 +40,9 @@ go_binary(
     embed = [":etcd-manager_lib"],
     visibility = ["//visibility:public"],
 )
+
+go_test(
+    name = "etcd-manager_test",
+    srcs = ["main_test.go"],
+    embed = [":etcd-manager_lib"],
+)

etcd-manager/cmd/etcd-manager/main.go

@@ -101,6 +101,8 @@ func main() {
 	var volumeTags stringSliceFlag
 	flag.Var(&volumeTags, "volume-tag", "tag which volume is required to have")
 
+	flag.StringVar(&o.NetworkCIDR, "network-cidr", o.NetworkCIDR, "filter for a specific IP address by network CIDR (OpenStack only)")
+
 	flag.Parse()
 
 	o.VolumeTags = volumeTags
@@ -162,6 +164,9 @@ type EtcdManagerOptions struct {
 
 	// EtcdManagerMetricsPort allows exposing statistics from etcd-manager
 	EtcdManagerMetricsPort int
+
+	// NetworkCIDR allows filtering for a specific IP address by network CIDR (OpenStack only)
+	NetworkCIDR string
 }
 
 // InitDefaults populates the default flag values
@@ -202,6 +207,19 @@ func RunEtcdManager(o *EtcdManagerOptions) error {
 		return fmt.Errorf("backup-store is required")
 	}
 
+	var networkCIDR *net.IPNet
+	if o.NetworkCIDR != "" {
+		if o.VolumeProviderID != "openstack" {
+			return fmt.Errorf("network-cidr is only supported with provider 'openstack'")
+		}
+
+		var err error
+		_, networkCIDR, err = net.ParseCIDR(o.NetworkCIDR)
+		if err != nil {
+			return fmt.Errorf("parsing network-cidr: %w", err)
+		}
+	}
+
 	backupInterval, err := time.ParseDuration(o.BackupInterval)
 	if err != nil {
 		return fmt.Errorf("invalid backup-interval duration %q", o.BackupInterval)
@@ -244,7 +262,7 @@ func RunEtcdManager(o *EtcdManagerOptions) error {
 			discoveryProvider = gceVolumeProvider
 
 		case "openstack":
-			osVolumeProvider, err := openstack.NewOpenstackVolumes(o.ClusterName, o.VolumeTags, o.NameTag)
+			osVolumeProvider, err := openstack.NewOpenstackVolumes(o.ClusterName, o.VolumeTags, o.NameTag, networkCIDR)
 			if err != nil {
 				fmt.Fprintf(os.Stderr, "%v\n", err)
 				os.Exit(1)

etcd-manager/cmd/etcd-manager/main_test.go

@@ -0,0 +1,66 @@
+/*
+Copyright 2022 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 main
+
+import (
+	"fmt"
+	"net"
+	"reflect"
+	"testing"
+)
+
+func getTestData(networkCIDR string, volumeProviderID string) *EtcdManagerOptions {
+	var o EtcdManagerOptions
+	o.InitDefaults()
+
+	o.ClusterName = "test"
+	o.BackupStorePath = "s3://test"
+
+	o.NetworkCIDR = networkCIDR
+	o.VolumeProviderID = volumeProviderID
+
+	return &o
+}
+
+func assertTestResults(t *testing.T, err error, expected interface{}, actual interface{}) {
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+
+	if !reflect.DeepEqual(expected, actual) {
+		t.Fatalf("expected '%+v', but got '%+v'", expected, actual)
+	}
+}
+
+func TestRunEtcdManagerReturnsNetworkCIDROnlySupportedWithOpenstack(t *testing.T) {
+	expectedErr := fmt.Errorf("network-cidr is only supported with provider 'openstack'")
+	o := getTestData("192.168.0.0/16", "aws")
+
+	actualErr := RunEtcdManager(o)
+
+	assertTestResults(t, nil, expectedErr, actualErr)
+}
+
+func TestRunEtcdManagerReturnsErrorOnInvalidCIDR(t *testing.T) {
+	invalidCIDR := "192.168.0.0/123"
+	expectedErr := fmt.Errorf("parsing network-cidr: %w", &net.ParseError{Type: "CIDR address", Text: invalidCIDR})
+	o := getTestData(invalidCIDR, "openstack")
+
+	actualErr := RunEtcdManager(o)
+
+	assertTestResults(t, nil, expectedErr, actualErr)
+}

etcd-manager/pkg/volumes/openstack/BUILD.bazel

@@ -31,7 +31,10 @@ go_library(
 
 go_test(
     name = "openstack_test",
-    srcs = ["volumes_test.go"],
+    srcs = [
+        "util_test.go",
+        "volumes_test.go",
+    ],
     data = glob(["testdata/**"]),
     embed = [":openstack"],
     deps = [

etcd-manager/pkg/volumes/openstack/discovery.go

@@ -52,7 +52,7 @@ func (os *OpenstackVolumes) Poll() (map[string]discovery.Node, error) {
 		node := discovery.Node{
 			ID: volume.EtcdName,
 		}
-		address, err := GetServerFixedIP(server.Addresses, server.Name)
+		address, err := GetServerFixedIP(server.Addresses, server.Name, os.networkCIDR)
 		if err != nil {
 			klog.Warningf("Could not find servers fixed ip %s: %v", server.Name, err)
 			continue

etcd-manager/pkg/volumes/openstack/util.go

@@ -18,6 +18,7 @@ package openstack
 
 import (
 	"fmt"
+	"net"
 )
 
 const (
@@ -26,14 +27,17 @@ const (
 	openstackAddress        = "addr"
 )
 
-func GetServerFixedIP(addrs map[string]interface{}, name string) (poolAddress string, err error) {
+func GetServerFixedIP(addrs map[string]interface{}, name string, networkCIDR *net.IPNet) (poolAddress string, err error) {
 	for _, address := range addrs {
 		if addresses, ok := address.([]interface{}); ok {
 			for _, addr := range addresses {
 				addrMap := addr.(map[string]interface{})
 				if addrType, ok := addrMap[openstackExternalIPType]; ok && addrType == openstackAddressFixed {
 					if fixedIP, ok := addrMap[openstackAddress]; ok {
 						if fixedIPStr, ok := fixedIP.(string); ok {
+							if networkCIDR != nil && !networkCIDR.Contains(net.ParseIP(fixedIPStr)) {
+								continue
+							}
 							return fixedIPStr, nil
 						}
 					}

etcd-manager/pkg/volumes/openstack/util_test.go

@@ -0,0 +1,131 @@
+/*
+Copyright 2022 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 openstack
+
+import (
+	"fmt"
+	"net"
+	"testing"
+)
+
+type TestData struct {
+	clusterName string
+	ips         []string
+	addrs       map[string]interface{}
+}
+
+func getTestData() *TestData {
+	ips := []string{
+		"10.135.1.1",
+		"2001:db8::1:0",
+		"192.168.1.1",
+		"192.168.2.1",
+	}
+
+	addrs := map[string]interface{}{
+		"test_network_1": []interface{}{
+			map[string]interface{}{
+				"OS-EXT-IPS-MAC:mac_addr": "00:00:00:00:00:01",
+				"OS-EXT-IPS:type":         "fixed",
+				"addr":                    ips[0],
+				"version":                 "4",
+			},
+			map[string]interface{}{
+				"OS-EXT-IPS-MAC:mac_addr": "00:00:00:00:00:02",
+				"OS-EXT-IPS:type":         "fixed",
+				"addr":                    ips[1],
+				"version":                 "6",
+			},
+		},
+		"test_network_2": []interface{}{
+			map[string]interface{}{
+				"OS-EXT-IPS-MAC:mac_addr": "00:00:00:00:00:03",
+				"OS-EXT-IPS:type":         "fixed",
+				"addr":                    ips[2],
+				"version":                 "4",
+			},
+			map[string]interface{}{
+				"OS-EXT-IPS-MAC:mac_addr": "00:00:00:00:00:04",
+				"OS-EXT-IPS:type":         "fixed",
+				"addr":                    ips[3],
+				"version":                 "4",
+			},
+		},
+	}
+
+	return &TestData{
+		clusterName: "test",
+		ips:         ips,
+		addrs:       addrs,
+	}
+}
+
+func TestReturnErrorOnEmptyAddresses(t *testing.T) {
+	td := getTestData()
+	td.addrs = map[string]interface{}{}
+
+	expectedErr := fmt.Errorf("failed to find Fixed IP address for server %s", td.clusterName)
+
+	_, actualErr := GetServerFixedIP(td.addrs, td.clusterName, nil)
+
+	assertTestResults(t, nil, fmt.Sprintf("%+v", expectedErr), fmt.Sprintf("%+v", actualErr))
+}
+
+func TestReturnFirstFixedIP(t *testing.T) {
+	td := getTestData()
+	expectedIP := td.ips[0]
+
+	actualIP, err := GetServerFixedIP(td.addrs, td.clusterName, nil)
+
+	assertTestResults(t, err, expectedIP, actualIP)
+}
+
+func TestReturnErrorOnNonMatchingCIDR(t *testing.T) {
+	td := getTestData()
+
+	_, cidr, _ := net.ParseCIDR("172.16.0.0/16")
+
+	expectedErr := fmt.Errorf("failed to find Fixed IP address for server %s", td.clusterName)
+
+	_, actualErr := GetServerFixedIP(td.addrs, td.clusterName, cidr)
+
+	assertTestResults(t, nil, expectedErr, actualErr)
+}
+
+func TestReturnFirstIPv4MatchingCIDR(t *testing.T) {
+	td := getTestData()
+
+	_, cidr, _ := net.ParseCIDR("192.168.2.0/24")
+
+	expectedIP := td.ips[3]
+
+	actualIP, err := GetServerFixedIP(td.addrs, td.clusterName, cidr)
+
+	assertTestResults(t, err, expectedIP, actualIP)
+}
+
+func TestReturnFirstIPv6MatchingCIDR(t *testing.T) {
+	td := getTestData()
+
+	_, cidr, _ := net.ParseCIDR("2001:db8::/64")
+
+	expectedIP := td.ips[1]
+
+	actualIP, err := GetServerFixedIP(td.addrs, td.clusterName, cidr)
+
+	assertTestResults(t, err, expectedIP, actualIP)
+}

etcd-manager/pkg/volumes/openstack/volumes.go

@@ -73,6 +73,7 @@ type OpenstackVolumes struct {
 
 	matchTagKeys []string
 	matchTags    map[string]string
+	networkCIDR  *net.IPNet
 
 	computeClient *gophercloud.ServiceClient
 	volumeClient  *gophercloud.ServiceClient
@@ -96,7 +97,7 @@ type MetadataService struct {
 var _ volumes.Volumes = &OpenstackVolumes{}
 
 // NewOpenstackVolumes builds a OpenstackVolume
-func NewOpenstackVolumes(clusterName string, volumeTags []string, nameTag string) (*OpenstackVolumes, error) {
+func NewOpenstackVolumes(clusterName string, volumeTags []string, nameTag string, networkCIDR *net.IPNet) (*OpenstackVolumes, error) {
 
 	metadata, err := getLocalMetadata()
 	if err != nil {
@@ -108,6 +109,7 @@ func NewOpenstackVolumes(clusterName string, volumeTags []string, nameTag string
 		meta:        metadata,
 		matchTags:   make(map[string]string),
 		nameTag:     nameTag,
+		networkCIDR: networkCIDR,
 	}
 
 	for _, volumeTag := range volumeTags {
@@ -368,7 +370,7 @@ func (stack *OpenstackVolumes) discoverTags() error {
 		if mc.ObserveRequest(err) != nil {
 			return fmt.Errorf("failed to retrieve server information from cloud: %v", err)
 		}
-		ip, err := GetServerFixedIP(extendedServer.Addresses, extendedServer.Name)
+		ip, err := GetServerFixedIP(extendedServer.Addresses, extendedServer.Name, stack.networkCIDR)
 		if err != nil {
 			return fmt.Errorf("error querying InternalIP from name: %v", err)
 		}