ip-reconciler: also account for the pods IP addresses

Only mark a pod as "alive" when the pod's annotations feature the IP being de-allocated. This makes the reconciler binary *dependent* on multus, which adds these `network-status` annotations into the pod. Signed-off-by: Miguel Duarte Barroso <[email protected]>
k8snetworkplumbingwg · Jul 19, 2021 · 0b2d5c2 · 0b2d5c2
1 parent 71472dd
commit 0b2d5c2
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Showing 5 changed files with 318 additions and 46 deletions.
diff --git a/cmd/reconciler/ip_test.go b/cmd/reconciler/ip_test.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"net"
 	"strings"
@@ -12,6 +13,7 @@ import (
 	"github.com/dougbtv/whereabouts/pkg/api/v1alpha1"
 	"github.com/dougbtv/whereabouts/pkg/reconciler"
 	"github.com/dougbtv/whereabouts/pkg/types"
+	multusv1 "github.com/k8snetworkplumbingwg/network-attachment-definition-client/pkg/apis/k8s.cni.cncf.io/v1"
 
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -20,10 +22,11 @@ import (
 
 var _ = Describe("Whereabouts IP reconciler", func() {
 	const (
-		ipRange     = "10.10.10.0/16"
-		namespace   = "testns"
-		networkName = "net1"
-		podName     = "pod1"
+		firstIPInRange = "10.10.10.1"
+		ipRange        = "10.10.10.0/16"
+		namespace      = "testns"
+		networkName    = "net1"
+		podName        = "pod1"
 	)
 
 	var (
@@ -41,7 +44,8 @@ var _ = Describe("Whereabouts IP reconciler", func() {
 
 		BeforeEach(func() {
 			var err error
-			pod, err = k8sClientSet.CoreV1().Pods(namespace).Create(generatePod(namespace, podName, networkName))
+			pod, err = k8sClientSet.CoreV1().Pods(namespace).Create(
+				generatePod(namespace, podName, ipInNetwork{ip: firstIPInRange, networkName: networkName}))
 			Expect(err).NotTo(HaveOccurred())
 		})
 
@@ -94,16 +98,21 @@ var _ = Describe("Whereabouts IP reconciler", func() {
 
 	Context("multiple pods", func() {
 		const (
-			deadPodIndex = 0
-			livePodIndex = 1
-			numberOfPods = 2
+			deadPodIndex    = 0
+			livePodIndex    = 1
+			numberOfPods    = 2
+			secondIPInRange = "10.10.10.2"
 		)
 
 		var pods []v1.Pod
 
 		BeforeEach(func() {
+			ips := []string{firstIPInRange, secondIPInRange}
 			for i := 0; i < numberOfPods; i++ {
-				pod := generatePod(namespace, fmt.Sprintf("pod%d", i+1), networkName)
+				pod := generatePod(namespace, fmt.Sprintf("pod%d", i+1), ipInNetwork{
+					ip:          ips[i],
+					networkName: networkName,
+				})
 				if i == livePodIndex {
 					_, err := k8sClientSet.CoreV1().Pods(namespace).Create(pod)
 					Expect(err).NotTo(HaveOccurred())
@@ -189,13 +198,17 @@ func generateIPPoolSpec(ipRange string, namespace string, poolName string, podNa
 	}
 }
 
-func generatePod(namespace string, podName string, networks ...string) *v1.Pod {
-	networkAnnotations := map[string]string{"k8s.v1.cni.cncf.io/networks": strings.Join(networks, ",")}
+type ipInNetwork struct {
+	ip          string
+	networkName string
+}
+
+func generatePod(namespace string, podName string, ipNetworks ...ipInNetwork) *v1.Pod {
 	return &v1.Pod{
 		ObjectMeta: metav1.ObjectMeta{
 			Name:        podName,
 			Namespace:   namespace,
-			Annotations: networkAnnotations,
+			Annotations: generatePodAnnotations(ipNetworks...),
 		},
 		Spec: v1.PodSpec{
 			Containers: []v1.Container{
@@ -208,3 +221,32 @@ func generatePod(namespace string, podName string, networks ...string) *v1.Pod {
 		},
 	}
 }
+
+func generatePodAnnotations(ipNetworks ...ipInNetwork) map[string]string {
+	var networks []string
+	for _, ipNetworkInfo := range ipNetworks {
+		networks = append(networks, ipNetworkInfo.networkName)
+	}
+	networkAnnotations := map[string]string{
+		reconciler.MultusNetworkAnnotation:       strings.Join(networks, ","),
+		reconciler.MultusNetworkStatusAnnotation: generatePodNetworkStatusAnnotation(ipNetworks...),
+	}
+	return networkAnnotations
+}
+
+func generatePodNetworkStatusAnnotation(ipNetworks ...ipInNetwork) string {
+	var networkStatus []multusv1.NetworkStatus
+	for i, ipNetworkInfo := range ipNetworks {
+		networkStatus = append(networkStatus, multusv1.NetworkStatus{
+			Name:      ipNetworkInfo.networkName,
+			Interface: fmt.Sprintf("net%d", i+1),
+			IPs:       []string{ipNetworkInfo.ip},
+		})
+	}
+	networkStatusStr, err := json.Marshal(networkStatus)
+	if err != nil {
+		return ""
+	}
+
+	return string(networkStatusStr)
+}
diff --git a/pkg/reconciler/iploop.go b/pkg/reconciler/iploop.go
@@ -9,13 +9,14 @@ import (
 	"github.com/dougbtv/whereabouts/pkg/storage"
 	"github.com/dougbtv/whereabouts/pkg/storage/kubernetes"
 	"github.com/dougbtv/whereabouts/pkg/types"
+	v1 "k8s.io/api/core/v1"
 )
 
 type ReconcileLooper struct {
 	cancelFunc  func()
 	ctx         context.Context
 	k8sClient   kubernetes.Client
-	livePodRefs []string
+	livePods    map[string]podWrapper
 	orphanedIPs []OrphanedIPReservations
 }
 
@@ -33,17 +34,17 @@ func NewReconcileLooper(kubeConfigPath string) (*ReconcileLooper, error) {
 	logging.Debugf("successfully read the kubernetes configuration file located at: %s", kubeConfigPath)
 
 	ctx, cancel := context.WithTimeout(context.Background(), storage.RequestTimeout)
-	podRefs, err := getPodRefs(*k8sClient)
+	pods, err := k8sClient.ListPods()
 	if err != nil {
 		cancel()
 		return nil, err
 	}
 
 	looper := &ReconcileLooper{
-		cancelFunc:  cancel,
-		ctx:         ctx,
-		k8sClient:   *k8sClient,
-		livePodRefs: podRefs,
+		cancelFunc: cancel,
+		ctx:        ctx,
+		k8sClient:  *k8sClient,
+		livePods:   indexPods(pods),
 	}
 
 	if err := looper.findOrphanedIPsPerPool(); err != nil {
@@ -52,19 +53,6 @@ func NewReconcileLooper(kubeConfigPath string) (*ReconcileLooper, error) {
 	return looper, nil
 }
 
-func getPodRefs(k8sClient kubernetes.Client) ([]string, error) {
-	pods, err := k8sClient.ListPods()
-	if err != nil {
-		return nil, err
-	}
-
-	var podRefs []string
-	for _, pod := range pods {
-		podRefs = append(podRefs, fmt.Sprintf("%s/%s", pod.GetNamespace(), pod.GetName()))
-	}
-	return podRefs, err
-}
-
 func (rl *ReconcileLooper) findOrphanedIPsPerPool() error {
 	ipPools, err := rl.k8sClient.ListIPPools(rl.ctx)
 	if err != nil {
@@ -75,15 +63,15 @@ func (rl *ReconcileLooper) findOrphanedIPsPerPool() error {
 		orphanIP := OrphanedIPReservations{
 			Pool: pool,
 		}
-		for _, allocation := range pool.Allocations() {
-			logging.Debugf("the IP reservation: %s", allocation)
-			if allocation.PodRef == "" {
-				_ = logging.Errorf("pod ref missing for Allocations: %s", allocation)
+		for _, ipReservation := range pool.Allocations() {
+			logging.Debugf("the IP reservation: %s", ipReservation)
+			if ipReservation.PodRef == "" {
+				_ = logging.Errorf("pod ref missing for Allocations: %s", ipReservation)
 				continue
 			}
-			if !rl.isPodAlive(allocation.PodRef) {
-				logging.Debugf("pod ref %s is not listed in the live pods list", allocation.PodRef)
-				orphanIP.Allocations = append(orphanIP.Allocations, allocation)
+			if !rl.isPodAlive(ipReservation) {
+				logging.Debugf("pod ref %s is not listed in the live pods list", ipReservation.PodRef)
+				orphanIP.Allocations = append(orphanIP.Allocations, ipReservation)
 			}
 		}
 		if len(orphanIP.Allocations) > 0 {
@@ -94,15 +82,26 @@ func (rl *ReconcileLooper) findOrphanedIPsPerPool() error {
 	return nil
 }
 
-func (rl ReconcileLooper) isPodAlive(podRef string) bool {
-	for _, livePodRef := range rl.livePodRefs {
-		if podRef == livePodRef {
-			return true
+func (rl ReconcileLooper) isPodAlive(allocation types.IPReservation) bool {
+	for livePodRef, livePod := range rl.livePods {
+		if allocation.PodRef == livePodRef {
+			livePodIPs := livePod.ips
+			logging.Debugf(
+				"pod reference %s matches allocation; Allocation IP: %s; PodIPs: %s",
+				livePodRef,
+				allocation.IP.String(),
+				livePodIPs)
+			_, isFound := livePodIPs[allocation.IP.String()]
+			return isFound
 		}
 	}
 	return false
 }
 
+func composePodRef(pod v1.Pod) string {
+	return fmt.Sprintf("%s/%s", pod.GetNamespace(), pod.GetName())
+}
+
 func (rl ReconcileLooper) ReconcileIPPools() ([]types.IPReservation, error) {
 	defer rl.cancelFunc()
 

diff --git a/pkg/reconciler/iploop_test.go b/pkg/reconciler/iploop_test.go
@@ -37,8 +37,8 @@ var _ = Describe("IPReconciler", func() {
 
 	newIPReconciler := func(orphanedIPs ...OrphanedIPReservations) *ReconcileLooper {
 		reconciler := &ReconcileLooper{
-			cancelFunc: func() {},
-			ctx: context.TODO(),
+			cancelFunc:  func() {},
+			ctx:         context.TODO(),
 			orphanedIPs: orphanedIPs,
 		}
 
@@ -143,7 +143,7 @@ func generateIPPool(cidr string, podRefs ...string) whereaboutsv1alpha1.IPPool {
 
 	return whereaboutsv1alpha1.IPPool{
 		Spec: whereaboutsv1alpha1.IPPoolSpec{
-			Range: cidr,
+			Range:       cidr,
 			Allocations: allocations,
 		},
 	}
@@ -160,4 +160,4 @@ func generateIPReservation(ip string, podRef string) []types.IPReservation {
 
 func generatePodRef(namespace, podName string) string {
 	return fmt.Sprintf("%s/%s", namespace, podName)
-}
+}
diff --git a/pkg/reconciler/wrappedPod.go b/pkg/reconciler/wrappedPod.go
@@ -0,0 +1,62 @@
+package reconciler
+
+import (
+	"encoding/json"
+
+	"github.com/dougbtv/whereabouts/pkg/logging"
+	k8snetworkplumbingwgv1 "github.com/k8snetworkplumbingwg/network-attachment-definition-client/pkg/apis/k8s.cni.cncf.io/v1"
+
+	v1 "k8s.io/api/core/v1"
+)
+
+const (
+	multusInterfaceNamePrefix     = "net"
+	multusPrefixSize              = len(multusInterfaceNamePrefix)
+	MultusNetworkAnnotation       = "k8s.v1.cni.cncf.io/networks"
+	MultusNetworkStatusAnnotation = "k8s.v1.cni.cncf.io/networks-status"
+)
+
+type podWrapper struct {
+	ips map[string]void
+}
+
+type void struct{}
+
+func wrapPod(pod v1.Pod) *podWrapper {
+	return &podWrapper{
+		ips: getFlatIPSet(pod),
+	}
+}
+
+func indexPods(podList []v1.Pod) map[string]podWrapper {
+	podMap := map[string]podWrapper{}
+
+	for _, pod := range podList {
+		wrappedPod := wrapPod(pod)
+		if wrappedPod != nil {
+			podMap[composePodRef(pod)] = *wrappedPod
+		}
+	}
+	return podMap
+}
+
+func getFlatIPSet(pod v1.Pod) map[string]void {
+	var empty void
+	ipSet := map[string]void{}
+	networkStatusAnnotationValue := []byte(pod.Annotations[MultusNetworkStatusAnnotation])
+	var networkStatusList []k8snetworkplumbingwgv1.NetworkStatus
+	if err := json.Unmarshal(networkStatusAnnotationValue, &networkStatusList); err != nil {
+		_ = logging.Errorf("could not parse network annotation %s for pod: %s; error: %v", networkStatusAnnotationValue, composePodRef(pod), err)
+		return ipSet
+	}
+
+	for _, network := range networkStatusList {
+		// we're only after multus secondary interfaces
+		if network.Interface[:multusPrefixSize] == multusInterfaceNamePrefix {
+			for _, ip := range network.IPs {
+				ipSet[ip] = empty
+			}
+		}
+	}
+	return ipSet
+}