From 1c82cdc2f144d27bde82e95897c027323dca8b6d Mon Sep 17 00:00:00 2001
From: Evan Baker <rbtr@users.noreply.github.com>
Date: Wed, 12 Jan 2022 03:37:59 +0000
Subject: [PATCH 1/2] fix initialize from kube pods flow

Signed-off-by: Evan Baker <rbtr@users.noreply.github.
---
 cns/NetworkContainerContract.go | 16 +++++++++-
 cns/service/main.go             | 56 +++++++++++++++++++++------------
 2 files changed, 51 insertions(+), 21 deletions(-)

diff --git a/cns/NetworkContainerContract.go b/cns/NetworkContainerContract.go
index 6b5f396c2e..a724eaf5bc 100644
--- a/cns/NetworkContainerContract.go
+++ b/cns/NetworkContainerContract.go
@@ -2,13 +2,14 @@ package cns
 
 import (
 	"encoding/json"
-	"errors"
 	"fmt"
 	"net"
 	"strconv"
 	"strings"
 
 	"github.com/Azure/azure-container-networking/cns/types"
+	"github.com/pkg/errors"
+	corev1 "k8s.io/api/core/v1"
 )
 
 // Container Network Service DNC Contract
@@ -254,6 +255,19 @@ func NewPodInfoFromIPConfigRequest(req IPConfigRequest) (PodInfo, error) {
 	return p, nil
 }
 
+func KubePodsToPodInfoByIP(pods []corev1.Pod) (map[string]PodInfo, error) {
+	podInfoByIP := map[string]PodInfo{}
+	for i := range pods {
+		if !pods[i].Spec.HostNetwork {
+			if _, ok := podInfoByIP[pods[i].Status.PodIP]; ok {
+				return nil, errors.Wrap(ErrDuplicateIP, pods[i].Status.PodIP)
+			}
+			podInfoByIP[pods[i].Status.PodIP] = NewPodInfo("", "", pods[i].Name, pods[i].Namespace)
+		}
+	}
+	return podInfoByIP, nil
+}
+
 // MultiTenancyInfo contains encap type and id.
 type MultiTenancyInfo struct {
 	EncapType string
diff --git a/cns/service/main.go b/cns/service/main.go
index 521580b708..12fa5e43ca 100644
--- a/cns/service/main.go
+++ b/cns/service/main.go
@@ -46,6 +46,7 @@ import (
 	"github.com/Azure/azure-container-networking/store"
 	"github.com/avast/retry-go/v3"
 	"github.com/pkg/errors"
+	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/fields"
 	"k8s.io/apimachinery/pkg/types"
@@ -572,12 +573,7 @@ func main() {
 				cns.GlobalPodInfoScheme = cns.InterfaceIDPodInfoScheme
 			}
 		}
-		if cnsconfig.InitializeFromCNI {
-			logger.Printf("Initializing from CNI")
-		} else {
-			logger.Printf("Initializing from Kubernetes")
-		}
-		logger.Printf("Set GlobalPodInfoScheme %v", cns.GlobalPodInfoScheme)
+		logger.Printf("Set GlobalPodInfoScheme %v (InitializeFromCNI=%t)", cns.GlobalPodInfoScheme, cnsconfig.InitializeFromCNI)
 
 		err = InitializeCRDState(rootCtx, httpRestService, cnsconfig)
 		if err != nil {
@@ -826,7 +822,7 @@ type ncStateReconciler interface {
 
 // TODO(rbtr) where should this live??
 // InitCNS initializes cns by passing pods and a createnetworkcontainerrequest
-func initCNS(ctx context.Context, cli nodeNetworkConfigGetter, ncReconciler ncStateReconciler) error {
+func initCNS(ctx context.Context, cli nodeNetworkConfigGetter, ncReconciler ncStateReconciler, podInfoByIPProvider cns.PodInfoByIPProvider) error {
 	// Get nnc using direct client
 	nnc, err := cli.Get(ctx)
 	if err != nil {
@@ -856,13 +852,7 @@ func initCNS(ctx context.Context, cli nodeNetworkConfigGetter, ncReconciler ncSt
 	if err != nil {
 		return errors.Wrap(err, "failed to convert NNC status to network container request")
 	}
-
-	// rebuild CNS state from CNI
-	logger.Printf("initializing CNS from CNI")
-	podInfoByIPProvider, err := cnireconciler.NewCNIPodInfoProvider()
-	if err != nil {
-		return errors.Wrap(err, "failed to create CNI PodInfoProvider")
-	}
+	// rebuild CNS state
 	podInfoByIP, err := podInfoByIPProvider.PodInfoByIP()
 	if err != nil {
 		return errors.Wrap(err, "provider failed to provide PodInfoByIP")
@@ -921,11 +911,42 @@ func InitializeCRDState(ctx context.Context, httpRestService cns.HTTPService, cn
 		}
 	}()
 
+	clientset, err := kubernetes.NewForConfig(kubeConfig)
+	if err != nil {
+		return errors.Wrap(err, "failed to build clientset")
+	}
+
+	var podInfoByIPProvider cns.PodInfoByIPProvider
+	if cnsconfig.InitializeFromCNI {
+		logger.Printf("Initializing from CNI")
+		podInfoByIPProvider, err = cnireconciler.NewCNIPodInfoProvider()
+		if err != nil {
+			return errors.Wrap(err, "failed to create CNI PodInfoProvider")
+		}
+	} else {
+		logger.Printf("Initializing from Kubernetes")
+		var pods *corev1.PodList
+		pods, err = clientset.CoreV1().Pods("").List(ctx, metav1.ListOptions{
+			FieldSelector: "spec.nodeName=" + nodeName,
+		})
+		if err != nil {
+			return errors.Wrap(err, "failed to list Pods for PodInfoProvider")
+		}
+		podInfoByIPProvider = cns.PodInfoByIPProviderFunc(func() (map[string]cns.PodInfo, error) {
+			var podInfo map[string]cns.PodInfo
+			podInfo, err = cns.KubePodsToPodInfoByIP(pods.Items)
+			if err != nil {
+				return nil, errors.Wrap(err, "failed to convert Pods to PodInfoByIP")
+			}
+			return podInfo, nil
+		})
+	}
+
 	// apiserver nnc might not be registered or api server might be down and crashloop backof puts us outside of 5-10 minutes we have for
 	// aks addons to come up so retry a bit more aggresively here.
 	// will retry 10 times maxing out at a minute taking about 8 minutes before it gives up.
 	err = retry.Do(func() error {
-		err = initCNS(ctx, scopedcli, httpRestServiceImplementation)
+		err = initCNS(ctx, scopedcli, httpRestServiceImplementation, podInfoByIPProvider)
 		if err != nil {
 			logger.Errorf("[Azure CNS] Failed to init cns with err: %v", err)
 		}
@@ -957,11 +978,6 @@ func InitializeCRDState(ctx context.Context, httpRestService cns.HTTPService, cn
 		return errors.Wrap(err, "failed to create manager")
 	}
 
-	clientset, err := kubernetes.NewForConfig(kubeConfig)
-	if err != nil {
-		return errors.Wrap(err, "failed to build clientset")
-	}
-
 	// get our Node so that we can xref it against the NodeNetworkConfig's to make sure that the
 	// NNC is not stale and represents the Node we're running on.
 	node, err := clientset.CoreV1().Nodes().Get(ctx, nodeName, metav1.GetOptions{})

From 673a4ee5388538f3e4a045c4962e17942e1cc0ab Mon Sep 17 00:00:00 2001
From: Evan Baker <rbtr@users.noreply.github.com>
Date: Wed, 19 Jan 2022 23:31:38 +0000
Subject: [PATCH 2/2] move list pods inside closure

Signed-off-by: Evan Baker <rbtr@users.noreply.github.com>
---
 cns/service/main.go | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/cns/service/main.go b/cns/service/main.go
index 12fa5e43ca..f997f13904 100644
--- a/cns/service/main.go
+++ b/cns/service/main.go
@@ -46,7 +46,6 @@ import (
 	"github.com/Azure/azure-container-networking/store"
 	"github.com/avast/retry-go/v3"
 	"github.com/pkg/errors"
-	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/fields"
 	"k8s.io/apimachinery/pkg/types"
@@ -925,16 +924,14 @@ func InitializeCRDState(ctx context.Context, httpRestService cns.HTTPService, cn
 		}
 	} else {
 		logger.Printf("Initializing from Kubernetes")
-		var pods *corev1.PodList
-		pods, err = clientset.CoreV1().Pods("").List(ctx, metav1.ListOptions{
-			FieldSelector: "spec.nodeName=" + nodeName,
-		})
-		if err != nil {
-			return errors.Wrap(err, "failed to list Pods for PodInfoProvider")
-		}
 		podInfoByIPProvider = cns.PodInfoByIPProviderFunc(func() (map[string]cns.PodInfo, error) {
-			var podInfo map[string]cns.PodInfo
-			podInfo, err = cns.KubePodsToPodInfoByIP(pods.Items)
+			pods, err := clientset.CoreV1().Pods("").List(ctx, metav1.ListOptions{ //nolint:govet // ignore err shadow
+				FieldSelector: "spec.nodeName=" + nodeName,
+			})
+			if err != nil {
+				return nil, errors.Wrap(err, "failed to list Pods for PodInfoProvider")
+			}
+			podInfo, err := cns.KubePodsToPodInfoByIP(pods.Items)
 			if err != nil {
 				return nil, errors.Wrap(err, "failed to convert Pods to PodInfoByIP")
 			}