From f152f656a05465ec8a03251dbdbaf224f3aba6a1 Mon Sep 17 00:00:00 2001
From: Brad Davidson <brad@oatmail.org>
Date: Fri, 22 Jan 2021 16:59:48 -0800
Subject: [PATCH] Replace k3s cloud provider wrangler controller with core node
 informer (#2843)

* Replace k3s cloud provider wrangler controller with core node informer

Upstream k8s has exposed an interface for cloud providers to access the
cloud controller manager's node cache and shared informer since
Kubernetes 1.9. This is used by all the other in-tree cloud providers;
we should use it too instead of running a dedicated wrangler controller.

Doing so also appears to fix an intermittent issue with the uninitialized
taint not getting cleared on nodes in CI.

Signed-off-by: Brad Davidson <brad.davidson@rancher.com>
---
 pkg/cloudprovider/cloudprovider.go | 21 ++++++++++++---------
 pkg/cloudprovider/instances.go     | 13 +++++++++++--
 2 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/pkg/cloudprovider/cloudprovider.go b/pkg/cloudprovider/cloudprovider.go
index fd2dd80db0..8e641c5a5f 100644
--- a/pkg/cloudprovider/cloudprovider.go
+++ b/pkg/cloudprovider/cloudprovider.go
@@ -1,20 +1,23 @@
 package cloudprovider
 
 import (
-	"context"
 	"io"
 
 	"github.com/rancher/k3s/pkg/version"
-	"github.com/rancher/wrangler-api/pkg/generated/controllers/core"
-	coreclient "github.com/rancher/wrangler-api/pkg/generated/controllers/core/v1"
-	"github.com/rancher/wrangler/pkg/start"
+	"k8s.io/client-go/informers"
+	informercorev1 "k8s.io/client-go/informers/core/v1"
+	"k8s.io/client-go/tools/cache"
 	cloudprovider "k8s.io/cloud-provider"
 )
 
 type k3s struct {
-	NodeCache coreclient.NodeCache
+	nodeInformer          informercorev1.NodeInformer
+	nodeInformerHasSynced cache.InformerSynced
 }
 
+var _ cloudprovider.Interface = &k3s{}
+var _ cloudprovider.InformerUser = &k3s{}
+
 func init() {
 	cloudprovider.RegisterCloudProvider(version.Program, func(config io.Reader) (cloudprovider.Interface, error) {
 		return &k3s{}, nil
@@ -22,11 +25,11 @@ func init() {
 }
 
 func (k *k3s) Initialize(clientBuilder cloudprovider.ControllerClientBuilder, stop <-chan struct{}) {
-	coreFactory := core.NewFactoryFromConfigOrDie(clientBuilder.ConfigOrDie("cloud-controller-manager"))
+}
 
-	go start.All(context.Background(), 1, coreFactory)
-
-	k.NodeCache = coreFactory.Core().V1().Node().Cache()
+func (k *k3s) SetInformers(informerFactory informers.SharedInformerFactory) {
+	k.nodeInformer = informerFactory.Core().V1().Nodes()
+	k.nodeInformerHasSynced = k.nodeInformer.Informer().HasSynced
 }
 
 func (k *k3s) Instances() (cloudprovider.Instances, bool) {
diff --git a/pkg/cloudprovider/instances.go b/pkg/cloudprovider/instances.go
index 34a13d2a10..0f8eeba9d4 100644
--- a/pkg/cloudprovider/instances.go
+++ b/pkg/cloudprovider/instances.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/pkg/errors"
 	"github.com/rancher/k3s/pkg/version"
 	"github.com/sirupsen/logrus"
 	corev1 "k8s.io/api/core/v1"
@@ -30,7 +31,11 @@ func (k *k3s) InstanceExistsByProviderID(ctx context.Context, providerID string)
 }
 
 func (k *k3s) InstanceID(ctx context.Context, nodeName types.NodeName) (string, error) {
-	_, err := k.NodeCache.Get(string(nodeName))
+	if k.nodeInformerHasSynced == nil || !k.nodeInformerHasSynced() {
+		return "", errors.New("Node informer has not synced yet")
+	}
+
+	_, err := k.nodeInformer.Lister().Get(string(nodeName))
 	if err != nil {
 		return "", fmt.Errorf("Failed to find node %s: %v", nodeName, err)
 	}
@@ -55,7 +60,11 @@ func (k *k3s) InstanceTypeByProviderID(ctx context.Context, providerID string) (
 
 func (k *k3s) NodeAddresses(ctx context.Context, name types.NodeName) ([]corev1.NodeAddress, error) {
 	addresses := []corev1.NodeAddress{}
-	node, err := k.NodeCache.Get(string(name))
+	if k.nodeInformerHasSynced == nil || !k.nodeInformerHasSynced() {
+		return nil, errors.New("Node informer has not synced yet")
+	}
+
+	node, err := k.nodeInformer.Lister().Get(string(name))
 	if err != nil {
 		return nil, fmt.Errorf("Failed to find node %s: %v", name, err)
 	}