Follow up for 3691 [TargetGroupBindings can now manipulate target groups from different aws accounts]

apis/elbv2/v1alpha1/targetgroupbinding_types.go

@@ -128,6 +128,14 @@ type TargetGroupBindingSpec struct {
 	// networking provides the networking setup for ELBV2 LoadBalancer to access targets in TargetGroup.
 	// +optional
 	Networking *TargetGroupBindingNetworking `json:"networking,omitempty"`
+
+	// IAM Role ARN to assume when calling AWS APIs. Useful if the target group is in a different AWS account
+	// +optional
+	IamRoleArnToAssume string `json:"iamRoleArnToAssume,omitempty"`
+
+	// IAM Role ARN to assume when calling AWS APIs. Needed to assume a role in another account and prevent the confused deputy problem. https://docs.aws.amazon.com/IAM/latest/UserGuide/confused-deputy.html
+	// +optional
+	AssumeRoleExternalId string `json:"assumeRoleExternalId,omitempty"`
 }
 
 // TargetGroupBindingStatus defines the observed state of TargetGroupBinding

apis/elbv2/v1beta1/targetgroupbinding_types.go

@@ -160,11 +160,11 @@ type TargetGroupBindingSpec struct {
 
 	// IAM Role ARN to assume when calling AWS APIs. Useful if the target group is in a different AWS account
 	// +optional
-	IamRoleArnToAssume string `json:"-"` // `json:"iamRoleArnToAssume,omitempty"`
+	IamRoleArnToAssume string `json:"iamRoleArnToAssume,omitempty"`
 
 	// IAM Role ARN to assume when calling AWS APIs. Needed to assume a role in another account and prevent the confused deputy problem. https://docs.aws.amazon.com/IAM/latest/UserGuide/confused-deputy.html
 	// +optional
-	AssumeRoleExternalId string `json:"-"` // `json:"assumeRoleExternalId,omitempty"`
+	AssumeRoleExternalId string `json:"assumeRoleExternalId,omitempty"`
 }
 
 // TargetGroupBindingStatus defines the observed state of TargetGroupBinding

config/crd/bases/elbv2.k8s.aws_targetgroupbindings.yaml

@@ -65,6 +65,15 @@ spec:
           spec:
             description: TargetGroupBindingSpec defines the desired state of TargetGroupBinding
             properties:
+              assumeRoleExternalId:
+                description: IAM Role ARN to assume when calling AWS APIs. Needed
+                  to assume a role in another account and prevent the confused deputy
+                  problem. https://docs.aws.amazon.com/IAM/latest/UserGuide/confused-deputy.html
+                type: string
+              iamRoleArnToAssume:
+                description: IAM Role ARN to assume when calling AWS APIs. Useful
+                  if the target group is in a different AWS account
+                type: string
               multiClusterTargetGroup:
                 description: MultiClusterTargetGroup Denotes if the TargetGroup is
                   shared among multiple clusters
@@ -242,6 +251,15 @@ spec:
           spec:
             description: TargetGroupBindingSpec defines the desired state of TargetGroupBinding
             properties:
+              assumeRoleExternalId:
+                description: IAM Role ARN to assume when calling AWS APIs. Needed
+                  to assume a role in another account and prevent the confused deputy
+                  problem. https://docs.aws.amazon.com/IAM/latest/UserGuide/confused-deputy.html
+                type: string
+              iamRoleArnToAssume:
+                description: IAM Role ARN to assume when calling AWS APIs. Useful
+                  if the target group is in a different AWS account
+                type: string
               ipAddressType:
                 description: ipAddressType specifies whether the target group is of
                   type IPv4 or IPv6. If unspecified, it will be automatically inferred.

docs/guide/targetgroupbinding/spec.md

@@ -55,15 +55,6 @@ Kubernetes meta/v1.ObjectMeta
 <table>
 <tr><td><code>annotations</code></td><td>
 
-<table>
-<tr><td><code>alb.ingress.kubernetes.io/IamRoleArnToAssume</code><br><i>string</i></td>
-<td><i>(Optional)</i> In case the target group is in a differet AWS account, you put here the role that needs to be assumed in order to manipulate the target group.
-</td></tr>
-<tr><td><code>alb.ingress.kubernetes.io/AssumeRoleExternalId</code><br><i>string</i></td>
-<td><i>(Optional)</i> The external ID for the assume role operation. Optional, but recommended. It helps you to prevent the <a href="https://docs.aws.amazon.com/IAM/latest/UserGuide/confused-deputy.html" target="_blank">confused deputy problem</a>.
-</td></tr>
-</table>
-
 <tr><td colspan=2>
 Refer to the Kubernetes API documentation for the other fields of the
 <code>metadata</code> field.

docs/guide/targetgroupbinding/targetgroupbinding.md

@@ -112,10 +112,108 @@ spec:
 ### AssumeRole
 
 Sometimes the AWS LoadBalancer controller needs to manipulate target groups from different AWS accounts.
-The way to do that is assuming a role from such account. There are annotations that can help you with that:
+The way to do that is assuming a role from such an account. The following spec fields help you with that.
 
-* `alb.ingress.kubernetes.io/IamRoleArnToAssume`: the ARN that you need to assume
-* `alb.ingress.kubernetes.io/AssumeRoleExternalId`: the external ID for the assume role operation. Optional, but recommended. It helps you to prevent the confused deputy problem ( https://docs.aws.amazon.com/IAM/latest/UserGuide/confused-deputy.html )
+* `iamRoleArnToAssume`: the ARN that you need to assume
+* `assumeRoleExternalId`: the external ID for the assume role operation. Optional, but recommended. It helps you to prevent the confused deputy problem ( https://docs.aws.amazon.com/IAM/latest/UserGuide/confused-deputy.html )
+
+
+```yaml
+apiVersion: elbv2.k8s.aws/v1beta1
+kind: TargetGroupBinding
+metadata:
+  name: peered-tg
+  namespace: nlb-game-2048-1
+spec:
+  assumeRoleExternalId: very-secret-string-2
+  iamRoleArnToAssume: arn:aws:iam::155642222660:role/tg-management-role
+  networking:
+    ingress:
+    - from:
+      - securityGroup:
+          groupID: sg-0b6a41a2fd959623f
+      ports:
+      - port: 80
+        protocol: TCP
+  serviceRef:
+    name: service-2048
+    port: 80
+  targetGroupARN: arn:aws:elasticloadbalancing:us-west-2:155642222660:targetgroup/peered-tg/6a4ecf7bfae473c1
+```
+
+In the following examples, we will refer to Cluster Owner (CO) and Target Group Owner (TGO) accounts.
+
+First, in the TGO account creates a role that will allow the AWS LBC in the CO account to assume it.
+For improved security, we only allow the AWS LBC role in CO account to assume the role.
+
+```json
+{
+    "Version": "2012-10-17",
+    "Statement": [
+        {
+            "Sid": "",
+            "Effect": "Allow",
+            "Principal": {
+                "AWS": "arn:aws:iam::565768096483:role/eksctl-awslbc-loadtest-addon-iamserviceaccoun-Role1-13RdJCMqV6p2"
+            },
+            "Action": "sts:AssumeRole",
+            "Condition": {
+                "StringEquals": {
+                    "sts:ExternalId": "very-secret-string"
+                }
+            }
+        }
+    ]
+}
+```
+
+Next, still in the TGO account we need to add the following permissions to the Role created in the first step.
+
+```json
+{
+  "Version": "2012-10-17",
+  "Statement": [
+    {
+      "Sid": "VisualEditor0",
+      "Effect": "Allow",
+      "Action": [
+        "elasticloadbalancing:RegisterTargets",
+        "elasticloadbalancing:DeregisterTargets"
+      ],
+      "Resource": [
+        "arn:aws:elasticloadbalancing:us-west-2:155642222660:targetgroup/tg1/*",
+        "arn:aws:elasticloadbalancing:us-west-2:155642222660:targetgroup/tg2/*"
+        // add more here //
+      ]
+    },
+    {
+      "Sid": "VisualEditor1",
+      "Effect": "Allow",
+      "Action": [
+        "elasticloadbalancing:DescribeTargetGroups",
+        "elasticloadbalancing:DescribeTargetHealth"
+      ],
+      "Resource": "*"
+    }
+  ]
+}
+```
+
+
+Next, in the CO account, we need to allow the AWS LBC to perform the AssumeRole call.
+By default, this permission is not a part of the standard IAM policy that is vended with the LBC installation scripts.
+For improved security, it is possible to scope the AssumeRole permissions down to only roles that you know ahead of time the
+LBC will need to Assume.
+
+```json
+        {
+            "Effect": "Allow",
+            "Action": [
+                "sts:AssumeRole"
+            ],
+            "Resource": "*"
+        }
+```
 
 
 ## Sample YAML
@@ -125,10 +223,9 @@ apiVersion: elbv2.k8s.aws/v1beta1
 kind: TargetGroupBinding
 metadata:
   name: my-tgb
-  annotations:
-    alb.ingress.kubernetes.io/IamRoleArnToAssume: "arn:aws:iam::999999999999:role/alb-controller-policy-to-assume"
-    alb.ingress.kubernetes.io/AssumeRoleExternalId: "some-magic-string"
 spec:
+  iamRoleArnToAssume: "arn:aws:iam::999999999999:role/alb-controller-policy-to-assume"
+  assumeRoleExternalId: "some-magic-string"
   ...
 ```
 

go.sum

@@ -60,6 +60,7 @@ github.com/aws/aws-sdk-go-v2/service/ec2 v1.173.0 h1:ta62lid9JkIpKZtZZXSj6rP2AqY
 github.com/aws/aws-sdk-go-v2/service/ec2 v1.173.0/go.mod h1:o6QDjdVKpP5EF0dp/VlvqckzuSDATr1rLdHt3A5m0YY=
 github.com/aws/aws-sdk-go-v2/service/elasticloadbalancingv2 v1.43.1 h1:L9Wt9zgtoYKIlaeFTy+EztGjL4oaXBBGtVXA+jaeYko=
 github.com/aws/aws-sdk-go-v2/service/elasticloadbalancingv2 v1.43.1/go.mod h1:yxzLdxt7bVGvIOPYIKFtiaJCJnx2ChlIIvlhW4QgI6M=
+github.com/aws/aws-sdk-go-v2/service/iam v1.36.3/go.mod h1:HSvujsK8xeEHMIB18oMXjSfqaN9cVqpo/MtHJIksQRk=
 github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v1.11.3 h1:dT3MqvGhSoaIhRseqw2I0yH81l7wiR2vjs57O51EAm8=
 github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v1.11.3/go.mod h1:GlAeCkHwugxdHaueRr4nhPuY+WW+gR8UjlcqzPr1SPI=
 github.com/aws/aws-sdk-go-v2/service/internal/presigned-url v1.11.17 h1:HGErhhrxZlQ044RiM+WdoZxp0p+EGM62y3L6pwA4olE=

helm/aws-load-balancer-controller/crds/crds.yaml

@@ -317,6 +317,15 @@ spec:
           spec:
             description: TargetGroupBindingSpec defines the desired state of TargetGroupBinding
             properties:
+              assumeRoleExternalId:
+                description: IAM Role ARN to assume when calling AWS APIs. Needed
+                  to assume a role in another account and prevent the confused deputy
+                  problem. https://docs.aws.amazon.com/IAM/latest/UserGuide/confused-deputy.html
+                type: string
+              iamRoleArnToAssume:
+                description: IAM Role ARN to assume when calling AWS APIs. Useful
+                  if the target group is in a different AWS account
+                type: string
               multiClusterTargetGroup:
                 description: MultiClusterTargetGroup Denotes if the TargetGroup is
                   shared among multiple clusters
@@ -494,6 +503,15 @@ spec:
           spec:
             description: TargetGroupBindingSpec defines the desired state of TargetGroupBinding
             properties:
+              assumeRoleExternalId:
+                description: IAM Role ARN to assume when calling AWS APIs. Needed
+                  to assume a role in another account and prevent the confused deputy
+                  problem. https://docs.aws.amazon.com/IAM/latest/UserGuide/confused-deputy.html
+                type: string
+              iamRoleArnToAssume:
+                description: IAM Role ARN to assume when calling AWS APIs. Useful
+                  if the target group is in a different AWS account
+                type: string
               ipAddressType:
                 description: ipAddressType specifies whether the target group is of
                   type IPv4 or IPv6. If unspecified, it will be automatically inferred.

main.go

@@ -90,7 +90,7 @@ func main() {
 		awsMetricsCollector = awsmetrics.NewCollector(metrics.Registry)
 	}
 
-	cloud, err := aws.NewCloud(controllerCFG.AWSConfig, awsMetricsCollector, ctrl.Log, nil)
+	cloud, err := aws.NewCloud(controllerCFG.AWSConfig, controllerCFG.ClusterName, awsMetricsCollector, ctrl.Log, nil)
 	if err != nil {
 		setupLog.Error(err, "unable to initialize AWS cloud")
 		os.Exit(1)

pkg/aws/aws_config.go

@@ -0,0 +1,81 @@
+package aws
+
+import (
+	"context"
+	"github.com/aws/aws-sdk-go-v2/aws"
+	awsmiddleware "github.com/aws/aws-sdk-go-v2/aws/middleware"
+	"github.com/aws/aws-sdk-go-v2/aws/ratelimit"
+	"github.com/aws/aws-sdk-go-v2/aws/retry"
+	"github.com/aws/aws-sdk-go-v2/config"
+	"github.com/aws/aws-sdk-go-v2/feature/ec2/imds"
+	smithymiddleware "github.com/aws/smithy-go/middleware"
+	"sigs.k8s.io/aws-load-balancer-controller/pkg/aws/throttle"
+	awsmetrics "sigs.k8s.io/aws-load-balancer-controller/pkg/metrics/aws"
+	"sigs.k8s.io/aws-load-balancer-controller/pkg/version"
+)
+
+const (
+	userAgent = "elbv2.k8s.aws"
+)
+
+func NewAWSConfigGenerator(cfg CloudConfig, ec2IMDSEndpointMode imds.EndpointModeState, metricsCollector *awsmetrics.Collector) AWSConfigGenerator {
+	return &awsConfigGeneratorImpl{
+		cfg:                 cfg,
+		ec2IMDSEndpointMode: ec2IMDSEndpointMode,
+		metricsCollector:    metricsCollector,
+	}
+
+}
+
+// AWSConfigGenerator is responsible for generating an aws config based on the running environment
+type AWSConfigGenerator interface {
+	GenerateAWSConfig(optFns ...func(*config.LoadOptions) error) (aws.Config, error)
+}
+
+type awsConfigGeneratorImpl struct {
+	cfg                 CloudConfig
+	ec2IMDSEndpointMode imds.EndpointModeState
+	metricsCollector    *awsmetrics.Collector
+}
+
+func (gen *awsConfigGeneratorImpl) GenerateAWSConfig(optFns ...func(*config.LoadOptions) error) (aws.Config, error) {
+
+	defaultOpts := []func(*config.LoadOptions) error{
+		config.WithRegion(gen.cfg.Region),
+		config.WithRetryer(func() aws.Retryer {
+			return retry.NewStandard(func(o *retry.StandardOptions) {
+				o.RateLimiter = ratelimit.None
+				o.MaxAttempts = gen.cfg.MaxRetries
+			})
+		}),
+		config.WithEC2IMDSEndpointMode(gen.ec2IMDSEndpointMode),
+		config.WithAPIOptions([]func(stack *smithymiddleware.Stack) error{
+			awsmiddleware.AddUserAgentKeyValue(userAgent, version.GitVersion),
+		}),
+	}
+
+	defaultOpts = append(defaultOpts, optFns...)
+
+	awsConfig, err := config.LoadDefaultConfig(context.TODO(),
+		defaultOpts...,
+	)
+
+	if err != nil {
+		return aws.Config{}, err
+	}
+
+	if gen.cfg.ThrottleConfig != nil {
+		throttler := throttle.NewThrottler(gen.cfg.ThrottleConfig)
+		awsConfig.APIOptions = append(awsConfig.APIOptions, func(stack *smithymiddleware.Stack) error {
+			return throttle.WithSDKRequestThrottleMiddleware(throttler)(stack)
+		})
+	}
+
+	if gen.metricsCollector != nil {
+		awsConfig.APIOptions = awsmetrics.WithSDKMetricCollector(gen.metricsCollector, awsConfig.APIOptions)
+	}
+
+	return awsConfig, nil
+}
+
+var _ AWSConfigGenerator = &awsConfigGeneratorImpl{}