🐛 fix: ELBv2 health check for Load Balancer API

This change intents to synchronize w/ CLB the health check attributes for
API LB, and use the correct health check path when using HTTP or HTTPS.

The following target group health check attributes for ELBv2
are setting based in the CLB configuration for all protocols:

- interval: current(30) want(10)
- timeout: current(10) want(5)
- health threshold count: current(5) want(5)
- unhealthy threshold count: current(2) want(3)

When using HTTP or HTTPS, the following attributes will be fixed:

- path: current("/") want("/readyz")

*'current' is the default values set by AWS, 'want' is the value set
in the CLB.

api/v1beta2/network_types.go

@@ -27,6 +27,16 @@ const (
 	DefaultAPIServerPort = 6443
 	// DefaultAPIServerPortString defines the API server port as a string for convenience.
 	DefaultAPIServerPortString = "6443"
+	// DefaultAPIServerHealthCheckPath the API server health check path.
+	DefaultAPIServerHealthCheckPath = "/readyz"
+	// DefaultAPIServerHealthCheckIntervalSec the API server health check interval in seconds.
+	DefaultAPIServerHealthCheckIntervalSec = 10
+	// DefaultAPIServerHealthCheckTimeoutSec the API server health check timeout in seconds.
+	DefaultAPIServerHealthCheckTimeoutSec = 5
+	// DefaultAPIServerHealthThresholdCount the API server health check threshold count.
+	DefaultAPIServerHealthThresholdCount = 5
+	// DefaultAPIServerUnhealthThresholdCount the API server unhealthy check threshold count.
+	DefaultAPIServerUnhealthThresholdCount = 3
 )
 
 // NetworkStatus encapsulates AWS networking resources.

pkg/cloud/services/elb/loadbalancer.go

@@ -172,6 +172,23 @@ func (s *Service) getAPIServerLBSpec(elbName string, lbSpec *infrav1.AWSLoadBala
 		scheme = *lbSpec.Scheme
 	}
 
+	// The default API health check is TCP, allowing customization to HTTP or HTTPS when HealthCheckProtocol is set.
+	apiHealthCheckProtocol := infrav1.ELBProtocolTCP
+	if lbSpec != nil && lbSpec.HealthCheckProtocol != nil {
+		s.scope.Trace("Found API health check protocol override in the Load Balancer spec, applying it to the API Target Group", "api-server-elb", lbSpec.HealthCheckProtocol)
+		apiHealthCheckProtocol = *lbSpec.HealthCheckProtocol
+	}
+	apiHealthCheck := &infrav1.TargetGroupHealthCheck{
+		Protocol:        aws.String(apiHealthCheckProtocol.String()),
+		Port:            aws.String(infrav1.DefaultAPIServerPortString),
+		Path:            nil,
+		IntervalSeconds: aws.Int64(infrav1.DefaultAPIServerHealthCheckIntervalSec),
+		TimeoutSeconds:  aws.Int64(infrav1.DefaultAPIServerHealthCheckTimeoutSec),
+		ThresholdCount:  aws.Int64(infrav1.DefaultAPIServerHealthThresholdCount),
+	}
+	if apiHealthCheckProtocol == infrav1.ELBProtocolHTTP || apiHealthCheckProtocol == infrav1.ELBProtocolHTTPS {
+		apiHealthCheck.Path = aws.String(infrav1.DefaultAPIServerHealthCheckPath)
+	}
 	res := &infrav1.LoadBalancer{
 		Name:          elbName,
 		Scheme:        scheme,
@@ -181,14 +198,11 @@ func (s *Service) getAPIServerLBSpec(elbName string, lbSpec *infrav1.AWSLoadBala
 				Protocol: infrav1.ELBProtocolTCP,
 				Port:     infrav1.DefaultAPIServerPort,
 				TargetGroup: infrav1.TargetGroupSpec{
-					Name:     fmt.Sprintf("apiserver-target-%d", time.Now().Unix()),
-					Port:     infrav1.DefaultAPIServerPort,
-					Protocol: infrav1.ELBProtocolTCP,
-					VpcID:    s.scope.VPC().ID,
-					HealthCheck: &infrav1.TargetGroupHealthCheck{
-						Protocol: aws.String(string(infrav1.ELBProtocolTCP)),
-						Port:     aws.String(infrav1.DefaultAPIServerPortString),
-					},
+					Name:        fmt.Sprintf("apiserver-target-%d", time.Now().Unix()),
+					Port:        infrav1.DefaultAPIServerPort,
+					Protocol:    infrav1.ELBProtocolTCP,
+					VpcID:       s.scope.VPC().ID,
+					HealthCheck: apiHealthCheck,
 				},
 			},
 		},
@@ -321,6 +335,19 @@ func (s *Service) createLB(spec *infrav1.LoadBalancer, lbSpec *infrav1.AWSLoadBa
 			targetGroupInput.HealthCheckEnabled = aws.Bool(true)
 			targetGroupInput.HealthCheckProtocol = ln.TargetGroup.HealthCheck.Protocol
 			targetGroupInput.HealthCheckPort = ln.TargetGroup.HealthCheck.Port
+			targetGroupInput.UnhealthyThresholdCount = aws.Int64(infrav1.DefaultAPIServerUnhealthThresholdCount)
+			if ln.TargetGroup.HealthCheck.Path != nil {
+				targetGroupInput.HealthCheckPath = ln.TargetGroup.HealthCheck.Path
+			}
+			if ln.TargetGroup.HealthCheck.IntervalSeconds != nil {
+				targetGroupInput.HealthCheckIntervalSeconds = ln.TargetGroup.HealthCheck.IntervalSeconds
+			}
+			if ln.TargetGroup.HealthCheck.TimeoutSeconds != nil {
+				targetGroupInput.HealthCheckTimeoutSeconds = ln.TargetGroup.HealthCheck.TimeoutSeconds
+			}
+			if ln.TargetGroup.HealthCheck.ThresholdCount != nil {
+				targetGroupInput.HealthyThresholdCount = ln.TargetGroup.HealthCheck.ThresholdCount
+			}
 		}
 		s.scope.Debug("creating target group", "group", targetGroupInput, "listener", ln)
 		group, err := s.ELBV2Client.CreateTargetGroup(targetGroupInput)
@@ -1002,10 +1029,10 @@ func (s *Service) getAPIServerClassicELBSpec(elbName string) (*infrav1.LoadBalan
 		},
 		HealthCheck: &infrav1.ClassicELBHealthCheck{
 			Target:             s.getHealthCheckTarget(),
-			Interval:           10 * time.Second,
-			Timeout:            5 * time.Second,
-			HealthyThreshold:   5,
-			UnhealthyThreshold: 3,
+			Interval:           infrav1.DefaultAPIServerHealthCheckIntervalSec * time.Second,
+			Timeout:            infrav1.DefaultAPIServerHealthCheckTimeoutSec * time.Second,
+			HealthyThreshold:   infrav1.DefaultAPIServerHealthThresholdCount,
+			UnhealthyThreshold: infrav1.DefaultAPIServerUnhealthThresholdCount,
 		},
 		SecurityGroupIDs: securityGroupIDs,
 		ClassicElbAttributes: infrav1.ClassicELBAttributes{
@@ -1501,7 +1528,7 @@ func (s *Service) getHealthCheckTarget() string {
 	if controlPlaneELB != nil && controlPlaneELB.HealthCheckProtocol != nil {
 		protocol = controlPlaneELB.HealthCheckProtocol
 		if protocol.String() == infrav1.ELBProtocolHTTP.String() || protocol.String() == infrav1.ELBProtocolHTTPS.String() {
-			return fmt.Sprintf("%v:%d/readyz", protocol, infrav1.DefaultAPIServerPort)
+			return fmt.Sprintf("%v:%d%s", protocol, infrav1.DefaultAPIServerPort, infrav1.DefaultAPIServerHealthCheckPath)
 		}
 	}
 	return fmt.Sprintf("%v:%d", protocol, infrav1.DefaultAPIServerPort)