Refactor ENI limit struct

Makefile

@@ -192,10 +192,15 @@ generate:
 	go generate -x ./...
 	$(MAKE) format
 
-# Generate descriptors for supported ENI configurations.
+# Generate limit file go code
 generate-limits: GOOS=
 generate-limits:
-	go run pkg/awsutils/gen_vpc_ip_limits.go
+	go run scripts/gen_vpc_ip_limits.go
+
+# Generate eni-max-pods.txt file for EKS AMI
+generate-max-pods: GOOS=
+generate-max-pods: 
+	GENERATE_MAX_PODS=true go run scripts/gen_vpc_ip_limits.go
 
 # Fetch the CNI plugins
 plugins: FETCH_VERSION=0.8.6

pkg/awsutils/awsutils.go

@@ -151,8 +151,8 @@ type APIs interface {
 	// GetPrimaryENI returns the primary ENI
 	GetPrimaryENI() string
 
-	// GetENIipLimit return IP address limit per ENI based on EC2 instance type
-	GetENIipLimit() (int, error)
+	// GetENIIPv4Limit return IP address limit per ENI based on EC2 instance type
+	GetENIIPv4Limit() (int, error)
 
 	// GetENILimit returns the number of ENIs that can be attached to an instance
 	GetENILimit() (int, error)
@@ -199,6 +199,12 @@ type ENIMetadata struct {
 	IPv4Addresses []*ec2.NetworkInterfacePrivateIpAddress
 }
 
+// InstanceTypeLimits keeps track of limits for an instance type
+type InstanceTypeLimits struct {
+	ENILimit  int64
+	IPv4Limit int64
+}
+
 func (eni ENIMetadata) PrimaryIPv4Address() string {
 	for _, addr := range eni.IPv4Addresses {
 		if aws.BoolValue(addr.Primary) {
@@ -1170,19 +1176,19 @@ func (cache *EC2InstanceMetadataCache) AllocIPAddress(eniID string) error {
 	return nil
 }
 
-// GetENIipLimit return IP address limit per ENI based on EC2 instance type
-func (cache *EC2InstanceMetadataCache) GetENIipLimit() (int, error) {
-	ipLimit, ok := InstanceIPsAvailable[cache.instanceType]
+// GetENIIPv4Limit return IP address limit per ENI based on EC2 instance type
+func (cache *EC2InstanceMetadataCache) GetENIIPv4Limit() (int, error) {
+	eniLimits, ok := InstanceNetworkingLimits[cache.instanceType]
 	if !ok {
 		log.Errorf("Failed to get ENI IP limit due to unknown instance type %s", cache.instanceType)
 		return 0, errors.New(UnknownInstanceType)
 	}
-	return ipLimit - 1, nil
+	return int(eniLimits.IPv4Limit - 1), nil
 }
 
 // GetENILimit returns the number of ENIs can be attached to an instance
 func (cache *EC2InstanceMetadataCache) GetENILimit() (int, error) {
-	eniLimit, ok := InstanceENIsAvailable[cache.instanceType]
+	eniLimits, ok := InstanceNetworkingLimits[cache.instanceType]
 	if !ok {
 		// Fetch from EC2 API
 		describeInstanceTypesInput := &ec2.DescribeInstanceTypesInput{InstanceTypes: []*string{aws.String(cache.instanceType)}}
@@ -1194,23 +1200,26 @@ func (cache *EC2InstanceMetadataCache) GetENILimit() (int, error) {
 		info := output.InstanceTypes[0]
 		// Ignore any missing values
 		instanceType := aws.StringValue(info.InstanceType)
-		eniLimit = int(aws.Int64Value(info.NetworkInfo.MaximumNetworkInterfaces))
-		ipLimit := int(aws.Int64Value(info.NetworkInfo.Ipv4AddressesPerInterface))
-		if instanceType != "" && eniLimit > 0 && ipLimit > 0 {
-			InstanceENIsAvailable[instanceType] = eniLimit
-			InstanceIPsAvailable[instanceType] = ipLimit
+		eniLimit := aws.Int64Value(info.NetworkInfo.MaximumNetworkInterfaces)
+		ipv4Limit := aws.Int64Value(info.NetworkInfo.Ipv4AddressesPerInterface)
+		if instanceType != "" && eniLimit > 0 && ipv4Limit > 0 {
+			eniLimits = InstanceTypeLimits{
+				ENILimit:  eniLimit,
+				IPv4Limit: ipv4Limit,
+			}
+			InstanceNetworkingLimits[instanceType] = eniLimits
 		} else {
 			return 0, errors.New(fmt.Sprintf("%s: %s", UnknownInstanceType, cache.instanceType))
 		}
 	}
-	return eniLimit, nil
+	return int(eniLimits.ENILimit), nil
 }
 
 // AllocIPAddresses allocates numIPs of IP address on an ENI
 func (cache *EC2InstanceMetadataCache) AllocIPAddresses(eniID string, numIPs int) error {
 	var needIPs = numIPs
 
-	ipLimit, err := cache.GetENIipLimit()
+	ipLimit, err := cache.GetENIIPv4Limit()
 	if err != nil {
 		awsUtilsErrInc("UnknownInstanceType", err)
 		return err

pkg/awsutils/awsutils_test.go

@@ -701,7 +701,9 @@ func TestDescribeInstanceTypes(t *testing.T) {
 	value, err := ins.GetENILimit()
 	assert.NoError(t, err)
 	assert.Equal(t, 9, value)
-	assert.Equal(t, 99, InstanceIPsAvailable[ins.instanceType])
+	pv4Limit, err := ins.GetENIIPv4Limit()
+	assert.NoError(t, err)
+	assert.Equal(t, 98, pv4Limit)
 }
 
 func TestAllocIPAddress(t *testing.T) {