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Retrieve VPC ID from EC2 instance the controller is running on if possible #2824

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merged 1 commit into from
Oct 22, 2022
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Retrieve VPC ID from EC2 instance the controller is running on if possible #2824

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58 changes: 50 additions & 8 deletions pkg/aws/cloud.go
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Original file line number Diff line number Diff line change
@@ -1,15 +1,18 @@
package aws

import (
"fmt"
"net"
"os"
"strings"

"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/endpoints"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/ec2"
"github.com/pkg/errors"
"github.com/prometheus/client_golang/prometheus"
amerrors "k8s.io/apimachinery/pkg/util/errors"
epresolver "sigs.k8s.io/aws-load-balancer-controller/pkg/aws/endpoints"
"sigs.k8s.io/aws-load-balancer-controller/pkg/aws/metrics"
"sigs.k8s.io/aws-load-balancer-controller/pkg/aws/services"
Expand Down Expand Up @@ -70,13 +73,6 @@ func NewCloud(cfg CloudConfig, metricsRegisterer prometheus.Registerer) (Cloud,

metadataSess := session.Must(session.NewSessionWithOptions(opts))
metadata := services.NewEC2Metadata(metadataSess)
if len(cfg.VpcID) == 0 {
vpcId, err := metadata.VpcID()
if err != nil {
return nil, errors.Wrap(err, "failed to introspect vpcID from EC2Metadata, specify --aws-vpc-id instead if EC2Metadata is unavailable")
}
cfg.VpcID = vpcId
}

if len(cfg.Region) == 0 {
region := os.Getenv("AWS_DEFAULT_REGION")
Expand Down Expand Up @@ -114,9 +110,19 @@ func NewCloud(cfg CloudConfig, metricsRegisterer prometheus.Registerer) (Cloud,
metricsCollector.InjectHandlers(&sess.Handlers)
}

ec2Service := services.NewEC2(sess)

if len(cfg.VpcID) == 0 {
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nit: i think we should use same check here, either len(cfg.VpcID) ==0 or vpcID == ""

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You were referring to this one and the one two lines below? The latter was replaced by an err check now that the infer function returns errors.

vpcID, err := inferVPCID(metadata, ec2Service)
if err != nil {
return nil, errors.Wrap(err, "failed to introspect vpcID from EC2Metadata or Node name, specify --aws-vpc-id instead if EC2Metadata is unavailable")
}
cfg.VpcID = vpcID
}

return &defaultCloud{
cfg: cfg,
ec2: services.NewEC2(sess),
ec2: ec2Service,
elbv2: services.NewELBV2(sess),
acm: services.NewACM(sess),
wafv2: services.NewWAFv2(sess),
Expand All @@ -126,6 +132,42 @@ func NewCloud(cfg CloudConfig, metricsRegisterer prometheus.Registerer) (Cloud,
}, nil
}

func inferVPCID(metadata services.EC2Metadata, ec2Service services.EC2) (string, error) {
var errList []error
vpcId, err := metadata.VpcID()
if err == nil {
return vpcId, nil
} else {
errList = append(errList, errors.Wrap(err, "failed to fetch VPC ID from instance metadata"))
}

nodeName := os.Getenv("NODENAME")
if strings.HasPrefix(nodeName, "i-") {
output, err := ec2Service.DescribeInstances(&ec2.DescribeInstancesInput{
InstanceIds: []*string{&nodeName},
})
if err != nil {
errList = append(errList, errors.Wrapf(err, "failed to describe instance %q", nodeName))
return "", amerrors.NewAggregate(errList)
}
if len(output.Reservations) != 1 {
errList = append(errList, fmt.Errorf("found more than one reservation for instance %q", nodeName))
return "", amerrors.NewAggregate(errList)
}
if len(output.Reservations[0].Instances) != 1 {
errList = append(errList, fmt.Errorf("found more than one instance with instance ID %q", nodeName))
return "", amerrors.NewAggregate(errList)
}

vpcID := output.Reservations[0].Instances[0].VpcId
if vpcID != nil {
return *vpcID, nil
}

}
return "", amerrors.NewAggregate(errList)
}

var _ Cloud = &defaultCloud{}

type defaultCloud struct {
Expand Down