aws eks ALB, NLB error: service Failed build model due to unable to resolve at least one subnet

EKS AWS LBC is not able to auto-discover subnets

 

 

https://kubernetes-sigs.github.io/aws-load-balancer-controller/v2.5/deploy/subnet_discovery/

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Public subnets¶
Public subnets are used for internet-facing load balancers. These subnets must have the following tags:

Key	Value
kubernetes.io/role/elb	1 or ``

 

Private subnets¶
Private subnets are used for internal load balancers. These subnets must have the following tags:

Key	Value
kubernetes.io/role/internal-elb	1 or ``

 

Common tag¶
In version v2.1.1 and older of the LBC, both the public and private subnets must be tagged with the cluster name as follows:

Key	Value
kubernetes.io/cluster/${cluster-name}	owned or shared

 

But the subnet tags are already well set up.

and i finally find below answer.

 

https://stackoverflow.com/questions/66039501/eks-alb-is-not-to-able-to-auto-discover-subnets

 

kubectl get deployment -n kube-system aws-load-balancer-controller -oyaml |grep "cluster-name"

...

when install aws loadbalancer controller with helm, didn't update current eks-cluster-name

 

kubectl edit deployment -n kube-system aws-load-balancer-controller

or

helm upgrade ~

 

 

Events:
  Type     Reason                  Age                  From     Message
  ----     ------                  ----                 ----     -------
  Warning  FailedBuildModel        9m15s (x2 over 14m)  service  Failed build model due to unable to resolve at least one subnet
  Normal   SuccessfullyReconciled  7m3s                 service  Successfully reconciled

 

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other issue

https://keyhyuk-kim.medium.com/aws-eks%EC%97%90%EC%84%9C-subnet-cidr%EC%9D%84-%EC%9E%91%EA%B2%8C-%EC%9E%A1%EC%9C%BC%EB%A9%B4-%EC%83%9D%EA%B8%B0%EB%8A%94-%EB%B2%84%EA%B7%B8-unable-to-discover-at-least-one-subnet-5ef6aef361af

AWS ALB, subnet CIDR 범위로 인한 문제(unable to discover at least one subnet)

 

subnet cidr is too small

 

1. Confirm that you have at least two subnets in two different Availability Zones, which is a requirement for creating an Application Load Balancer.Note: You can create a Network Load Balancer with a single subnet.

2. For each subnet, specify a CIDR block with at least a /27 bitmask (for example: 10.0.0.0/27) and at least eight free IP addresses.

3. Confirm that the tags on the subnets are formatted correctly. For example, the tags must not have any leading or trailing spaces.