K
Q

"services is forbidden: User \"system:serviceaccount:tick:external-dns\" cannot list resource \"services\" in API group \"\" at the cluster scope"

2/20/2020

I've been following the walkthrough to create an AWS ALB Ingress Controller for my app which is also deployed at an EKS cluster.
Everything seems okay , similar answers with the walkthrough but when it comes to the setting up of an external DNS I get the error :

kubectl logs -f $(kubectl get po | egrep -o 'external-dns[A-Za-z0-9-]+')

time="2020-02-20T16:21:57Z" level=error msg="services is forbidden: User \"system:serviceaccount:tick:external-dns\" cannot list resource \"services\" in API group \"\" at the cluster scope" time="2020-02-20T16:22:58Z" level=error msg="services is forbidden: User \"system:serviceaccount:tick:external-dns\" cannot list resource \"services\" in API group \"\" at the cluster scope"

every one minute . I made sure that all the permissions are the needed ones so it should not be because of that.

I tried the solutions from here , but nothing helped and I couldn't find any other solutions.

What does this error practically means? What should I do to fix it?

UPDATE EDIT my external-dns configuration looks like:

apiVersion: v1
kind: ServiceAccount
metadata:
  name: external-dns
  annotations:
    eks.amazonaws.com/role-arn: arn:aws:iam::*my*account*id*:role/EKSRole
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
  name: external-dns
rules:
- apiGroups: [""]
  resources: ["services"]
  verbs: ["get","watch","list"]
- apiGroups: [""]
  resources: ["pods"]
  verbs: ["get","watch","list"]
- apiGroups: ["extensions"]
  resources: ["ingresses"]
  verbs: ["get","watch","list"]
- apiGroups: [""]
  resources: ["nodes"]
  verbs: ["list","watch"]
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: external-dns-viewer
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: external-dns
subjects:
- kind: ServiceAccount
  name: external-dns
  namespace: tick
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: external-dns
spec:
  selector:
    matchLabels:
      app: external-dns
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: external-dns
      annotations:
        iam.amazonaws.com/role: arn:aws:iam::*my*account*id*:role/EKSRole
    spec:
      serviceAccountName: external-dns
      containers:
      - name: external-dns
        image: registry.opensource.zalan.do/teapot/external-dns:v0.5.9
        args:
        - --source=service
        - --source=ingress
        - --domain-filter=external-dns-test.my-org.com   #external-dns-test.my-org.com # will make ExternalDNS see only the hosted zones matching provided domain, omit to process all available hosted zones
        - --provider=aws
        - --policy=upsert-only # would prevent ExternalDNS from deleting any records, omit to enable full synchronization
        - --aws-zone-type=public # only look at public hosted zones (valid values are public, private or no value for both)
        - --registry=txt
        - --txt-owner-id=my-identifier
      securityContext:
        fsGroup: 65534
-- Flora Biletsiou
aws-alb
external-dns
kubernetes
kubernetes-ingress

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2 Answers

2/20/2020

I think you are using Amazon EKS with IAM Roles for Service Accounts therefore following this should work. The walkthrough you were following, in the external DNS section Step 2 yaml file doesn't have your

annotations:
    # Substitute your account ID and IAM service role name below.
    eks.amazonaws.com/role-arn: arn:aws:iam::ACCOUNT-ID:role/IAM-SERVICE-ROLE-NAME

This error practically means your serviceaccount (external-dns) doesn't have permissions to access the kubernetes api server

-- garlicFrancium
Source: StackOverflow
2/21/2020

Your error suggests that service account with name external-dns in tick namespace can't perform certain actions. In this case it is list services. To solve this you can apply the following:

apiVersion: v1
kind: ServiceAccount
metadata:
  name: external-dns
  namespace: tick
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
  name: external-dns-role
rules:
- apiGroups: [""]
  resources: ["services"]
  verbs: ["get","watch","list"]
- apiGroups: [""]
  resources: ["pods"]
  verbs: ["get","watch","list"]
- apiGroups: ["extensions"]
  resources: ["ingresses"]
  verbs: ["get","watch","list"]
- apiGroups: [""]
  resources: ["nodes"]
  verbs: ["list","watch"]
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: external-dns-role-binding
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: external-dns-role
subjects:
- kind: ServiceAccount
  name: external-dns
  namespace: tick

Note, that first rule inside ClusterRole is granting correct permissions to list services in "" apiGroup, which is solving the error you have reported in your question.

-- marcincuber
Source: StackOverflow