kuberneteskubernetes-ingressaws-albexternal-dns

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


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

Solution

  • 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.