CNI - resolving *.cluster.local

[PawelJi]

Description

Node could not resolve local dns addresses. How to fix configuration(maybe resolve.conf ?) to use core-dns?

I have configured pod:

apiVersion: v1
kind: Pod
metadata:
  name: dns-test
spec:
  containers:
  - name: dns-test
    image: busybox
    command: ["sleep", "3600"]

On node:

nslookup kubernetes.default.svc.cluster.local
Server:		185.12.64.1
Address:	185.12.64.1#53

** server can't find  kubernetes.default.svc.cluster.local: NXDOMAIN

In consequence, it could not use internal network to connect to other pods and services.

Kube.tf file

module "kube-hetzner" {
  providers = {
    hcloud = hcloud
  }
  hcloud_token = var.hcloud_token != "" ? var.hcloud_token : local.hcloud_token
  source = "kube-hetzner/kube-hetzner/hcloud"
  network_region = "eu-central" 
  control_plane_nodepools = [
    {
      name        = "control-plane-fsn1",
      server_type = "cx22",
      location    = "fsn1",
      labels      = [],
      taints      = [],
      count       = 1
    },
    {
      name        = "control-plane-nbg1",
      server_type = "cx22",
      location    = "nbg1",
      labels      = [],
      taints      = [],
      count       = 1
    },
    {
      name        = "control-plane-hel1",
      server_type = "cx22",
      location    = "hel1",
      labels      = [],
      taints      = [],
      count       = 1
    }
  ]
  agent_nodepools = [
    {
      name        = "agent-small",
      server_type = "cx22",
      location    = "fsn1",
      labels      = [],
      taints      = [],
      count       = 1
    },
    {
      name        = "agent-large",
      server_type = "cx32",
      location    = "nbg1",
      labels      = [],
      taints      = [],
      count       = 1
    },
    {
      name        = "storage",
      server_type = "cx32",
      location    = "fsn1",
      labels      = [
        "node.kubernetes.io/server-usage=storage"
      ],
      taints      = [],
      count       = 1
      longhorn_volume_size = 60
    },
    {
      name        = "egress",
      server_type = "cx22",
      location    = "fsn1",
      labels = [
        "node.kubernetes.io/role=egress"
      ],
      taints = [
        "node.kubernetes.io/role=egress:NoSchedule"
      ],
      floating_ip = true
      count = 1
    },
    {
      name        = "agent-arm-small",
      server_type = "cax11",
      location    = "fsn1",
      labels      = [],
      taints      = [],
      count       = 1
    },
    {
      name        = "agent-arm-small-second",
      server_type = "cax11",
      location    = "fsn1",
      labels      = [],
      taints      = [],
      nodes = {
        "1" : {
          location                  = "nbg1"
          labels = [
            "testing-labels=a1",
          ]
        },
        "20" : {
          labels = [
            "testing-labels=b1",
          ]
        }
      }
    },
  ]
  load_balancer_type     = "lb11"
  load_balancer_location = "fsn1"
  enable_longhorn = true
  longhorn_namespace = "longhorn-system"
  system_upgrade_use_drain = true
  extra_firewall_rules = [
     {
       description = "To Allow ArgoCD access to resources via SSH"
       direction       = "out"
       protocol        = "tcp"
       port            = "22"
       source_ips      = [] 
       destination_ips = ["0.0.0.0/0", "::/0"]
     }
   ]
  cni_plugin = "cilium"
  dns_servers = [
     "185.12.64.1",
     "2a01:4ff:ff00::add:1",
  ]
}
provider "hcloud" {
  token = var.hcloud_token != "" ? var.hcloud_token : local.hcloud_token
}
terraform {
  required_version = ">= 1.5.0"
  required_providers {
    hcloud = {
      source  = "hetznercloud/hcloud"
      version = ">= 1.43.0"
    }
  }
}
output "kubeconfig" {
  value     = module.kube-hetzner.kubeconfig
  sensitive = true
}
variable "hcloud_token" {
  sensitive = true
  default   = ""
}

Screenshots

No response

Platform

Mac

[mysticaltech]

@PawelJi It's the first time I hear of such a use case. Usually what is done is that you port-forward to get access to pods from your localhost. Maybe I misunderstood what you need, if it's the case let me know. Also check with chatgpt or claude.ai.

I do not believe something can be done here, so moving this to a conversation.

[PawelJi]

Yeah, just looking for opportunity to resolve some resource address like private image repository using cluster dns. Currently it is not possible, so have to use clusterIP, and is not best solution.