kubernetes/minikube

Add cluster DNS to node resolv.conf (cannot pull image from cluster-internal host name)

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#2,162 opened on Nov 6, 2017

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area/dnshelp wantedkind/featurelifecycle/frozenpriority/backlog

Description

Minikube version (use minikube version): v0.23.0

  • OS (e.g. from /etc/os-release): Linux xps 4.9.58 #1-NixOS SMP Sat Oct 21 15:21:39 UTC 2017 x86_64 GNU/Linux
  • VM Driver (e.g. cat ~/.minikube/machines/minikube/config.json | grep DriverName): virtualbox
  • ISO version (e.g. cat ~/.minikube/machines/minikube/config.json | grep -i ISO or minikube ssh cat /etc/VERSION): minikube-v0.23.6.iso

What happened:

Failed to pull image "docker-registry-luminous-parrot:4000/todo-list@sha256:c3fb64353659cad2e6e96af7b6d5e3e58340af74108a3e2b663f6df77debd872": rpc error: code = Unknown desc = Error response from daemon: Get https://docker-registry-luminous-parrot:4000/v2/: dial tcp: lookup docker-registry-luminous-parrot on 10.0.2.3:53: no such host

even though this service is available:

screenshot_2017-11-06_14-23-05

when I ssh into a pod in the same namespace:

# nslookup docker-registry-luminous-parrotServer:		10.0.0.10
Address:	10.0.0.10#53

Name:	docker-registry-luminous-parrot.default.svc.cluster.local
Address: 10.0.0.178

when I read /etc/resolv.conf from minikube:

$ minikube ssh
$ cat /etc/resolv.conf
nameserver 10.0.2.3

It looks like minikube has the wrong dns server. 10.0.0.10 finds the service correctly.

What you expected to happen:

I expect kubernetes to be able to pull the image based on that registry host name.

How to reproduce it (as minimally and precisely as possible):

minikube start --insecure-registry 10.0.0.0/24 --disk-size 60g
helm init
helm install incubator/docker-registry
# push an image to the registry
# try to create a deployment with the image using the registry

Contributor guide

Tech stack
godocker
Domain
devopsinfrastructure
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Kubernetes DNS basicsMinikube networkingresolv.conf configurationDocker image pulling
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate how Minikube configures the node's resolv.conf and whether it should include the cluster DNS server (e.g., kube dns IP) for resolving cluster internal hostnames from the node. Check comments in the issue for proposed fixes and examine Minikube's code related to DNS settings in the host machine, such as files in the 'pkg/minikube' directory or configuration for kubeadm. Coordinate with maintainers to decide if the resolution should be via kube dns or a different approach.
Add cluster DNS to node resolv.conf (cannot pull image from cluster-internal host name) · kubernetes/minikube#2162 | Good First Issue