Minikube Ingress DNS

Build Status

DNS service for ingress controllers running on your minikube server

Overview

Problem

When running minikube locally you are highly likely to want to run your services on an ingress controller so that you don’t have to use minikube tunnel or NodePorts to access your services. While NodePort might be ok in a lot of circumstances in order to test some features an ingress is necessary. Ingress controllers are great because you can define your entire architecture in something like a helm chart and all your services will be available. There is only 1 problem. That is that your ingress controller works basically off of dns and while running minikube that means that your local dns names like myservice.test will have to resolve to $(minikube ip) not really a big deal except the only real way to do this is to add an entry for every service in your /etc/hosts file. This gets messy for obvious reasons. If you have a lot of services running that each have their own dns entry then you have to set those up manually. Even if you automate it you then need to rely on the host operating system storing configurations instead of storing them in your cluster. To make it worse it has to be constantly maintained and updated as services are added, remove, and renamed. I call it the /ets/hosts pollution problem.

Solution

What if you could just access your local services magically without having to edit your /etc/hosts file? Well now you can. This addon acts as a DNS service that runs inside your kubernetes cluster. All you have to do is install the service and add the $(minikube ip) as a DNS server on your host machine. Each time the dns service is queried an API call is made to the kubernetes master service for a list of all the ingresses. If a match is found for the name a response is given with an IP address as the $(minikube ip). So for example lets say my minikube ip address is 192.168.99.106 and I have an ingress controller with the name of myservice.test then I would get a result like so:

#bash:~$ nslookup myservice.test $(minikube ip)
Server:		192.168.99.169
Address:	192.168.99.169#53

Non-authoritative answer:
Name:	myservice.test $(minikube ip)
Address: 192.168.99.169

Installation

Start minikube

minikube start

Install the kubernetes resources

minikube addons enable ingress-dns

Add the minikube ip as a dns server

Mac OS

Create a file in /etc/resolver/minikube-profilename-test

domain test
nameserver 192.168.99.169
search_order 1
timeout 5

Replace 192.168.99.169 with your minikube ip and profilename is the name of the minikube profile for the corresponding ip address

If you have multiple minikube ips you must configure multiple files

See https://www.unix.com/man-page/opendarwin/5/resolver/ Note that even though the port feature is documented. It does not actually work.

Linux

Update the file /etc/resolvconf/resolv.conf.d/base to have the following contents

search test
nameserver 192.168.99.169
timeout 5

Replace 192.168.99.169 with your minikube ip

If your linux OS uses systemctl run the following commands

sudo resolvconf -u
systemctl disable --now resolvconf.service 

If your linux does not use systemctl run the following commands

TODO add supporting docs for Linux OS that do not use systemctl

See https://linux.die.net/man/5/resolver

Windows

TODO

Testing

Add the test ingress

kubectl apply -f https://github.com/kubernetes/minikube/blob/master/deploy/addons/ingress-dns/example/example.yaml

Note: Minimum Kubernetes version for example ingress is 1.14.7

Validate DNS queries are returning A records

nslookup hello-john.test $(minikube ip)
nslookup hello-jane.test $(minikube ip)

Validate domain names are resolving on host OS

ping hello-john.test

Expected results:

PING hello-john.test (192.168.99.169): 56 data bytes
64 bytes from 192.168.99.169: icmp_seq=0 ttl=64 time=0.361 ms
ping hello-jane.test
PING hello-jane.test (192.168.99.169): 56 data bytes
64 bytes from 192.168.99.169: icmp_seq=0 ttl=64 time=0.262 ms

Curl the example server

curl http://hello-john.test

Expected result:

Hello, world!
Version: 1.0.0
Hostname: hello-world-app-557ff7dbd8-64mtv
curl http://hello-jane.test

Expected result:

Hello, world!
Version: 1.0.0
Hostname: hello-world-app-557ff7dbd8-64mtv

Known issues

.localhost domains will not resolve on chromium

.localhost domains will not correctly resolve on chromium since it is used as a loopback address. Instead use .test, .example, or .invalid

.local is a reserved TLD

Do not use .local as this is a reserved TLD for mDNS and bind9 DNS servers

Mac OS

mDNS reloading

Each time a file is created or a change is made to a file in /etc/resolver you may need to run the following to reload Mac OS mDNS resolver.

sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist
sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist

TODO

  • Add a service that runs on the host OS which will update the files in /etc/resolver automatically
  • Start this service when running minikube addons enable ingress-dns and stop the service when running minikube addons disable ingress-dns

Contributors

Images used in this plugin

Image Source Owner
nginx-ingress ingress-nginx Nginx
minikube-ingress-dns minikube-ingress-dns Cryptex Labs