If you have ever worked with kubernetes, you'd know that minikube out of the box does not give you what you need for a quick setup. I'm sure you can go minikube start, everything's up... Great...kubectl get pods -n kube-system. It works, let's move on...

But what if it's not let's move on to something else. We need to look at this as a local test environment in capabilities. We can learn so much from it before applying to the lab. But, as always, there are a few tweaks we need to perform to give it the magic it needs to be a real environment.

Prerequisites

If you are looking into kubernetes, I would suppose that you know your linux's ABCs and you can install and configure minikube and its prerequisites prior to the beginning of this tutorial.

You can find the guide to install minikube and configure it on the minikube webpage.

Anyway, make sure you have minikube installed, kubectl and whatever driver dependencies you need to run it under that driver. In my case, I am using kvm2 which will be reflected in the commands given to start minikube.

Starting minikube

Let's start minikube.

$ minikube start --vm-driver=kvm2
Starting local Kubernetes v1.13.2 cluster...
Starting VM...
Getting VM IP address...
Moving files into cluster...
Setting up certs...
Connecting to cluster...
Setting up kubeconfig...
Stopping extra container runtimes...
Starting cluster components...
Verifying apiserver health ...
Kubectl is now configured to use the cluster.
Loading cached images from config file.


Everything looks great. Please enjoy minikube!

Great... At this point we have a cluster that's running, let's verify.

#  Id   Name       State    
--------------------------
 3    minikube   running

For me, I can check virsh. If you used VirtualBox you can check that.

We can also test with kubectl.

$ kubectl version
Client Version: version.Info{Major:"1", Minor:"13", GitVersion:"v1.13.3", GitCommit:"721bfa751924da8d1680787490c54b9179b1fed0", GitTreeState:"clean", BuildDate:"2019-02-01T20:08:12Z", GoVersion:"go1.11.5", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"13", GitVersion:"v1.13.2", GitCommit:"cff46ab41ff0bb44d8584413b598ad8360ec1def", GitTreeState:"clean", BuildDate:"2019-01-10T23:28:14Z", GoVersion:"go1.11.4", Compiler:"gc", Platform:"linux/amd64"}

Now what ? Well, now we deploy a few addons that we need to deploy in production as well for a functioning kubernetes cluster.

Let's check the list of add-ons available out of the box.

$ minikube addons list
- addon-manager: enabled
- dashboard: enabled
- default-storageclass: enabled
- efk: disabled
- freshpod: disabled
- gvisor: disabled
- heapster: enabled
- ingress: enabled
- kube-dns: disabled
- metrics-server: enabled
- nvidia-driver-installer: disabled
- nvidia-gpu-device-plugin: disabled
- registry: disabled
- registry-creds: disabled
- storage-provisioner: enabled
- storage-provisioner-gluster: disabled

Make sure you have dashboard, heapster, ingressand metrics-serverenabled. You can enable add-ons with kubectl addons enable .

What's the problem then ?

Here's the problem that comes next. How do you access the dashboard or anything running in the cluster ? Everyone online suggests you proxy a port and you access the dashboard. Is that really how it should work ? Is that how production system do it ?

The answer is of course not. They use different types of ingresses at their disposal. In this case, minikube was kind enough to provide one for us, the default kubernetes ingress controller, It's a great option for an ingress controller that's solid enough for production use. Fine, a lot of babble. Yes sure but this babble is important. So how do we access stuff on a cluster ?

To answer that question we need to understand a few things. Yes, you can use a NodePort on your service and access it that way. But do you really want to manage these ports ? What's in use and what's not ? Besides, wouldn't it be better if you can use one port for all of the services ? How you may ask ?

We've been doing it for years, and by we I mean ops and devops people. You have to understand that the kubernetes ingress controller is simply an nginx after the covers. We've always been able to configure nginx to listen for a specific hostname and redirect it where we want to. It shouldn't be that hard to do right ?

Well this is what an ingress controller does. It uses the default ports to route traffic from the outside according to hostname called. Let's look at our cluster and see what we need.

$ kubectl get services --all-namespaces
NAMESPACE     NAME                   TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)             AGE
default       kubernetes             ClusterIP   10.96.0.1                443/TCP             17m
kube-system   default-http-backend   NodePort    10.96.77.15              80:30001/TCP        17m
kube-system   heapster               ClusterIP   10.100.193.109           80/TCP              17m
kube-system   kube-dns               ClusterIP   10.96.0.10               53/UDP,53/TCP       17m
kube-system   kubernetes-dashboard   ClusterIP   10.106.156.91            80/TCP              17m
kube-system   metrics-server         ClusterIP   10.103.137.86            443/TCP             17m
kube-system   monitoring-grafana     NodePort    10.109.127.87            80:30002/TCP        17m
kube-system   monitoring-influxdb    ClusterIP   10.106.174.177           8083/TCP,8086/TCP   17m

In my case, you can see that I have a few things that arein NodePort configuration and you can access them on those ports. But the kubernetes-dashboard is a ClusterIP and we can't get to it. So let's change that by adding an ingress to the service.

Ingress

An ingress is an object of kind ingress that configures the ingress controller of your choice.

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: kubernetes-dashboard
  namespace: kube-system
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
  - host: dashboard.kube.local
    http:
      paths:
      - path: /
        backend:
          serviceName: kubernetes-dashboard
          servicePort: 80

Save that to a file kube-dashboard-ingress.yaml or something then run.

$ kubectl apply -f kube-bashboard-ingress.yaml
ingress.extensions/kubernetes-dashboard created

And now we get this.

$ kubectl get ingress --all-namespaces
NAMESPACE     NAME                   HOSTS                  ADDRESS   PORTS   AGE
kube-system   kubernetes-dashboard   dashboard.kube.local             80      17s

Now all we need to know is the IP of our kubernetes cluster of 1. Don't worry minikube makes it easy for us.

$ minikube ip
192.168.39.79

Now let's add that host to our /etc/hosts file.

192.168.39.79   dashboard.kube.local

Now if you go to http://dashboard.kube.local in your browser, you will be welcomed with the dashboard. How is that so ? Well as I explained, point it to the nodes of the cluster with the proper hostname and it works.

You can deploy multiple services that can be accessed this way, you can also integrate this with a service mesh or a service discovery which could find the up and running nodes that can redirect you to point to at all times. But this is the clean way to expose services outside the cluster.


Like it on Facebook, +1 on Google, Tweet it or share this article on other bookmarking websites.