Kubernetes – with Minikube and Helm – part 2

This is the second half of the Kubernetes with Minikube and Helm presentation, the first half explains all of the steps we went through to get to this point, and is available here:

In this section we cover the following:

  • Helm and Tiller – what they are, when & why you’d maybe use them
  • Helm and Tiller – prep, install and Helm Charts
  • Deploying Jenkins via Helm Charts
  • and WordPress w/MariaDB too
  • Wrap up

The below are mostly my technical notes from this session, with some added blurb/explanation.

Helm and Tiller – what they are, when & why you’d maybe use them

From the Helm site:

“Helm helps you manage Kubernetes applications — Helm Charts help you define, install, and upgrade even the most complex Kubernetes application. Charts are easy to create, version, share, and publish — so start using Helm and stop the copy-and-paste.”

https://helm.sh/

Helm is basically a package manager for Kubernetes applications. You can choose from a large list of Stable (or not so!) ready made packages and use the Helm Charts to quickly and easily deploy them to your own Kubernetes Cluster.

This makes light work of some very complex deployment tasks, and it’s also possible to extend these ready-made charts to suit your needs, and to write your own Charts from scratch, or pass your own values to override default ones, or… many other interesting options!

For this session we are looking at installing Helm, reviewing some example Helm Charts and deploying a few “vanilla” ones to the cluster we created in the first half of the session. We also touch upon the life-cycle of Helm Charts – it’s similar to dockers – and point out some of the ways this could be extended and customised to suit your needs – more on this at a later date hopefully.

Helm and Tiller – prep, install and Helm Charts

First, installing Helm – it’s as easy as this, run on your laptop/host that’s running the Minikube k8s we setup earlier:

Get & chmod the get_helm script, then run it:

curl https://raw.githubusercontent.com/kubernetes/helm/master/scripts/get > get_helm.sh

chmod 700 get_helm.sh

./get_helm.sh

Tiller is the client part of Helm and is deployed inside your k8s cluster. It’s set to be removed with the release of Helm 3, but the basic functionality wont really change. More details here https://helm.sh/blog/helm-3-preview-pt1/

Next we do the Tiller prep & install – add RBAC for tiller, deploy via helm and take a look at the running pods:

kubectl create serviceaccount -n kube-system tiller

kubectl create clusterrolebinding tiller-cluster-rule --clusterrole=cluster-admin --serviceaccount=kube-system:tiller

helm init --service-account tiller

kubectl --namespace kube-system get pods

Helm Charts – look at the list of available stable Charts, then deploy a couple. The github repo is here

https://github.com/helm/charts

Update the local helm repo info:

helm repo update

then, for example, install Redis from its Helm Chart to the k8s cluster as easily as this:

helm install stable/redis

or helm install stable/mysql and check the console output that explains how to access the newly deployed app.

keep an eye on the pods to see what’s going on: watch kubectl get pods -o wide

Deploying Jenkins via Helm Charts

helm ls

helm delete <things you don't want any more to free up resources>

helm install --set serviceType=NodePort --name jenki stable/jenkins

again, watch kubectl get pods -o wide

now get the URL for the Jenkins service from Minikube:

minikube service --url=true jenki-jenkins

Hit that URL in your browser, and grab the password in UI from Pods > Jenki and log in to Jenkins with the user “admin”:

That’s a Jenkins instance deployed via Helm and Tiller and a Helm Chart to our Kubernetes Cluster running inside Minikube via a VirtualBox VM… all done in a few minutes. And it’s all customisable, repeatable, highly scaleable and awesome.

and WordPress w/MariaDB too

This was the “bonus demo” if my laptop wasn’t on fire – and thanks to some rapid cleaning up it managed fine – showing how quickly we could deploy a functional WordPress with MariaDB backend to our k8s cluster using the Helm Chart.

To prepare for this I did a helm ls to see all the things I had running. then helm delete --purge jenki, gave it a while to recover then had to do

kubectl delete pods <jenkinpod>

before starting the WordPress Chart deployment with

helm install --set serviceType=NodePort --name wp-k8s stable/wordpress

watch kubectl get pods -o wide for a while – note the chart is configured with the mariadb pod as a pre requisite of the wordpress instance:

Once it’s started we requested the service URL from Minikube again, making ingress nice and easy:

minikube service --url=true wp-k8s-wordpress

Hit that in the browser, using https and accepting the cert warning…

then logged in as `user` and qureied for the password in the k8s secret…

echo Password: $(kubectl get secret wp-k8s-wordpress -o
jsonpath="{.data.wordpress-password}" | base64 --decode)

and logged in to WordPress:

Wrap up

That’s it – we covered a lot in this session, and plan to use this as a platform to explore Helm in more detail later, writing our own Helm Charts and providing our own customisations to them.

minikube delete; rm -rf ~/.minikube

Cleans up everything we’d done:

Leaving just the local tools to remove if you want to – see the first half for a reminder.

Cheers,

Don

Kubernetes – with Minikube and Helm – part 1

Intro:

This is the first of two posts on Kubernetes and Helm Charts, focusing on setting up a local development environment for Kubernetes using Minikube, then exploring Helm for package management and quickly and easily deploying several applications to the cluster – NGINX, Jenkins, WordPress with a MariaDB backend, MySQL and Redis.

The content is taken from the practical/demo session I wrote and published in Github here:

https://github.com/AutomatedIT/presentations/blob/master/minikube_demo.md

for this Meetup session we ran in Edinburgh in June 2019:

“Kubernetes – getting started with Minikube, Helm and Tiller” https://www.meetup.com/Automated-IT-Solutions/events/261623765/

<ramble>

One of the key objectives and challenges here was getting a useful local Kubernetes environment up and running as quickly and easily as possible for as wide an audience as we could- there’s so much to the Kubernetes ecosystem that it’s very easy to get side-tracked, and we could have (happily) spent a long time discussing the myriad of alternative possible solutions.

We plan to go “deeper” on all of this in future sessions and have an in-depth Helm session in the works, but for this session we were focused on creating a practical starting point.

</ramble>

Don

What is covered here:

  • Minikube – what it is (& isn’t) & why you’d use it (or not)
  • Kubernetes and Minikube components and concepts
  • setup for Mac and Linux
  • creating a first Kubernetes cluster in Minikube
  • minikube addons – what they are and how they can help you
  • minikube docker env – using DOCKER_HOST with minikube VM
  • Kubernetes dashboard with Heapster and Metrics Server – made easy by Minikube
  • kubectl – some examples and alternatives
  • example app – “hello (Kubernetes) world” minikube style with NGINX, scaling your world

and the second post covers:

  • Helm and Tiller – what they are, when & why you’d maybe use them
  • Helm and Tiller – prep, install and Helm Charts
  • Deploying Jenkins via Helm Charts
  • and WordPress w/MariaDB too
  • wrap up

Minikube – what it is (& isn’t) & why you’d use it (or not)


What it is, why you’d use it etc.

Local development of k8s – runs a single node Kubernetes cluster in a Virtual Machine on your laptop/PC.

All about making things easy for local development, it is not a production solution, or even close to it.

There are many other ways to run k8s, they all have their pros and cons and use cases. The slides form the Meetup covered this on more detail and include links for further info – they are available here:

Kubernetes and Minikube components and concepts

The (above) slides also cover this section:
Kubernetes components and concepts
what it solves
how Minikube works


Setup for Mac and Linux

There are three things you need to set up for this, they are:
VirtualBox: https://www.virtualbox.org/wiki/Downloads
Minikube: https://kubernetes.io/docs/tasks/tools/install-minikube/
kubectl: https://kubernetes.io/docs/tasks/tools/install-kubectl/

Using Ubuntu for example:

curl -Lo minikube https://storage.googleapis.com/minikube/releases/v1.1.0/minikube-linux-amd64 && chmod +x minikube && sudo cp minikube /usr/local/bin/ && rm minikube

curl -LO https://storage.googleapis.com/kubernetes-release/release/v1.14.0/bin/linux/amd64/kubectl

`chmod +x ./kubectl

`sudo mv ./kubectl /usr/local/bin/kubectl`

Cleanup/prep – if required, remove any previous cluster & settings

`minikube delete; rm -rf ~/.minikube`

Creating a first Kubernetes cluster in Minikube

Here we create a first Kubernetes cluster with Minikube, then take a look around in & outside of the VM.

With the above initial setup done, it’s as simple as running this in a shell:

minikube start

Note you could optionally give this Cluster a name, if you are likely to have more than one for different branches of development for example. This is also where you could specify the VM provider if you want to use something other than VirtualBox – there are more details here:

https://kubernetes.io/docs/setup/learning-environment/minikube/#starting-a-cluster

This should produce output like the following, and it may well take a few minutes as the VM is downloaded and started, then a stack of Docker images are started up inside that….

At this point you should be able to see the minikube VM running in the VirtualBox GUI:

Now it’s running, we can connect from our local shell directly to the one inside the running VM by simply issuing:

minikube ssh

This will put you inside the VM where the Kubernetes Cluster is being run, and we can see and interact with the running components, for example:

docker images

should show all of the downloaded images:

and you could do this to see the running containers:

docker ps

Quitting out of the VM puts us back on the local host, where we can use kubectl to query the status of the Minikube cluster – the initial setup has told kubectl about the Minikube-managed Kubernetes Cluster, meaning there’s no other setup required here:

kubectl cluster-info

kubectl get nodes

kubectl describe nodes

minikube addons – what they are and how they can help you

Show some of the ways minkube makes things easier for local dev

First, take a moment to look around these two local folders:

ls -al ~/.minikube; ls -al ~/.kube

These are where Minikube keeps its settings and the VM Image, and where kubectl settings are persisted – and updated by Minikube.

With Minikube you’ve often got the option to either use kubectl directly, or to use some Minikube built-in features to make your life easier.

Addons are one of these features, allowing you to very easily add – or remove – functionality from the cluster like this:

minikube addons list

minikube addons enable heapster

minikube addons enable metrics-server

With those three lines we’ve taken a look at the available addons and their current status, and selected to enable both heapster and the metrics server. This was done to give us cpu and mem stats in the Kubernetes Dashboard, which we will set up in a moment. The output should look something like this:

minikube config view

shows the current state of the config – i.e. what changes have been made, so we can keep a track of them easily.

kubectl --namespace kube-system get pods

now we can enable the dashboard:

minikube addons enable dashboard

and check again to see the current state

minikube addons list

we’ll connect to the Dashboard and take a look around in a moment, but first…

minikube docker env – using the DOCKER_HOST in you minikube VM – how & why


Minikube docker-env – setup local docker client to use minikube docker host

We’re going to look at connecting our local docker client to the docker host inside the Minikube VM. This is made easy by:

minikube docker-env

if you run that command on its own it wiull show you what settings it will export and you can set them by doing:

eval ${minikube docker-env}

From then on, in that shell, your local docker commands will use the docker host inside Minikube.

This is very useful for debugging and local development – when you change and deploy anything to your Kubernetes Cluster, you can easily tail the logs or check for errors or issues. You can also do all of this via the dashboard or kubectl too if you prefer, but it’s another handy and powerful feature from Minikube.

The following image shows the result of running this command:

eval $(minikube docker-env) && docker ps | grep -i metrics

so we can now use our local docker client to run docker commands like…

docker ps

docker ps | grep -i metrics

docker logs -f <some container id>

etc.

Kubernetes dashboard with Heapster and Metrics Server – made easy by Minikube

Minikube k8s dashboard – here we will start up the k8s dashboard and take look around.

We’ve delayed starting the dashboard up until after we enabled the metrics-server & heapster components we deployed earlier. By doing it in this order, the dashboard will automatically detect and use these components, giving us cpu & mem stats and a nicer looking dash, with no additional config required.

Starting the dashboard simply involved running

minikube dashboard

and waiting for a minute…

That should fire up your browser automatically, then you can take a look around at things like Default namespace > Nodes

and in the namespace kube-system > Deployments

and kube-system > Pods

You can see the logs and statuses of everything running in your k8s cluster – from the core components we covered at the start, to the dashboard, metrics and heapster we enabled recently, and the application we’re going to deploy and scale up soon.

kubectl – some examples and alternatives

# kubectl command line – look at kubectl and keep an eye on things
kubectl get deployment -n kube-system

kubectl get pods -o wide -n kube-system

kubectl get services

kubectl

example app – “hello (Kubernetes) world” minikube style with NGINX, scaling your world

Now we’ll deploy the most basic application we can – a “Hello World” style NGINX docker image.

It’s as simple as this, where nginx is the name of the docker image you want to deploy, hello-nginx is the label you want to give it, and port 80 is where you want it to listen:

kubectl run hello-nginx --image=nginx --port=80

that shouldn’t take long, and you can watch the progress like this:

kubectl get pods -o wide

We can then expose the deployment using NodePort:

kubectl expose deployment hello-nginx --type=NodePort

then we can ask Minikube to provide the URL for Ingress:

minikube service --url=true hello-nginx

and hitting that URL in your browser should show the obvious:

“Welcome to nginx!

If you see this page, the nginx web server is successfully installed and working. Further configuration is required.”

you can keep an eye on the Service with

kubectl get svc

while we scale to x3 replicas:

kubectl scale --replicas=3 deployment/hello-nginx

and take a look at what happens with

kubectl get deployment

kubectl get pods -o wide

or check in the Dashboard to see something like this:

and monitor what’s going on in our “hello world” NGINX app with kubectl then scale it down to 0 or 1 or whatever you like…

kubectl get deployment

kubectl get pods -o wide

kubectl scale --replicas=0 deployment/hello-nginx

Next post – Helm & Tiller onwards…

Meetup – Kubernetes with Minikube and Helm Charts

We are presenting a Kubernetes-related Meetup on Wednesday 5th June in Edinburgh.

This time we explore setting up a local development environment for Kubernetes using Minikube and Helm Charts. We will deploy NGINX to the Cluster and scaled it up and down, then use Helm Charts to deploy Jenkins, WordPress and MariaDB.

if you’d like to join in please book a space via our Meetup (below) – it’s free, and the Peoples Postcode Lottery are kindly hosting the event and providing the beer and pizza too! Wednesday 5th June 2019 from 6:30 PM in the Peoples Postcode Lottery offices at 28 Charlotte Square in Edinburgh.

Kubernetes – getting started with Minikube, Helm and Tiller

Wednesday, Jun 5, 2019, 6:30 PM

Wemyss House
28 Charlotte Square Edinburgh, GB

38 Members Went

In collaboration with Hays and the People’s Postcode Lottery, Automated IT Solutions are running a Meetup on Kubernetes with Minikube, Helm and Tiller. The session starts off with an overview of the main Kubernetes concepts and components, then runs through building your own local Kubernetes Cluster with Minikube. After deploying and scaling our fi…

Check out this Meetup →


I have been planning this session for ages, and hope that it will become the basis for several future talks and ideas, including deploying Blockchain to a Kubernetes cluster, then adding a Ruby and Sinatra based application that will use it.

Jenkins Global Pipeline Libraries – a v.quick start guide

This post runs through the steps required to start using Global Pipeline Libraries in your Jenkins Pipelines.

There are many posts about these all over the ‘net, but they mostly seemed overly complex and not too helpful to me – I just wanted to know how to get the most basic example possible working quickly on my dev Jenkins instance, so I could see how they work in practice and take it from there.

That’s what this post covers – getting a simple “Hello World” type example library published and made available in Jenkins, then calling it very easily from within a Pipeline job with the expected results. More detail and advanced usage to come later… these are a very powerful addition to Jenkins pipelines.

This is done in three simple and logical steps:

Create a Library and Publish it

Tell Jenkins about this nice new library

Calling the Global Library from my Jenkins Pipeline


The first step is to…

Create your Library and publish it somewhere.

I have reused one of my existing GitHub repos: https://github.com/DonaldSimpson/groovy.git for this example, but most version control systems should do just as well.

That’s all that’s needed for this most-basic example – here is the code in plain text, as taken from the guide here:

#!/usr/bin/env groovy
def call(String name = 'human') {
    // Any valid steps can be called from this code, just like in other
    // Scripted Pipeline
    echo "Hello, ${name}."
}

It is important to note that the file is in a “vars” directory, this is the naming convention Jenkins expects to find your groovy libraries within, and is best followed.

A. Note

Next step is to:

Tell Jenkins about this nice new library

This is done by going to Manage Jenkins then Configure System, then scrolling down to Global Pipeline Libraries and defining a new instance of one, just like this:

The settings used here are:

Name: mycommonlibs // any name you’d like to reference these libraries by

Default version: master // or use a branch or version number if you prefer

I then checked the three tick boxes, especially the Load implicitly which removes the need to load Libraries explicitly in your Jenkinsfile (you can do this and it may be very useful depending on your needs, but I want simple and easy for now).

The final section tells Jenkins where this Library is:

https://github.com/DonaldSimpson/groovy.git

and I provide a user to access GitHub with.

That is all that is needed to set up a Library and tell Jenkins all about it.

Note that anyone with write access to the location of your defined Libraries will effectively have full access to your Jenkins instance

W. Arning

And finally, it’s time time for a test drive…

Calling the Global Library from my Jenkins Pipeline:

    sayHello ()
    sayHello 'Donald'

To end up with a mega-basic Pipeline that looks like this:

When this Jenkins Pipeline job is run, it generates the following output:

Summary

Which as you can see means that Jenkins has pulled in the Shared Library from GitHub, resolved and called the sayHello() method from the remote common library, called it again with a passed parameter (‘Donald’) and produced the expected results. Yay. How neat and how easy was that?

There’s a whole lot more you can do with Global Pipeline Libraries in Jenkins. From this point you can easily add complexity and functionality to build up a library of powerful and useful utilities that will greatly improve the quality and manageability of your Pipelines.

I plan to expand on some of these points in a later post, but hopefully this shows how to quickly and easily start using them.

Cheers,

Don

Kubernetes – Dashboard with Heapster stats

Previous related posts:

Introduction/background

It’s pretty easy to deploy a functional Kubernetes dashboard to a Kubernetes Cluster, either using the stable Helm Chart or the official Kubernetes Dashboard project directly.

What was a little trickier, was getting live stats for my cluster – cpu and mem load etc – to show up inside the dashboard, so that you can see the status of the various deployments and pods on your cluster at a glance from one central location.

This combination of tools also makes it easy to add on Grafana dashboards that display whatever cluster stats you want from InfluxDB or Prometheus via Heapster, producing something along these lines:

Image
Image

This post documents the steps I took to get things working the way I want them.

Adding Heapster to a Kubernetes Cluster

I’ve used Heapster before and found it did everything I wanted without any problem, especially with an InfluxDB backend, but it’s now being deprecated and replaced with the new metrics-server (and others), which at the time I was doing this doesn’t integrate with the kubernetes dashboard so wouldn’t give me the stats I was looking for., which are this kind of thing…

and this

Note that it’s slightly easier to get Heapster stats working first, then when you add on the dashboard it’ll pick them up.

Heapster can be installed using the default project here, but it will not work with the current/latest version of Kubernetes Dashboard like that, and some changes are needed to make the two play nicely together.

I followed the steps in this very helpful post: https://brookbach.com/2018/10/29/Heapster-on-Kubernetes-1.11.3.html

and created my own fork of the official Heapster repo with the recommended changes then made to it, so now I can then simply (re)apply those settings whenever I rebuild my Cluster, and things should keep working.

My GitHub repo for this is here:

https://github.com/DonaldSimpson/heapster

and after cloning it (with the needed changes already done in that repo) locally I applied those files as described in the above post:

$ kubectl create -f ./deploy/kube-config/rbac/

then

$ kubectl create -f ./deploy/kube-config/influxdb/

Note that it may take a while for things to start happening…

The simplest test to see when/if Heapster is working is to check with kubectl top against a node or pod like so:

ansible@umaster:~$ kubectl top node umaster
NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
umaster 144m 3% 3134Mi 19%

ansible@umaster:~$ kubectl top node ubuntu01
NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
ubuntu01 121m 6% 2268Mi 59%
ansible@umaster:~

If you get stats something like the above back things are looking good, but if you get a “no stats available” message, you’ve got some fundamental issues. Time to go check the logs and look for errors. I had quite a series of them until I made the above changes, including many access verboten errors like:

reflector.go:190] k8s.io/heapster/metrics/util/util.go:30: Failed to list *v1.Node: nodes is forbidden: User “system:serviceaccount:kube-system:heapster



Kubernetes Dashboard with user & permissions sorted

Next, I deployed the dashboard as simply as this:

https://github.com/kubernetes/dashboard
kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v1.10.1/src/deploy/recommended/kubernetes-dashboard.yaml

but will probably use the Helm Chart for the kubernetes-dashboard next, which I think uses the same project.

Once deployed, I needed to edit

kubectl -n kube-system edit service kubernetes-dashboard

as per here:
https://github.com/kubernetes/dashboard/wiki/Accessing-Dashboard—1.7.X-and-above
and change

 type: ClusterIP 

to

type: NodePort

And I also applied these changes to create a Cluster Role and Service Admin account:

ansible@umaster:~/ansible01$ cat <<EOF | kubectl create -f -
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
name: kubernetes-dashboard
labels:
k8s-app: kubernetes-dashboard
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: cluster-admin
subjects:
kind: ServiceAccount
name: kubernetes-dashboard
namespace: kube-system
EOF

I then restarted the dashboard pod to pick up the changes:

kubectl delete pod kubernetes-dashboard-57df4db6b-4tcmk --namespace kube-system

Now it should be time to test logging in to the Dashboard. If you don’t have a service endpoint created already/automatically, you can find and do a quick test via the current NodePort by running

kubectl -n kube-system get service kubernetes-dashboard

Then hit your cluster IP with that PORT in your browser and you should see a login page like:

Presenting the next hurdle… how to log in to your nice new Dashboard and see all the shiny new info and metrics!

Run
sudo kubectl -n kube-system get secret
and look/grep for something starting with “kubernetes-dashboard-token-” that we created above. Then do this to get the token to log in with full perms:


sudo kubectl -n kube-system describe secret kubernetes-dashboard-token-rlr9m

or whatever unique name you found above – hitting tab after the last “-” should work if you have completion set up.

That should give you a TOKEN you can copy and log in to the Dashboard with.

You should now have full access in the dashboard, no more permissions errors, and be able to see the stats provided by Heapster too.

My TODO list to finish off this part of the project properly includes:

  • exposing the dashboard as a service on a suitable free port
  • resetting the cluster
  • running through things again to ensure it all works first time
  • see if using the Helm chart provides any benefits
  • adding in monitoring and alerting via Grafana.

but before all that, I’m planning on having fun with some Kubernetes + Blockchain, Ethereum and Ruby/Sinatra projects I’ve got in the works!

Kubernetes – adding persistent storage to the Cluster

Previously

In the last Kubernetes post…

I wrote about getting Helm and Tiler working on the Kubernetes Cluster I set up here…

There was an obvious flaw in the example MySQL Chart I deployed via Helm and Tiller, in that the required Persistent Volume Claims could not be satisfied so the pod was stuck in a “Pending” state for ever.

Adding Persistent Storage

In this post I will sort that out, by adding Persistent Storage to the Cluster and redeploying and testing the same Chart deployed via “helm deploy stable/mysql“. This time, it should be able to claim all of the resources it needs with no tweaking or hints supplied…

First a few notes on some of the commands and tools I used for troubleshooting what was wrong with the mysql deploy.

watch -d 'sudo kubectl get pods --all-namespaces -o wide'

watch -d kubectl describe pod wise-mule-mysql

kubectl attach wise-mule-mysql-d69788f48-zq5gz -i

The above commands showed a pod that generally wasn’t happy or connectable, but little detail.

Running “kubectl get events -w” is much more informative:

LAST SEEN   TYPE      REASON              KIND                    MESSAGE
17m         Warning   FailedScheduling    Pod                     pod has unbound immediate PersistentVolumeClaims
17m         Normal    SuccessfulCreate    ReplicaSet              Created pod: quaffing-turkey-mysql-65969c88fd-znwl9
2m38s       Normal    FailedBinding       PersistentVolumeClaim   no persistent volumes available for this claim and no storage class is set
17m         Normal    ScalingReplicaSet   Deployment              Scaled up replica set quaffing-turkey-mysql-65969c88fd to 1

and doing “kubectl describe pod <pod name>” is also very useful:

<snip a whole load of events and details>
  Type     Reason            Age                    From               Message
  ----     ------            ----                   ----               -------
  Warning  FailedScheduling  5m26s (x2 over 5m26s)  default-scheduler  pod has unbound immediate PersistentVolumeClaims

Making it pretty clear what’s going on and exactly what is noticeably absent from the Cluster.

My initial plan had been to use GlusterFS and Heketi, but having dabbled with this before and knowing it wasn’t really something I wanted to do for this use case, it was a bit of Yak Shaving I’d really like to avoid if possible.

So, I had a look around and found “Rook“. This sounded much simpler and more suited to my needs. It’s also open source, Apache licensed, and works on multi-node clusters. I’d previously considered using hostPath storage but it’s a bit too basic even for here, and would restrict me to a single node cluster due to the (lack of) replication, missing a lot of the point of a Cluster, so I thought I’d give Rook a shot.

Here’s the guide on deploying Rook that I used:

https://github.com/hobby-kube/guide#deploying-rook

Which says to

Apply the storage manifests in the following order:

storage/00-namespace.yml

storage/operator.yml (wait for the rook-agent pods to be deployed kubectl -n rook get pods before continuing)

storage/cluster.yml

storage/storageclass.yml

storage/tools.yml

I tried to follow this but had some issues, which I will try and clarify when I run through this again – I’d made a bit of a mess trying a bit of Gluster and some hostPath and messing about with the default storage class etc, so it was quite possibly “just me”, and not Rook to blame here 🙂 This is some of my shell history:

kubectl apply -f https://raw.githubusercontent.com/rook/rook/release-0.5/cluster/examples/kubernetes/rook-operator.yaml
kubectl apply -f https://raw.githubusercontent.com/rook/rook/release-0.5/cluster/examples/kubernetes/rook-cluster.yaml
kubectl apply -f https://raw.githubusercontent.com/rook/rook/release-0.5/cluster/examples/kubernetes/rook-storageclass.yaml
kubectl -n rook get pods
kubectl apply -f https://github.com/hobby-kube/manifests/blob/master/storage/00-namespace.yml
kubectl apply -f https://github.com/hobby-kube/manifests/blob/master/storage/00-namespace.yml
kubectl apply -f https://github.com/hobby-kube/manifests/blob/master/storage/00-namespace.yml
kubectl apply -f https://raw.githubusercontent.com/rook/rook/release-0.5/cluster/examples/kubernetes/rook-operator.yaml
kubectl apply -f https://raw.githubusercontent.com/rook/rook/release-0.5/cluster/examples/kubernetes/rook-cluster.yaml
watch -d 'sudo kubectl get pods --all-namespaces -o wide'
kubectl apply -f https://raw.githubusercontent.com/rook/rook/release-0.5/cluster/examples/kubernetes/rook-storageclass.yaml

I definitely ran through this more than once, and I think it also took a while for things to start up and work – the subsequent runs went much better than the initial ones anyway. I also applied a few patches to the rook user and storage class (below) – these and many other alternatives were recommended by others facing similar sounding issues, but I think for me the fundamental is solved further below, re the rbd binary missing from $PATH, and installing ceph:


kubectl get secret rook-rook-user -oyaml | sed "/resourceVer/d;/uid/d;/self/d;/creat/d;/namespace/d" | kubectl -n kube-system apply -f -

kubectl get secret rook-rook-user -oyaml | sed "/resourceVer/d;/uid/d;/self/d;/creat/d;/namespace/d" | kubectl -n default -f -
 kubectl get secret rook-rook-user -oyaml | sed "/resourceVer/d;/uid/d;/self/d;/creat/d;/namespace/d" | kubectl -n default apply -f -
  kubectl patch storageclass rook-block -p '{"metadata":{"annotations": {"storageclass.kubernetes.io/is-default-class": "true"}}}

That all done, I still had issues with my pods, specifically this error:

MountVolume.WaitForAttach failed for volume “pvc-4895a379-104b-11e9-9d98-000c29702bc8” : fail to check rbd image status with: (executable file not found in $PATH), rbd output: ()

which took me a little while to figure out. I think reading this page on RBD gave me the hint that there was something (well yeah, the rbd binary specifically) missing on the hosts, but there’s a lot of talk of folk solving this by creating custom images with the rbd binary added to the $PATH in them, replacing core k8s containers with them, which didn’t sound too appealing to me. I had assumed that the images would include the binaries, but hadn’t checked this is any way.

This issue may well be part or possibly all of the reason why I ran the above commands repeatedly and applied all of those patches.

The simple yet not too obvious solution to this – in my case anyway – was to ensure that the ceph common package was available both on the master:

apt-get update && apt-get install ceph-common -y

and critically that it was also available on each of the worker nodes too.

Once that was done, I think I deleted and reapplied everything rook-related again, then things started working as they should, finally.

A quick check:

ansible@umaster:~$ kubectl get sc
NAME PROVISIONER AGE
rook-block (default) rook.io/block 22h

And things are looking much better now.

Checking the Dashboard I can see a Rook namespace with a number of Rook pods all looking green, and Persistent Volume Claims in the default namespace too:

Test with an example – “helm install stable/mysql”, take 2…

To verify this I re ran the same Helm Chart for mysql, with no changes or overrides, to ensure that rook provisioning was working, that it was properly detected and used as the default storage class in the Cluster with no args/hints needed.

The output from running “helm install stable/mysql” includes this info:


MySQL can be accessed via port 3306 on the following DNS name from within your cluster:
donmysql.default.svc.cluster.local

To get your root password run:

    MYSQL_ROOT_PASSWORD=$(kubectl get secret –namespace default donmysql -o jsonpath=”{.data.mysql-root-password}” | base64 –decode; echo)

To connect to your database:

1. Run an Ubuntu pod that you can use as a client:

    kubectl run -i –tty ubuntu –image=ubuntu:16.04 –restart=Never — bash -il

2. Install the mysql client:

    $ apt-get update && apt-get install mysql-client -y

3. Connect using the mysql cli, then provide your password:
    $ mysql -h donmysql -p

So I tried the above, opting to create an ubuntu client pod, installing mysql utils to that then connecting to the above MySQL instance with the root password like so:

ansible@umaster:~$  MYSQL_ROOT_PASSWORD=$(kubectl get secret --namespace default donmysql  -o jsonpath="{.data.mysql-root-password}" | base64 --decode; echo)
ansible@umaster:~$ echo $MYSQL_ROOT_PASSWORD
<THE ROOT PASSWORD WAS HERE>
ansible@umaster:~$ kubectl run -i --tty ubuntu --image=ubuntu:16.04 --restart=Never -- bash -il
If you don't see a command prompt, try pressing enter.
root@ubuntu:/#
root@ubuntu:/# apt-get update && apt-get install mysql-client -y
Get:1 http://archive.ubuntu.com/ubuntu xenial InRelease [247 kB]
Get:2 http://security.ubuntu.com/ubuntu xenial-security InRelease [107 kB]
<snip a load of boring apt stuff>
Setting up mysql-common (5.7.24-0ubuntu0.16.04.1) ...
update-alternatives: using /etc/mysql/my.cnf.fallback to provide /etc/mysql/my.cnf (my.cnf) in auto mode
Setting up mysql-client-5.7 (5.7.24-0ubuntu0.16.04.1) ...
Setting up mysql-client (5.7.24-0ubuntu0.16.04.1) ...
Processing triggers for libc-bin (2.23-0ubuntu10) ...
root@ubuntu:/# mysql -h donmysql -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 67
Server version: 5.7.14 MySQL Community Server (GPL)
<snip some more boring stuff>
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.00 sec)
mysql> exit
Bye
root@ubuntu:/

In the Kubernetes Dashboard (loads more on that little adventure coming soon!) I can also see that the MySQL Pod is Running and looks happy, no more Pending or Init issues for me now:

and that the Rook Persistent Volume Claims are present and looking healthy too:

Conclusion & next steps

That’s storage sorted, kind of – I’m not totally happy everything I did was needed, correct and repeatable yet, or that I know enough about this.

Rook.io looks very good and I’m happy it’s the best solution for my current needs, but I can see that I should have spent more time reading the documentation and thinking about prerequisites, yadda yadda. To be honest when it comes to storage I’m a bit of a Luddite – i just want it to be there and work as I’d expect it to, and I was keen to move on to the next steps….

I plan to scrub the k8s cluster shortly and run through this again from scratch to make sure I’ve got it clear enough to add to my provisioning pipeline process.

Next, a probably not-too-brief post on how I got Heapster stats working with an InfluxDB backend monitoring stats for both the Master and Nodes, installing a usable Kubernetes Dashboard, and getting that working with suitable access/permissions, aaaaand getting the k8s Dashbaord showing the CPU and Memory stats from Heapster as seen in the Dashboard pic of the pod statuses above…. phew!

Kubernetes – adding Helm and Tiller and deploying a Chart

Introduction

This is Step 2 in my recent series of Kubernetes blog posts.

Step 0 covers the initial host creation and basic provisioning with Ansible: https://www.donaldsimpson.co.uk/2019/01/03/kubernetes-setting-up-the-hosts/

Step 1 details the Kubernetes install and putting the cluster together, as well as reprovisioning it: https://www.donaldsimpson.co.uk/2018/12/29/kubernetes-from-cluster-reset-to-up-and-running/

Caveat

My aim here is to create a Kubernetes environment on my home lab that allows me to play with k8s and related technologies, then quickly and easily rebuild the cluster and start over.

The focus here in on trying out new technologies and solutions and in automating processes, so in this particular context I am not at all bothered with security, High Availability, redundancy or any of the usual considerations.

Helm and Tiller

The quick start guide is very good: https://docs.helm.sh/using_helm/ and I used this as I went through the process of installing Helm, initializing Tiller and deploying it to my Kubernetes cluster, then deploying a first example Chart to the Cluster. The following are my notes from doing this, as I plan to repeat then automate the entire process and am bound to forget something later 🙂

From the Helm home page, Helm describes itself as

The package manager for Kubernetes

and states that

Helm is the best way to find, share, and use software built for Kubernetes.

I have been following this project for a while and it looks to live up to the hype – there’s a rapidly growing and pretty mature collection of Helm Charts available here: https://github.com/helm/charts/tree/master/stable which as you can see covers an impressive amount of things you may want to use in your own Kubernetes cluster.

Get the Helm and Tiller binaries

This is as easy as described – for my architecture it meant simply

wget https://storage.googleapis.com/kubernetes-helm/helm-v2.12.1-linux-amd64.tar.gz

and extract and copy the 2 binaries (helm & tiller) to somewhere in your path

I usually do a quick sanity test or 2 – e.g. running “which helm” as a non-root user and maybe check “helm –help” and “helm version” all say something sensible too.

Install Tiller

Helm is the Client side app that directs Tiller, which is the Server side part. Just like steering a ship… and stretching the Kubernetes nautical metaphors to the max.

Tiller can be installed to your k8s Cluster simply by running “helm init“, which should produce output like the following:


ansible@umaster:~/helm$ helm init
Creating /home/ansible/.helm
Creating /home/ansible/.helm/repository
Creating /home/ansible/.helm/repository/cache
Creating /home/ansible/.helm/repository/local
Creating /home/ansible/.helm/plugins
Creating /home/ansible/.helm/starters
Creating /home/ansible/.helm/cache/archive
Creating /home/ansible/.helm/repository/repositories.yaml
Adding stable repo with URL: https://kubernetes-charts.storage.googleapis.com
Adding local repo with URL: http://127.0.0.1:8879/charts
$HELM_HOME has been configured at /home/ansible/.helm.
Tiller (the Helm server-side component) has been installed into your Kubernetes Cluster
Please note: by default, Tiller is deployed with an insecure 'allow unauthenticated users' policy.
To prevent this, run `helm init` with the --tiller-tls-verify flag.
For more information on securing your installation see: https://docs.helm.sh/using_helm/#securing-your-helm-installation
Happy Helming

That should do it, and a quick check of running pods confirms we now have a tiller pod running inside the kubernetes cluster in the kube-system namespace:

ansible@umaster:~/helm$ sudo kubectl get pods --all-namespaces -o wide
NAMESPACE     NAME                              READY   STATUS    RESTARTS   AGE     IP             NODE       NOMINATED NODE   READINESS GATES
kube-system   coredns-86c58d9df4-mg8b9          1/1     Running   0          22h     10.244.0.11    umaster    <none>           <none>
kube-system   coredns-86c58d9df4-zv24d          1/1     Running   0          22h     10.244.0.10    umaster    <none>           <none>
kube-system   etcd-umaster                      1/1     Running   0          22h     192.168.0.46   umaster    <none>           <none>
kube-system   kube-apiserver-umaster            1/1     Running   0          22h     192.168.0.46   umaster    <none>           <none>
kube-system   kube-controller-manager-umaster   1/1     Running   0          22h     192.168.0.46   umaster    <none>           <none>
kube-system   kube-flannel-ds-amd64-2npnw       1/1     Running   0          14h     192.168.0.46   umaster    <none>           <none>
kube-system   kube-flannel-ds-amd64-lpphn       1/1     Running   0          7m13s   192.168.0.43   ubuntu01   <none>           <none>
kube-system   kube-proxy-b7rwv                  1/1     Running   0          22h     192.168.0.46   umaster    <none>           <none>
kube-system   kube-proxy-wqw8c                  1/1     Running   0          7m13s   192.168.0.43   ubuntu01   <none>           <none>
kube-system   kube-scheduler-umaster            1/1     Running   0          22h     192.168.0.46   umaster    <none>           <none>
kube-system   tiller-deploy-6f8d4f6c9c-v8k9x    1/1     Running   0          112s    10.244.1.21    ubuntu01   <none>           <none>

So far so nice and easy, and as per the docs the next steps are to do a repo update and a test chart install…

ansible@umaster:~/helm$ helm repo update
Hang tight while we grab the latest from your chart repositories…
…Skip local chart repository
…Successfully got an update from the "stable" chart repository
Update Complete. ⎈ Happy Helming!⎈
ansible@umaster:~/helm$ helm install stable/mysql
Error: no available release name found
ansible@umaster:~/helm$

Doh. A quick google makes that “Error: no available release name found” look like a k8s/helm version conflict, but the fix is pretty easy and detailed here: https://github.com/helm/helm/issues/3055


So I did as suggested, creating a service account cluster role binding and patch to deploy them to the kube-system namespace:

kubectl create serviceaccount --namespace kube-system tiller 
kubectl create clusterrolebinding tiller-cluster-rule --clusterrole=cluster-admin --serviceaccount=kube-system:tiller
kubectl patch deploy --namespace kube-system tiller-deploy -p '{"spec":{"template":{"spec":{"serviceAccount":"tiller"}}}}'

and all then went ok:

ansible@umaster:~/helm$ kubectl create serviceaccount --namespace kube-system tillerserviceaccount/tiller created 

ansible@umaster:~/helm$ kubectl create clusterrolebinding tiller-cluster-rule --clusterrole=cluster-admin --serviceaccount=kube-system:tillerclusterrolebinding.rbac.authorization.k8s.io/tiller-cluster-rule created

ansible@umaster:~/helm$ kubectl patch deploy --namespace kube-system tiller-deploy -p '{"spec":{"template":{"spec":{"serviceAccount":"tiller"}}}}'deployment.extensions/tiller-deploy patchedansible@umaster:~/helm$

From then on everything went perfectly and as described:

try the example mysql chart from here https://docs.helm.sh/using_helm/

like this:

helm install stable/mysql
and check with "helm ls"
helm lsansible@umaster:~/helm$ helm ls 
NAME REVISION UPDATED STATUS CHART APP VERSION NAMESPACEdunking-squirrel 1 Thu Jan 3 15:38:37 2019 DEPLOYED mysql-0.12.0 5.7.14 defaultansible@umaster:~/helm$
and all is groovy
list pods with ansible@umaster:~/helm$ sudo kubectl get pods --all-namespaces -o wide 

NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
default dunking-squirrel-mysql-bb478fc54-4c69r 0/1 Pending 0 105s
kube-system coredns-86c58d9df4-mg8b9 1/1 Running 0 22h 10.244.0.11 umaster
kube-system coredns-86c58d9df4-zv24d 1/1 Running 0 22h 10.244.0.10 umaster
kube-system etcd-umaster 1/1 Running 0 22h 192.168.0.46 umaster
kube-system kube-apiserver-umaster 1/1 Running 0 22h 192.168.0.46 umaster
kube-system kube-controller-manager-umaster 1/1 Running 0 22h 192.168.0.46 umaster
kube-system kube-flannel-ds-amd64-2npnw 1/1 Running 0 15h 192.168.0.46 umaster
kube-system kube-flannel-ds-amd64-lpphn 1/1 Running 0 45m 192.168.0.43 ubuntu01
kube-system kube-proxy-b7rwv 1/1 Running 0 22h 192.168.0.46 umaster
kube-system kube-proxy-wqw8c 1/1 Running 0 45m 192.168.0.43 ubuntu01
kube-system kube-scheduler-umaster 1/1 Running 0 22h 192.168.0.46 umaster
kube-system tiller-deploy-8485766469-62c22 1/1 Running 0 2m17s 10.244.1.22 ubuntu01 ansible@umaster:~/helm$

The MySQL pod is failing to start as it has persistent volume claims defined, and I’ve not set up default storage for that yet – that’s covered in the next step/post 🙂

If you want to use or delete that MySQL deployment all the details are in the rest of the getting started guide – for the above it would mean doing a ‘helm ls‘ then a ‘ helm delete <release-name> ‘ where <release-name> is ‘dunking-squirrel’ or whatever you have.

A little more on Helm

Just running out of the box Helm Charts is great, but obviously there’s a lot more you can do with Helm, from customising the existing Stable Charts to suit your needs, to writing and deploying your own Charts from scratch. I plan to expand on this in more detail later on, but will add and update some notes and examples here as I do:

You can clone the Helm github repo locally:

git clone https://github.com/kubernetes/charts.git

and edit the values for a given Chart:

vi charts/stable/mysql/values.yaml

then use your settings to override the defaults:

helm install --name=donmysql -f charts/stable/mysql/values.yaml stable/mysql

using a specified name makes installing and deleting much easier to automate:

helm del donmysql

and the Helm ‘release’ lifecycle is quite docker-like:

helm ls -a
helm del --purge donmysql

There are some Helm tips & tricks here that I’m working my way through:

https://github.com/helm/helm/blob/master/docs/charts_tips_and_tricks.md

in conjunction with this Bitnami doc:

https://docs.bitnami.com/kubernetes/how-to/create-your-first-helm-chart/


Conclusion

For me and for now, I’m just happy that Helm, Tiller and Charts are working, and I can move on to automating these setup steps and some testing to my overall pipelines. And sorting out the persistent volumes too. After that’s all done I plan to start playing around with some of the stable (and perhaps not so stable) Helm charts.

As they said, this could well be “the best way to find, share, and use software built for Kubernetes” – it’s very slick!

Kubernetes – setting up the hosts

Introduction

This is Step 0 in my recent Kubernetes setup where I very quickly describe the process followed to build and configure the basic requirements for a simple Kubernetes cluster.

Step 1 is here https://www.donaldsimpson.co.uk/2018/12/29/kubernetes-from-cluster-reset-to-up-and-running/

and Step 2 where I set up Helm and Tiller and deploy an initial chart to the cluster is coming very soon

The TL/DR

A quick summary should cover 99% of this, but I wanted to make sure I’d recorded my process/journey to get there – to cut a long story short, I ended up using this Ansible project:

https://github.com/DonaldSimpson/ansible-kubeadm


which I forked from the original here:

https://github.com/ben-st/ansible-kubeadm

on the 5 Ubuntu linux hosts I created by hand (the horror) on my VMWare ESX home lab server. I started off writing my own ansible playbook which did the job, then went looking for improvements and found the above fitted my needs perfectly.

The inventory file here: https://github.com/DonaldSimpson/ansible-kubeadm/blob/master/inventory details the addresses and functions of the 5 hosts – 4 x workers and a single master, which I’m planning on keeping solely for master role.

My notes:

Host prerequisites are in my rough notes below – simple things like ssh keys, passwwordless sudo from the ansible user, installing required tools like python, setting suitable ip addresses and adding the users you want to use. Also allocating suitable amounts of mem, cpu and disk – all of which are down to your preference, availability and expectations.

https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/

ubuntumaster is 192.168.0.46
su – ansible
check history

ansible setup

https://www.howtoforge.com/tutorial/setup-new-user-and-ssh-key-authentication-using-ansible/
1 x master  - sudo apt-get install open-vm-tools-desktop - sudo apt install openssh-server vim whois python ansible - export TERM=linux re https://stackoverflow.com/questions/49643357/why-p-appears-at-the-first-line-of-vim-in-iterm
 - /etc/hosts:
127.0.1.1       umaster
192.168.0.43    ubuntu01
192.168.0.44    ubuntu02
192.168.0.45    ubuntu03
// slave nodes need:ssh-rsa AAAAB3NzaC1y<snip>fF2S6X/RehyyJ24VhDd2N+Dh0n892rsZmTTSYgGK8+pfwCH/Vv2m9OHESC1SoM+47A0iuXUlzdmD3LJOMSgBLoQt ansible@umaster
added to root user auth keys in .ssh and apt install python ansible -y
//apt install python ansible -y
useradd -m -s /bin/bash ansible
passwd ansible <type the password you want>

echo  -e ‘ansible\tALL=(ALL)\tNOPASSWD:\tALL’ > /etc/sudoers.d/ansibleecho  -e 'don\tALL=(ALL)\tNOPASSWD:\tALL' > /etc/sudoers.d/don
mkpasswd --method=SHA-512 <type password "secret">
Password:
$6$dqxHiCXHN<snip>rGA2mvE.d9gEf2zrtGizJVxrr3UIIL9Qt6JJJt5IEkCBHCnU3nPYH/
su - ansible
ssh-keygen -t rsa

cd ansible01/
vim inventory.ini
ansible@umaster:~/ansible01$ cat inventory.ini
[webserver]
ubuntu01 ansible_host=192.168.0.43
ubuntu02 ansible_host=192.168.0.44
ubuntu03 ansible_host=192.168.0.45

ansible@umaster:~/ansible01$ cat ansible.cfg
[defaults]
 inventory = /home/ansible/ansible01/inventory.ini
ansible@umaster:~/ansible01$ ssh-keyscan 192.168.0.43 >> ~/.ssh/known_hosts
# 192.168.0.43:22 SSH-2.0-OpenSSH_7.6p1 Ubuntu-4
# 192.168.0.43:22 SSH-2.0-OpenSSH_7.6p1 Ubuntu-4
# 192.168.0.43:22 SSH-2.0-OpenSSH_7.6p1 Ubuntu-4
ansible@umaster:~/ansible01$ ssh-keyscan 192.168.0.44 >> ~/.ssh/known_hosts
# 192.168.0.44:22 SSH-2.0-OpenSSH_7.6p1 Ubuntu-4
# 192.168.0.44:22 SSH-2.0-OpenSSH_7.6p1 Ubuntu-4
# 192.168.0.44:22 SSH-2.0-OpenSSH_7.6p1 Ubuntu-4
ansible@umaster:~/ansible01$ ssh-keyscan 192.168.0.45 >> ~/.ssh/known_hosts
# 192.168.0.45:22 SSH-2.0-OpenSSH_7.6p1 Ubuntu-4
# 192.168.0.45:22 SSH-2.0-OpenSSH_7.6p1 Ubuntu-4
# 192.168.0.45:22 SSH-2.0-OpenSSH_7.6p1 Ubuntu-4
ansible@umaster:~/ansible01$ cat ~/.ssh/known_hosts
or could have donefor i in $(cat list-hosts.txt)
do
ssh-keyscan $i >> ~/.ssh/known_hosts
done
cat deploy-ssh.yml

 – hosts: all
   vars:
     – ansible_password: ‘$6$dqxHiCXH<kersnip>l.urCyfQPrGA2mvE.d9gEf2zrtGizJVxrr3UIIL9Qt6JJJt5IEkCBHCnU3nPYH/’
  gather_facts: no
   remote_user: root

   tasks:

   – name: Add a new user named provision
     user:
          name=ansible
          password={{ ansible_password }}

   – name: Add provision user to the sudoers
     copy:
          dest: “/etc/sudoers.d/ansible”
          content: “ansible ALL=(ALL)  NOPASSWD: ALL”

   – name: Deploy SSH Key
     authorized_key: user=ansible
                     key=”{{ lookup(‘file’, ‘/home/ansible/.ssh/id_rsa.pub’) }}”
                     state=present

   – name: Disable Password Authentication
     lineinfile:
           dest=/etc/ssh/sshd_config
           regexp=’^PasswordAuthentication’
           line=”PasswordAuthentication no”
           state=present
           backup=yes
     notify:
       – restart ssh

   – name: Disable Root Login
     lineinfile:
           dest=/etc/ssh/sshd_config
           regexp=’^PermitRootLogin’
           line=”PermitRootLogin no”
           state=present
           backup=yes
     notify:
       – restart ssh

   handlers:
   – name: restart ssh
     service:
       name=sshd
       state=restarted

// end of the above file

ansible-playbook deploy-ssh.yml –ask-pass
results inLAY [all] *********************************************************************************************************************************************************************************************************************************************************************

TASK [Add a new user named provision] ******************************************************************************************************************************************************************************************************************************************
fatal:

[ubuntu02]

: FAILED! => {"msg": "to use the 'ssh' connection type 
with passwords, you must install the sshpass program"}
for each node/slave/hostsudo apt-get install -y sshpass
ubuntu01 ansible_host=192.168.0.43
ubuntu02 ansible_host=192.168.0.44
ubuntu03 ansible_host=192.168.0.45

kubernetes setup
https://www.techrepublic.com/article/how-to-quickly-install-kubernetes-on-ubuntu/run install_apy.yml against all hosts and localhost too
on master:

kubeadm init

results in:root@umaster:~# kubeadm init
[init] using Kubernetes version: v1.11.1
[preflight] running pre-flight checks
I0730 15:17:50.330589   23504 kernel_validator.go:81] Validating kernel version
I0730 15:17:50.330701   23504 kernel_validator.go:96] Validating kernel config
    [WARNING SystemVerification]: docker version is greater than the most recently validated version. Docker version: 17.12.1-ce. Max validated version: 17.03
[preflight] Some fatal errors occurred:
    [ERROR Swap]: running with swap on is not supported. Please disable swap
[preflight] If you know what you are doing, you can make a check non-fatal with `–ignore-preflight-errors=…`
root@umaster:~#
doswapoff -a then try again
kubeadm init… wait for images to be pulled etc – takes a while

Your Kubernetes master has initialized successfully!

To start using your cluster, you need to run the following as a regular user:

  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

You should now deploy a pod network to the cluster.
Run “kubectl apply -f [podnetwork].yaml” with one of the options listed at:
https://kubernetes.io/docs/concepts/cluster-administration/addons/

You can now join any number of machines by running the following on each node
as root:

  kubeadm join 192.168.0.46:6443 --token 9e85jo.77nzvq1eonfk0ar6 --discovery-token-ca-cert-hash sha256:61d4b5cd0d7c21efbdf2fd64c7bca8f7cb7066d113daff07a0ab6023236fa4bc
root@umaster:~#

Next up…

The next post in the series is here: https://www.donaldsimpson.co.uk/2018/12/29/kubernetes-from-cluster-reset-to-up-and-running/ and details an automated process to scrub my cluster and reprovision it (form a Kubernetes point of view – the hosts are left intact).

Kubernetes – from cluster reset to up and running

These are notes on going from a freshly reset kubernetes cluster to a running & healthy cluster with a pod network applied and worker nodes connected.

To get to this starting point I provisioned 4 Ubuntu hosts (1 master & 3 workers) on my VMWare server – a Dell Poweredge R710 with 128GB RAM.

I then used this Ansible project:

https://github.com/DonaldSimpson/ansible-kubeadm

to configure the hosts and prep for Kubernetes with kubeadm:

I’ll write about this in more detail in another post…

Please note that none of this is production grade or recommended, it’s simply what I have done to suit my needs in my home lab. My focus is on automating Kubernetes processes and deployments, not creating highly available bullet-proof production systems.

To reset and restore a ‘new’ cluster, first on the master instance – reboot and as a normal user (I’m using an “ansible” user with sudo throughout):


sudo kubeadm reset
(y)
sudo swapoff -a
sudo kubeadm init --pod-network-cidr=10.244.0.0/16

I’m passing that CIDR address as I’m using Flannel for pod networking (details follow) – if you use something else you may not need that, but may well need something else.

That should be the MASTER started, with a message to add nodes with:


  kubeadm join 192.168.0.46:6443 --token 9w09pn.9i9uu1ht8gzv36od --discovery-token-ca-cert-hash sha256:4bb0bbb1033a96347c6dd888c769ec9c5f6caa1b699066a58720ffdb97a0f3d7

which all sounds good, but the first most basic check produces the following error:


ansible@umaster:~$ kubectl cluster-info
To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
Unable to connect to the server: x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "kubernetes")

which I think is due to the kubeadm reset cleaning up the previous config, but can be easily fixed with this:


mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

then it works and MASTER is up and running ok:


ansible@umaster:~$ sudo kubectl cluster-info
Kubernetes master is running at https://192.168.0.46:6443
KubeDNS is running at https://192.168.0.46:6443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.

————- ADD NODES ——————

Use the command and token provided by the master on the worker node(s) (in my case that’s “ubuntu01” to “ubuntu04”). Again I’m running as the ansible user everywhere, and I’m disabling swap and doing a kubeadm reset first as I want this repeatable:

sudo swapoff -a
sudo kubeadm reset
sudo  kubeadm join 192.168.0.46:6443 --token 9w09pn.9i9uu1ht8gzv36od --discovery-token-ca-cert-hash sha256:4bb0bbb1033a96347c6dd888c769ec9c5f6caa1b699066a58720ffdb97a0f3d7

I think the token expires after a few hours. If you want to get a new one you can query the Master using:

https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-token/

Or, as I’ve just found out, the more recent versions ok k8s provide “kubeadm token create –print-join-command”, which provide output like the following example that you can save to a file/variable/whatever:

kubeadm join 192.168.0.46:6443 --token 8z5obf.2pwftdav48rri16o --discovery-token-ca-cert-hash sha256:2fabde5ad31a6f911785500730084a0e08472bdcb8cf935727c409b1e94daf44

I believe options to specify json or alternative output formatting is in the works too.

That’s all that is needed, if you’ve not used this node already it may take a while to pull things in but if you have it should be pretty much instant.

When ready, running a quick check on the MASTER shows the connected node (ubuntu01) and the Master (umaster) and their status:


ansible@umaster:~$ sudo kubectl get nodes --all-namespaces
NAME       STATUS     ROLES    AGE     VERSION
ubuntu01   NotReady   <none>   27s     v1.13.1
umaster    NotReady   master   8m26s   v1.13

The NotReady status is because there’s no pod network available – see here for details and options:

https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/#pod-network

so apply a pod network (I’m using flannel) like this on the Master only:


ansible@umaster:~$ sudo kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/bc79dd1505b0c8681ece4de4c0d86c5cd2643275/Documentation/kube-flannel.yml
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.extensions/kube-flannel-ds-amd64 created
daemonset.extensions/kube-flannel-ds-arm64 created
daemonset.extensions/kube-flannel-ds-arm created
daemonset.extensions/kube-flannel-ds-ppc64le created
daemonset.extensions/kube-flannel-ds-s390x created

Then check again and things should look better now they can communicate…


ansible@umaster:~$ sudo kubectl get nodes --all-namespaces
NAME       STATUS   ROLES    AGE     VERSION
ubuntu01   Ready    <none>   2m23s   v1.13.1
umaster    Ready    master   10m     v1.13.1
ansible@umaster:~$

Adding any number of subsequent nodes is very easy and exactly the same (the pod networking setup is a one-off step on the master only). I added all 4 of my worker vms and checked they were all Ready and “schedulable”. My server coped with this no problem at all. Note that by default you can’t schedule tasks on the Master, but this can be changed if you want to.

That’s the very basic “reset and restore” steps done. I plan to add this process to a Jenkins Pipeline, so that I can chain a complete cluster destroy/reprovision and application build, deploy and test process together.

The next steps I did were to:

  • install the Kubernetes Dashboard to the cluster
  • configure the Kubernetes Dashboard and fix permissions
  • deploy a sample application, replicaset & service and expose it to the network
  • configure Heapster

which I’ll post more on soonish… and I’ll add the precursor to this post on the host provisioning and kubeadm setup too.

Meetup – Deploying Openshift to AWS with HashiCorp Terraform and Ansible

 

Automated IT Solutions presented a talk on “Deploying Openshift to AWS with HashiCorp Terraform and Ansible”, by Liam Lavelle on 16th October 2018.

 

We would like to thank

 

  • Liam Lavelle for an interesting, informative and fun session
  • Everyone that came along to make it such a good event, with some great questions, helpful answers and interesting discussions
  • Hays for the beer, pizza, venue and help with everything

Hope to see you all at the next one soon!

The slides and all materials used in this session are available on our GitHub repo here:

 

Deploying Openshift to AWS with HashiCorp Terraform and Ansible

Tuesday, Oct 16, 2018, 6:15 PM

HAYS
7 Castle St, Edinburgh EH2 3AH Edinburgh, GB

30 Members Went

In this session we look at Infrastructure as Code and Configuration as Code, as we demonstrate how to use these approaches to deploy RedHat OpenShift to AWS with HashiCorp Terraform and Ansible. We start off with configuring AWS credentials, then use HashiCorp Terraform to create the AWS infrastructure needed to deploy and run our own RedHat OpenSh…

Check out this Meetup →

 

Here are the details:
When:
Tuesday, October 16th, 2018
6:15 PM to 9:00 PM

 

Where:
Hays office on the 2nd floor
7 Castle St, Edinburgh EH2 3AH · Edinburgh

 

What:
Deploying Openshift to AWS with HashiCorp Terraform and Ansible

 

Agenda:

In this session we look at Infrastructure as Code and Configuration as Code, as we demonstrate how to use these approaches to deploy RedHat OpenShift to AWS with HashiCorp Terraform and Ansible.

We start off with configuring AWS credentials, then use HashiCorp Terraform to create the AWS infrastructure needed to deploy and run our own RedHat OpenShift cluster.

We then go through using Ansible to deploy OpenShift to AWS, followed by a review of the Cluster, then take a quick look at troubleshooting any issues you may encounter.

There will be a break in the middle for beer & pizza courtesy of Hays, and we will wrap things up with a quick Q&A and feedback session.

If you would like to bring your own laptop and follow along, please do!

Who:
Intermediate Linux and some AWS knowledge is useful but not essential.