Kubernetes Basics Training

Web terminal

Mon, 01 Jan 0001 00:00:00 +0000

Using OpenShift’s web terminal might be more convenient for you as it doesn’t require you to install kubectl locally on your computer.

Note

If you do change your mind, head right over to 1. Local usage.

First of all, open your browser. Then, log in on OpenShift’s web console using the URL and credentials provided by your trainer.

Task 2: Initialize terminal

Warning

Make sure to create a dedicated project for the web terminal!

In OpenShift’s web console:

Footer

Mon, 01 Jan 0001 00:00:00 +0000

Header

Mon, 01 Jan 0001 00:00:00 +0000

- acend gmbh

Windows

Mon, 01 Jan 0001 00:00:00 +0000

Installation for Windows

Follow the steps outlined in https://kubernetes.io/docs/tasks/tools/install-kubectl/ .

In case the installation from the official package repositories didn’t work (or a specific version is needed) the static binary can be downloaded and put into the following path:

C:\Kubernetes\

In Windows, the PATH can be set in the advanced system settings. It depends on the version:

Note: Windows Quick Hack

Copy the kubectl binary directly into the folder C:\Windows.

YAML

Mon, 01 Jan 0001 00:00:00 +0000

YAML Ain’t Markup Language (YAML) is a human-readable data-serialization language. YAML is not a programming language. It is mostly used for storing configuration information.

Note

Data serialization is the process of converting data objects, or object states present in complex data structures, into a stream of bytes for storage, transfer, and distribution in a form that can allow recovery of its original structure.

As you will see a lot of YAML in our Kubernetes basics course, we want to make sure you can read and write YAML. If you are not yet familiar with YAML, this introduction is waiting for you. Otherwise, feel free to skip it or come back later if you meet some less familiar YAML stuff.

macOS

Mon, 01 Jan 0001 00:00:00 +0000

Installation for macOS

Follow the steps outlined in https://kubernetes.io/docs/tasks/tools/install-kubectl/ .

In case the installation from the official package repositories didn’t work (or a specific version is needed) the static binary can be downloaded and put into the following path:

~/bin

File mode

The kubectl binary has to be executable:

cd ~/bin
chmod +x kubectl

PATH variable

In macOS, the directory ~/bin should already be part of the PATH variable. In case kubectl is placed in a different directory, you can change the PATH variable with the following command:

Linux

Mon, 01 Jan 0001 00:00:00 +0000

Installation for Linux

Follow the steps outlined in https://kubernetes.io/docs/tasks/tools/install-kubectl/ .

In case the installation from the official package repositories didn’t work (or a specific version is needed) the static binary can be downloaded and put into the following path:

~/bin

File mode

The kubectl binary has to be executable:

cd ~/bin
chmod +x kubectl

PATH variable

In Linux, the directory ~/bin should already be part of the PATH variable. In case kubectl is placed in a different directory, you can change the PATH variable with the following command:

Console login

Mon, 01 Jan 0001 00:00:00 +0000

First of all, open your browser. Then, log in on OpenShift’s web console using the URL and credentials provided by your trainer.

In order to log in on the command line, copy the login command from the web console.

To do that, open the Web Console and click on your username that you see at the top right, then choose Copy Login Command.

Verification

Mon, 01 Jan 0001 00:00:00 +0000

Verify the installation

You should now be able to execute kubectl in the command prompt. To test, execute:

kubectl version

You should now see something like (the version number may vary):

Client Version: version.Info{Major:"1", Minor:"18", GitVersion:"v1.18.0", GitCommit:"9e991415386e4cf155a24b1da15becaa390438d8", GitTreeState:"clean", BuildDate:"2020-03-25T14:58:59Z", GoVersion:"go1.13.8", Compiler:"gc", Platform:"linux/amd64"}
...

If you don’t see a similar output, possibly there are issues with the PATH variable.

Warning

Make sure to use at least version 1.16.x for your kubectl

First steps with kubectl

The kubectl binary has many subcommands. Invoke kubectl --help (or simply -h) to get a list of all subcommands; kubectl <subcommand> --help gives you detailed help about a subcommand.

Optional Kubernetes power tools

Mon, 01 Jan 0001 00:00:00 +0000

Optional Kubernetes power tools

kubectx and kubens are two handy shell scripts which let you easily switch between Kubernetes contexts and namespaces. See https://github.com/ahmetb/kubectx for detailed instructions.

Installation of kubectx and kubens:

curl https://raw.githubusercontent.com/ahmetb/kubectx/master/kubectx -o ~/bin/kubectx
curl https://raw.githubusercontent.com/ahmetb/kubectx/master/kubens -o ~/bin/kubens
chmod +x ~/bin/kubectx ~/bin/kubens

kube-ps1 is another helpful shell script which adds the current context and namespace to the shell prompt: https://github.com/jonmosco/kube-ps1

fzf is yet another handy helper tool when you have to deal with a lot of contexts or namespaces by adding an interactive menu to kubectx and kubens: https://github.com/junegunn/fzf

Other ways to work with OpenShift

Mon, 01 Jan 0001 00:00:00 +0000

Other ways to work with OpenShift

If you don’t have access to a running OpenShift development environment (anymore), there are several options to get one.

OpenShift Developer Sandbox : 30 days of no-cost access to a shared cluster on OpenShift
OpenShift Local : A local OpenShift environmennt running on your machine
OKD single node installation : OKD (OpenShift community edition) single node installation

Next steps

When you’re ready to go, head on over to the labs and begin with the training!

Helm overview

Mon, 01 Jan 0001 00:00:00 +0000

Ok, let’s start with Helm. First, you have to understand the following 3 Helm concepts: Chart, Repository and Release.

A Chart is a Helm package. It contains all of the resource definitions necessary to run an application, tool, or service inside of a Kubernetes cluster. Think of it like the Kubernetes equivalent of a Homebrew formula, an Apt dpkg, or a Yum RPM file.

A Repository is the place where charts can be collected and shared. It’s like Perl’s CPAN archive or the Fedora Package Database, but for Kubernetes packages.

CLI installation

Mon, 01 Jan 0001 00:00:00 +0000

This guide shows you how to install the helm CLI tool. helm can be installed either from source or from pre-built binary releases. We are going to use the pre-built releases. helm binaries can be found on Helm’s release page for the usual variety of operating systems.

Warning

If you do this training in our acend web based environment, no installation is required.

Task 12.2.1: Install CLI

Install the CLI for your Operating System

Create a chart

Mon, 01 Jan 0001 00:00:00 +0000

In this lab we are going to create our very first Helm chart and deploy it.

Task 12.3.1: Create Chart

First, let’s create our chart. Open your favorite terminal and make sure you’re in the workspace for this lab, e.g. cd ~/<workspace-kubernetes-training>:

helm create mychart

You will now find a mychart directory with the newly created chart. It already is a valid and fully functional chart which deploys an nginx instance. Have a look at the generated files and their content. For an explanation of the files, visit the Helm Developer Documentation . In a later section you’ll find all the information about Helm templates.

Generic Chart setup

Mon, 01 Jan 0001 00:00:00 +0000

In the following labs we are going to create our first Helm Charts with the help of Baloise’s Generic Chart and deploy them.

Baloise’s Generic Helm Chart is meant as a template and easy starting point to deploy common Kubernetes resource manifests. By declaring the Generic Chart as a dependency of your own Chart, you can make use of all the features the Generic Chart offers.

Task 1: Setup the dependency

So first, let’s create your own Chart. Open your favorite terminal and make sure you’re in the workspace for this lab, e.g. cd ~/<workspace-kubernetes-training>:

A first example using the Generic Chart

Mon, 01 Jan 0001 00:00:00 +0000

You’re now all set to begin with a first example!

Task 1: Create a `values.yaml` file

Still inside your mychart Helm Chart directory, open the already existing values.yaml file. Inside you’ll find a host of defined parameters. Delete them all.

Instead, fill in the following content:

first-example-app:
 replicaCount: 1
 image:
 repository: REGISTRY-URL/example/nginx-sample
 tag: latest
 pullPolicy: IfNotPresent
 ingress:
 controller: Route
 clusterName: CLUSTER-NAME
 network:
 http:
 servicePort: 8080
 ingress:
 clusterName: CLUSTER-NAME
 readinessProbe:
 httpGet:
 path: /
 port: 8080
 initialDelaySeconds: 5
 timeoutSeconds: 1
 resources:
 requests:
 cpu: 10m
 memory: 16Mi
 limits:
 cpu: 200m
 memory: 32Mi

Task 2: A first test

Before applying anything to the cluster, you should test if the current values have the desired effect. In order to do so, execute the following command:

Complex example

Mon, 01 Jan 0001 00:00:00 +0000

In this extended lab, we are going to deploy an existing, more complex application with a Helm chart from the Artifact Hub.

Artifact Hub

Check out Artifact Hub where you’ll find a huge number of different Helm charts. For this lab, we’ll use the WordPress chart by Bitnami , a publishing platform for building blogs and websites.

WordPress

As this WordPress Helm chart is published in Bitnami’s Helm repository, we’re first going to add it to our local repo list:

Generic Chart usage

Mon, 01 Jan 0001 00:00:00 +0000

You have now seen how to set up and use the Generic Chart. Now it’s your turn!

Task 1: Setup

Repeat the steps from Generic Chart setup in order to create a new Chart.

Note

Note the alias: line inside Chart.yaml. You can change this value to whatever you’d like, but you need to use the same name as first line inside your values.yaml!

This is also how you can use the Generic Chart multiple times if you have more than one app/component.

Kubernetes Basics Training

Web terminal

Note

Task 1: Login on the web console

Task 2: Initialize terminal

Warning

Footer

Header

Windows

Installation for Windows

Note: Windows Quick Hack

YAML

Note

macOS

Installation for macOS

File mode

PATH variable

Linux

Installation for Linux

File mode

PATH variable

Console login

Task 1: Login on the web console

Task 2: Login on the command line

Verification

Verify the installation

Warning

First steps with kubectl

Optional Kubernetes power tools

Optional Kubernetes power tools

Other ways to work with OpenShift

Other ways to work with OpenShift

Next steps

Helm overview

CLI installation

Warning

Task 12.2.1: Install CLI

Create a chart

Task 12.3.1: Create Chart

Generic Chart setup

Task 1: Setup the dependency

A first example using the Generic Chart

Task 1: Create a values.yaml file

Task 2: A first test

Complex example

Artifact Hub

WordPress

Generic Chart usage

Task 1: Setup

Note

Task 1: Create a `values.yaml` file