create helm chart

Introduction to Kubernetes Helm Charts

What is Helm?

In simple terms, Helm is a package manager for Kubernetes. Helm is the K8s equivalent of yum or apt. Helm deploys charts, which you can think of as a packaged application. It is a collection of all your versioned, pre-configured application resources which can be deployed as one unit. You can then deploy another version of the chart with a different set of configuration.

Helm helps in three key ways:

• Improves productivity
• Reduces the complexity of deployments of microservices
• Enables the adaptation of cloud native applications

Why use Helm?

Writing and maintaining Kubernetes?YAML manifests?for all the required Kubernetes objects can be a time consuming and tedious task. For the simplest of deployments, you would need at least 3 YAML manifests with duplicated and hardcoded values. Helm simplifies this process and creates a single package that can be advertised to your cluster.

Helm?is a client/server application and, until recently, has relied on Tiller (the helm server) to be deployed in your cluster. This gets installed when installing/initializing helm on your client machine. Tiller simply receives requests from the client and installs the package into your cluster. Helm can be easily compared to RPM of DEB packages in Linux, providing a convenient way for developers to package and ship an application to their end users to install.

What are Helm charts?

Helm Charts are simply Kubernetes YAML manifests combined into a single package that can be advertised to your Kubernetes clusters. Once packaged, installing a Helm Chart into your cluster is as easy as running a single?helm install, which really simplifies the deployment of containerized applications.

Describing Helm

Helm has two parts to it:

• The client (CLI), which lives on your local workstation.
• The server (Tiller), which lives on the Kubernetes cluster to execute what’s needed.

The idea is that you use the CLI to push the resources you need and tiller will make sure that state is in fact the case by creating/updating/deleting resources from the chart. To fully grasp helm, there are 3 concepts we need to get familiar with:

• Chart: A package of pre-configured Kubernetes resources.
• Release: A specific instance of a chart which has been deployed to the cluster using Helm.
• Repository: A group of published charts which can be made available to others.

Benefits of Helm

Developers like Helm charts for many reasons:

Boosts productivity

Software engineers are good at writing software, and their time is best spent doing just that. Using Helm allows software to deploy their test environments at the click of a button.

An example of this might be that, in order to test a new feature, an engineer needs a SQL database. Instead of going through the process of installing the software locally, creating the databases and tables required, the engineer can simply run a single?Helm Install?command to create and prepare the database ready for testing.

Reduces duplication & complexity

Once the chart is built once, it can be used over and over again and by anyone. The fact that you can use the same chart for any environment reduces complexity of creating something for dev, test and prod. You can simply tune you chart and make sure it is ready to apply to any environment. And you get the benefit of using a production ready chart in dev.

Smooths the K8S learning curve

It’s no secret that the learning curve for Kubernetes and containers is long for your average developer. Helm simplifies that learning curve: developers do not require a full, detailed understanding of the function of each Kubernetes object in order to start developing and deploying container applications.

Helm easily integrates into?CI/CD pipelines?and allows software engineers to focus on writing code—not deploying applications.

Simplifies deployments

Helm Charts make it easy to set overridable defaults in the?values.yaml?file, allowing software vendors or administrators of charts to define a base setting. Developers and users of charts can override these settings when installing their chart to suit their needs. If the default installation is required, then no override is required.

Deploying applications to Kubernetes? is not a straightforward process, with different objects being tightly coupled. This required specific knowledge of these objects and what their functions are in order to be able to successfully deploy. Helm takes the complexity out of that doing much of the hard work for you.

Describing a Helm chart

Helm has a certain structure when you create a new chart. To create, run “helm create YOUR-CHART-NAME”. Once this is created, the directory structure should look like:

• .helmignore: This holds all the files to ignore when packaging the chart. Similar to?.gitignore, if you are familiar with git.
• Chart.yaml: This is where you put all the information about the chart you are packaging. So, for example, your version number, etc. This is where you will put all those details.
• Values.yaml: This is where you define all the values you want to inject into your templates. If you are familiar with terraform, think of this as helms variable.tf file.
• Charts: This is where you store other charts that your chart depends on. You might be calling another chart that your chart need to function properly.
• Templates: This folder is where you put the actual manifest you are deploying with the chart. For example you might be deploying an nginx deployment that needs a service, configmap and secrets. You will have your deployment.yaml, service.yaml, config.yaml and secrets.yaml all in the template dir. They will all get their values from values.yaml from above.

Installing Helm and configuring Helm Charts

Installing and configuring Helm for your K8S cluster is a very quick and straight forward process—there are multiple versions of Helm that can be installed (v1/v2 and most recently v3), all of which can be configured to your organization’s needs. Check out the?getting started page?for instructions on downloading and installing Helm.

How To Create A Helm Chart:?step-by-step instructions to create and deploy a Helm chart.

Create Helm Chart

Step 1: Create a New Helm Chart

helm create <chart name>

For example:

helm create phoenixnap

2. Using the?ls command, list the chart structure:

• Directory?charts?– Used for adding dependent charts. Empty by default.
• Directory?templates?– Configuration files that deploy in the cluster.
• YAML?file?– Outline of the Helm chart structure.
• YAML?file?– Formatting information for configuring the chart.

Step 2: Configure Helm Chart Image Pull Policy

. Open the?values.yaml?file in a?text editor. Locate the?image?values:

There are three possible values for the?pullPolicy:

• IfNotPresent?– Downloads a new version of the image if one does not exist in the cluster.
• Always?– Pulls the image on every restart or deployment.
• Latest?– Pulls the most up-to-date version available.

2. Change the image?pullPolicy?from?IfNotPresent?to?Always:

Step 3: Helm Chart Name Override

Overriding the Helm chart name ensures configuration files also change.

Step 4: Specify Service Account Name

2. Specify the?name?of the service account:

Step 5: Change Networking Service Type

The recommended networking service type for Minikube is?NodePort.

1. To change the networking service type, locate the?service?value:

2. Change the?type?from?ClusterIP?to?NodePort:

Deploy Helm Chart

After configuring the?values.yaml?file, check the status of your Minikube cluster and deploy the application using?Helm commands.

Step 1: Check minikube Status

If Minikube isn’t running, the install Helm chart step returns an error.

1. Check Minikube status with:

2. If the status shows?Stopped, run

minikube start

The output shows?Done?and the status changes to?Running.

Step 2: Install the Helm Chart

Install the Helm chart using the?helm install?command:

helm install <full name override> <chart name>/ --values <chart name>/values.yaml

For example:

helm install phoenix-chart phoenixnap/ --values phoenixnap/values.yaml

The?helm install?command deploys the app. The next steps are printed in the?NOTES?section of the output

Step 3: Export the Pod Node Port and IP Address

1. Copy the two?export?commands from the?helm install?output.

2. Run the commands to get the Pod node port and IP address:

Step 4: View the Deployed Application

thank you !!!!!!!!!!!!!!!!!!