Application Deployment to AKS using HELM Chart...HELM Chart Deployment Steps - Step#5: CD Pipeline...

1 | Copyright © 2018 HCL Technologies | www.hcltech.comCopyright © 2018 HCL Technologies Limited | www.hcltech.com

Application Deployment to AKS using HELM Chart – A POV

23rd August, 2019

2 | Copyright © 2018 HCL Technologies | www.hcltech.com

Application Deployment in Kubernetes

▪ An application in Kubernetes typically consists of at least two resource types:

A Deployment Resource - describes a set of pods to be deployed togetherA Services Resource - defines endpoints for accessing the APIs in those pods.

▪ An application can also include ConfigMaps, Secrets, and Ingress.

▪ For any deployment, we would need several Kubernetes commands (kubectl) to create and configure resources.

▪ A Helm chart helps us create many resources with a set of commands, instead of manually creating each

resource separately.

▪ A default chart has a minimum of a deployment template and a service template.


Typical Application Deployment Issues using Kubectl

▪ Deploying and maintaining multiple application to AKS using kubectl command is very difficult

▪ Deploying kubernetes applications including multiple YAML files using kubectl command is not easy

▪ Running multiple applications and maintaining ( Managing , Updating and Scaling ) them is very difficult task

▪ Rollback of kubernetes service application and updates through kubectl command is not easy

▪ Deploying kubernetes applications to multiple Environments ( Dev, QA & PROD ) with kubectl is very tedious job

▪ Using Kubernetes manifest file , we need to put a fixed values like Image name, version in the Kubernetes objects

YAML file for unique identification.


Possible Solutions

Using HELM Chart ( Kubernetes Package Manger )

• to create Pods / Services to communicate each pod; Deploy container image to Pod, Persistence volume for configuration data.

Using Terraform ( Infrastructure as Code )

• + Kubectl Command

1 2

Feature HELM Chart Terraform

Package Manager Packaging + Versioning + Storing No Packaging

IAC ( Infrastructure as Code ) Supports application deployments to Kubernetes. No Azure Resource can be createdthrough this.

Creating/Building, changing and versioning infrastructure safely including AKS.

Language Support GO templates JSON/HCL ( Hashi Corp Language) file format

Charts Versioning Every Chart release will have a version. NA

Reusable Components Templates can be reused. Use modules to reuse

Cloud Supported Google Cloud, IBM Cloud , Azure AKS , Amazon EKS

AWS, GCP, MS Azure


HELM Components

Chart (Templates)

Values (Config)

Release (Resources)

HELM

Kubernetes Cluster

•Helm: A command-line interface (CLI) that installs charts into Kubernetes, creating a release for each installation.

•Chart: An application package that contains templates for a set of resources which are necessary to run the application. A template uses variables that are substituted with values when the manifest is created. The chart includes a values file that describes how to configure the resources.

•Release: An instance of a chart that is running in a Kubernetes cluster.


Benefits of Using HELM Charts for Deployment

Cons

Pros

• Helps application deployment easy, standardized and reusable• Deploy and manage manifests in a production environment• Complex applications can be packaged together• Rollback or upgrade multiple objects together, • Reduces deployment complexity• Easily change parameters of templates, Allows user to edit the configuration values without

changing manifest files.

• Creating helm charts is rather complex • Helm Charts will install Server component in AKS called Tiller which manages the chart deployment • Two helm charts with same label they interfere with each other and damage the underlying resources.


Deployment through HELM Chart – A POC

Deploying a containerized Web App to Azure Kubernetes Cluster through HELM Chart using DevOps CI/CD

Prerequisites

– Web API application Code

– Docker Container Image

– HEML Chart deployment files ( Deployment, Service and so on )

AKS Deployment Architecture

This Deployment uses Helm to Create Pods, Services to communicate each pod, Deploy container image to Pod, Persistence volume for storing configuration data.

Scope


Configuration (Prerequisites) & Deployment Steps

Build the Docker Image (with the core appl. Binaries and

dependencies and host OS) and push it to ACR (or any other

registry) along with tags

Create a Docker file in the App code for single container (or create a Docker compose file for multi-

container)

Create ACR in Azure (either manually or through ARM template)

Configuration

Deployment Steps

Create AKS

Cluster

Verify Cluster

Create AKS

Resources

Configure CI Pipeline

Configure CD

Pipeline

Expose resources through External

Endpoints

Do AKS Resource

Health Check


HELM Chart – Deployment Step #1: Create AKS Cluster

1. Create a AKS Cluster through ARM templates since HELM chart does not create AKS ( Through DevOps CI/CD )


HELM Chart – Deployment Step #2: Verify Cluster Creation

2. Verify Cluster through AKS Dashboard – Plain Cluster gets created in Azure with additional steps required for application deployment


HELM Chart – Deployment Step #3: Creation of AKS Resources

▪ Create AKS resources using VS IDE –for each resource (network, deployment, service, loadbalancer, configuration,

persistence volumes, RBAC) respective kubernetes manifest / yaml file have to created.

Decide on type of resources to be created, based on requirement.

▪ Define load balancing technique, service endpoints, networking, security etc. through respective resources.

▪ Make the yaml files configurable through GO language referring to configurable values in values yaml file

▪ Create a HELM Chart template folder (with appropriate sub-folders – leverage standard HELM Chart templates

to have similar folder structure)

▪ All the yaml files have to be put in HELM Chart Templates folder of App code

3. Creation of AKS resources and deploying them in AKS


Create AKS Resources – yaml files for different resource types


Create AKS Resources – configuration yaml files using values.yaml

Changing Parameter values in Values.yaml file will reflect all the reference yaml files in Chart Folder


Create AKS Resources – Leverage HELM Chart Templates


Create AKS Resources – Chart Template Folder

Each Application will have a Chart folder to manage Release Version and can store in ACR


HELM Chart Deployment Steps - Step#4: CI Pipeline

• Create or reuse ACR Resource (reuse manually created ACR through above steps)

• Build Task to build and push Docker image to ACR

• Create a HELM task in CI pipeline to make a HELM Package (for better rollback process we can push this to ACR as a repository)

• Copy the ARM template files to CD pipeline (build configuration folder) for creation of Azure resources AKS and ACR


CI Pipeline – List of Chart Files in Repositories (ACR)


HELM Chart Deployment Steps - Step#5: CD Pipeline

• Create AKS cluster or reuse existing cluster

• Install HELM Tiller into AKS• Pull the docker container

image from ACR• HELM upgrade – refer to

the HELM package created in CI pipeline

Once HELM package is run, respective appl. Binaries/dependencies will be deployed to respective clusters as defined through deployment/service/ loadbalancer/ network yamlfiles.(required set of pods per node of a cluster will be created dynamically through this deployment and these pods will run the appl. instances)


HELM Chart Deployment Step#6: Services Exposed via External Endpoints

• Get external IP of the service endpoints through kubectl commands

• Access the required resources through these endpoints


HELM Chart Deployment Step#7: Health Check using AKS Dashboards

Do health checks through Azure AKS dashboard – to verify Deployments, PODs, Replica sets


POC - Learning

# Issue Workaround Solution

1.Two helm charts cannot have same label which can impact underlying resources

While putting the label , ensure that it is not duplicated.

2. Timeout in helm upgrade task Increased timeout number (but didn’t solve for all cases)

3. Unable to access service outside cluster Get the service LB IP through kubectl command

4.Improper Indentation of Helm File will createrendering issue

Make sure User need to validate the helm files before deploying


References

1. https://helm.sh/docs/developing_charts/#charts

3. https://boxboat.com/2018/09/19/helm-and-kubernetes-deployments/

4. https://developer.epages.com/blog/tech-stories/kubernetes-deployments-with-helm/

2. https://kubernetes.io/docs/concepts/

5. https://helm.sh/docs/chart_template_guide/

https://helm.sh/docs/developing_charts/#chartshttps://boxboat.com/2018/09/19/helm-and-kubernetes-deployments/https://developer.epages.com/blog/tech-stories/kubernetes-deployments-with-helm/https://kubernetes.io/docs/concepts/https://helm.sh/docs/chart_template_guide/

$7.3 BILLION ENTERPRISE | 119,000 IDEAPRENEURS | 32 COUNTRIES
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