Application Deployment to AKS Cluster Using Kubernetes Plugin

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Objective

The goal of this tutorial is to deploy manifest files on an Azure Kubernetes Service (AKS) cluster through FlexDeploy using the Kubernetes Plugin. For this tutorial, we will be setting up an automated deployment of an Nginx Application using the manifest yaml files which are present in a Git repository. The steps will include:

• Configuring properties e.g. config file path, cloud account, and CLI path
• Cloning the manifest files from a Git repository
• Deploying the Nginx Application to an AKS cluster
• Verifying the application is successfully created on the AKS cluster

We will walk through each of the FlexDeploy features that will be created/configured to accomplish this goal and have the Nginx Application deployed on the AKS cluster in a very short amount of time.

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Checklist

Checklist	Description
Azure Tenant Id	Azure Tenant Id for the company
Azure Subscription Id	Azure Subscription where the AKS cluster exists
Azure Client ID	Client ID to connect to desired Azure Subscription
Azure Client Key	Password for the Client ID
Azure Client ID permission	The Client ID must have relevant access in AKS cluster to do the deployment
Azure CLI installation	Azure CLI needs to be installed where the plugin operation shall run (e.g. FlexDeploy server)
Azure CLI in class path	Azure CLI should be added to class path on the FlexDeploy Server. Else the path can also be set under FlexDeploy environment level property
AKS Setup	AKS cluster should be created in Azure and a kubeconfig file should be present with the context of the cluster.

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Configure Cloud Account

To connect with AKS cluster, we required to configure Cloud account, with credential details. Configure Azure Cloud Account under Integration. FlexDeploy will connect to the AKS cluster and deploy the Nginx Application.

1. Navigate to the Integrations
2. Select Cloud from the left-hand pane
3. Create a new Cloud account with the “+” button. Create a new Cloud account of provider type “Azure”

It should have a Client ID, Client Key, Tenant Id, and Subscription Id configured in it. The Client ID must have relevant access to do the deployment on AKS cluster.

1. Client Key is a password field and hence needs to be kept hidden. To update it, click on the pencil icon as shown below
2. Update the Client Key value under Secret Text. This is to make sure no one else can retrieve the password

After configuration we would be able to use the Cloud Account as a drop down from the list.

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Git Repository Structure

The Git repository should contain the manifest file. A sample Git repository structure is given below.

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Prerequisites

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Configure Service Principal

To access the AKS cluster, we need a Service Principal( Client ID and Client Key). Created a Service Principal and corresponding secret (e.g. aksudpatesp) You need to provide the relevant Role to the Service Principal, so that it can do necessary deployment and other relevant activities. For our tutorial we have provided Azure Kubernetes Service RBAC Write Role as shown below. Any other K8s Role or custom Azure AD Role is also acceptable as long as the Service Principal has relevant access (e.g. deploy/run/delete etc) to execute kubectl commands in target Kubernetes cluster.

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Configure kubeconfig File

A Kubeconfig is a YAML file with the details to connect to Kubernetes Cluster using certificate/secret tokens to authenticate the cluster. This is essential for Kubernetes Plugin to connect to target AKS cluster. Why Change in kubeconfig Normally with earlier version of kubectl, the structure of config file was as given below. Where access-token was regenerated every one hour based on refresh-token and kubectl command used the access-token to authenticate against the k8s cluster before executing any command. However with current version of kubectl one would get below warning message: WARNING: the azure auth plugin is deprecated in v1.22+, unavailable in v1.26+; use https://github.com/Azure/kubelogin instead.

• This is because kubectl currently supports various vendor specific login.
• The logic used by the Azure auth provider is embedded in the kubectl binary, which is why you can authenticate and connect to the cluster without having to install anything else.
• Going forward this approach is going to change. It’s not going to support vendor specific authentication protocols.
• The authentication plugins are being moved out of the kubectl binary into separate binaries, maintained by the Cloud providers and distributed independently.
• Ref:

https://github.com/kubernetes/kubernetes/pull/102181 https://aptakube.com/blog/how-to-use-azure-kubelogin

• To overcome this issue, all Cloud providers have extended the client-go credential plugin to have custom Cloud specific authentication methods.
• Kubelogin is a client-go credential plugin that implements Azure AD authentication. This is the direction for AKS.

How to Change in kubeconfig

• Execute below command to use azurecli as kubelogin option to retrieve access token. With this changes kubelogin will internally generate the token. No update required in kubeconfig file going forward.

kubelogin convert-kubeconfig -l azurecli

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CLI Installation

• Azure CLI should be installed in the m/c where the plugin is to be executed. Preferably add Azure CLI path in m/c classpath.
• Install/copy kubelogin on the system. Add kubelogin in m/c path variable.

ref: https://github.com/Azure/kubelogin/releases

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Build and Deploy Workflows

Navigate to Workflows and create a workflow using the :Create_Button: button as highlighted below. Create one Build and one Deploy workflow.

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Build Workflow

Below given is a sample build workflow to copy the file from a Git repository. Step-i: Clone Git Repository
This step will clone the Git repository codebase into the project execution working directory. The Git URL will be retrieved from Source Control configured under Project Configuration. Step-ii: Copy the manifest file
The below step will copy the manifest file to the artifact. Also check the Produces Artifact option to save the files as artifact so that can be used from Deploy workflow.

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Deploy Workflow

Below given is a sample deploy workflow to deploy an application on an AKS cluster. Step-i: deploy the application This step will deploy the Nginx application, using the manifest on the AKS cluster. Context must be provided to apply changes. The context should be present inside kubeconfig file.

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Project Configuration

Navigate to the Project tab and create a Project with a logical name(KubernetesAzure in this case) Configure the Build and Deploy workflow that has been created in previous steps as shown below.

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Source Control

Configure the Source SCM repository under Source Control as shown below.

1. To configure Project specific Source Control one first need to navigate to the Project Configuration tab.
2. Next, expand the SOURCE CONTROL option from the left-hand pane.
3. Select SOURCES for configuring the Source Repository
4. Select the appropriate Source Control Type
5. Configure Source Repository. For detailed steps of Source Control configuration please refer to Configure Source Control in FlexDeploy

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Target Properties

Select Topology from the menu and then select Targets. Select the target group and environment, provide the properties detail, according to the description.

Properties	Mandatory field	Description
Cloud Account	Optional	Select the Cloud Account to connect cluster.
CLI Path	Optional	Directory where Cloud CLI is installed.
Kubeconfig File Path	Optional	Absolute path of kubeconfig file
Kubernetes home path	Optional	Directory of Kubernetes home path(where kubectl is installed)
GIT Path	Optional	Path to the Git executable. Required only if Git is not on PATH.

Below given are the environment-specific values which need to be updated.

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Cloud Account

The Azure Cloud account needs to be set here from the drop-down. It will show all Cloud Accounts configured under Topology, which we have already mentioned earlier.

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Kubeconfig file path

Absolute path of config file can be set as environment property, if path is not set then by default plugin look for config file in user directory.

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CLI path

Azure CLI path can be set as environment property, if it’s not set then by default plugin will check for CLI in system classpath.

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Kubernetes Home Path

Kubernetes home path can be set as environment property, plugin check for kubectl on the given directory.

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Override properties at Project level

Let assume a scenario, where we want to change Cloud account for any specific project. Apart from setting at environment level, it can also be set at project properties by using Override Property. Please check below mentioned steps.

1. Navigate to the Project Configuration tab as shown above.
2. Next, select the PROPERTIES option from the left-hand pane.
3. Click on the OVERRIDE option.
4. Select the Cloud Account option from Property.
5. Select the Environment from the drop down list.
6. Select the Target Group from the drop down list.

We can do the same for other properties as well.

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Build Execution

For detailed steps on how to initiate deploy operation using Kubernetes plugin, please refer to Deploy through FlexDeploy for Kubernetes plugin

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Post deployment

Post deployment success from plugin it can take a little while for the deployment and running. Once deployment successfully completed, we can see the related details on AKS cluster by using Azure console. Congratulations! You have successfully completed the Nginx Application deployment. Now that you have configured FlexDeploy for deployment operation using Kubernetes plugin, it is extremely easy to replicate the same for other Cloud Provider. Simply use the Copy Project feature and a new project will be created with all of the configuration completed already. You just need to make the necessary configuration changes.