Install existing applications with Helm in Azure Kubernetes Service (AKS)

Článok
08/01/2024

Helm is an open-source packaging tool that helps you install and manage the lifecycle of Kubernetes applications. Similar to Linux package managers, such as APT and Yum, you can use Helm to manage Kubernetes charts, which are packages of preconfigured Kubernetes resources.

This article shows you how to configure and use Helm in a Kubernetes cluster on Azure Kubernetes Service (AKS).

Before you begin

This article assumes you have an existing AKS cluster. If you need an AKS cluster, create one using Azure CLI, Azure PowerShell, or Azure portal.
Your AKS cluster needs to have an integrated ACR. For details on creating an AKS cluster with an integrated ACR, see Authenticate with Azure Container Registry from Azure Kubernetes Service.
You also need the Helm CLI installed, which is the client that runs on your development system. It allows you to start, stop, and manage applications with Helm. If you use the Azure Cloud Shell, the Helm CLI is already installed. For installation instructions on your local platform, see Installing Helm.

Important

Helm is intended to run on Linux nodes. If you have Windows Server nodes in your cluster, you must ensure that Helm pods are only scheduled to run on Linux nodes. You also need to ensure that any Helm charts you install are also scheduled to run on the correct nodes. The commands in this article use node-selectors to make sure pods are scheduled to the correct nodes, but not all Helm charts may expose a node selector. You can also consider using other options on your cluster, such as taints.

Verify your version of Helm

Use the helm version command to verify you have Helm 3 installed.

helm version

The following example output shows Helm version 3.0.0 installed:

version.BuildInfo{Version:"v3.0.0", GitCommit:"e29ce2a54e96cd02ccfce88bee4f58bb6e2a28b6", GitTreeState:"clean", GoVersion:"go1.13.4"}

Install an application with Helm v3

Add Helm repositories

Add the ingress-nginx repository using the helm repo command.

helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx

Find Helm charts

Search for precreated Helm charts using the helm search command.

helm search repo ingress-nginx

The following condensed example output shows some of the Helm charts available for use:

NAME                            CHART VERSION   APP VERSION     DESCRIPTION                                       
ingress-nginx/ingress-nginx     4.7.0           1.8.0           Ingress controller for Kubernetes using NGINX a...

Update the list of charts using the helm repo update command.

helm repo update

The following example output shows a successful repo update:

Hang tight while we grab the latest from your chart repositories...
...Successfully got an update from the "ingress-nginx" chart repository
Update Complete. ⎈ Happy Helming!⎈

Import the Helm chart images into your ACR

This article uses the NGINX ingress controller Helm chart, which relies on three container images.

Use az acr import to import the NGINX ingress controller images into your ACR.

REGISTRY_NAME=<REGISTRY_NAME>
CONTROLLER_REGISTRY=registry.k8s.io
CONTROLLER_IMAGE=ingress-nginx/controller
CONTROLLER_TAG=v1.8.0
PATCH_REGISTRY=registry.k8s.io
PATCH_IMAGE=ingress-nginx/kube-webhook-certgen
PATCH_TAG=v20230407
DEFAULTBACKEND_REGISTRY=registry.k8s.io
DEFAULTBACKEND_IMAGE=defaultbackend-amd64
DEFAULTBACKEND_TAG=1.5

az acr import --name $REGISTRY_NAME --source $CONTROLLER_REGISTRY/$CONTROLLER_IMAGE:$CONTROLLER_TAG --image $CONTROLLER_IMAGE:$CONTROLLER_TAG
az acr import --name $REGISTRY_NAME --source $PATCH_REGISTRY/$PATCH_IMAGE:$PATCH_TAG --image $PATCH_IMAGE:$PATCH_TAG
az acr import --name $REGISTRY_NAME --source $DEFAULTBACKEND_REGISTRY/$DEFAULTBACKEND_IMAGE:$DEFAULTBACKEND_TAG --image $DEFAULTBACKEND_IMAGE:$DEFAULTBACKEND_TAG

Note

In addition to importing container images into your ACR, you can also import Helm charts into your ACR. For more information, see Push and pull Helm charts to an Azure container registry.

Run Helm charts

Install Helm charts using the helm install command and specify a release name and the name of the chart to install.

Tip

The following example creates a Kubernetes namespace for the ingress resources named ingress-basic and is intended to work within that namespace. Specify a namespace for your own environment as needed.

ACR_URL=<REGISTRY_URL>

# Create a namespace for your ingress resources
kubectl create namespace ingress-basic

# Use Helm to deploy an NGINX ingress controller
helm install ingress-nginx ingress-nginx/ingress-nginx \
    --version 4.0.13 \
    --namespace ingress-basic \
    --set controller.replicaCount=2 \
    --set controller.nodeSelector."kubernetes\.io/os"=linux \
    --set controller.image.registry=$ACR_URL \
    --set controller.image.image=$CONTROLLER_IMAGE \
    --set controller.image.tag=$CONTROLLER_TAG \
    --set controller.image.digest="" \
    --set controller.admissionWebhooks.patch.nodeSelector."kubernetes\.io/os"=linux \
    --set controller.service.annotations."service\.beta\.kubernetes\.io/azure-load-balancer-health-probe-request-path"=/healthz \
    --set controller.admissionWebhooks.patch.image.registry=$ACR_URL \
    --set controller.admissionWebhooks.patch.image.image=$PATCH_IMAGE \
    --set controller.admissionWebhooks.patch.image.tag=$PATCH_TAG \
    --set defaultBackend.nodeSelector."kubernetes\.io/os"=linux \
    --set defaultBackend.image.registry=$ACR_URL \
    --set defaultBackend.image.image=$DEFAULTBACKEND_IMAGE \
    --set defaultBackend.image.tag=$DEFAULTBACKEND_TAG \
    --set defaultBackend.image.digest=""

The following condensed example output shows the deployment status of the Kubernetes resources created by the Helm chart:

NAME: nginx-ingress
LAST DEPLOYED: Wed Jul 28 11:35:29 2021
NAMESPACE: ingress-basic
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
The ingress-nginx controller has been installed.
It may take a few minutes for the LoadBalancer IP to be available.
You can watch the status by running 'kubectl --namespace ingress-basic get services -o wide -w nginx-ingress-ingress-nginx-controller'
...

Get the EXTERNAL-IP of your service using the kubectl get services command.

kubectl --namespace ingress-basic get services -o wide -w ingress-nginx-ingress-nginx-controller

The following example output shows the EXTERNAL-IP for the ingress-nginx-ingress-nginx-controller service:

NAME                                     TYPE           CLUSTER-IP    EXTERNAL-IP     PORT(S)                      AGE   SELECTOR
nginx-ingress-ingress-nginx-controller   LoadBalancer   10.0.254.93   <EXTERNAL_IP>   80:30004/TCP,443:30348/TCP   61s   app.kubernetes.io/component=controller,app.kubernetes.io/instance=nginx-ingress,app.kubernetes.io/name=ingress-nginx

List releases

Get a list of releases installed on your cluster using the helm list command.

helm list --namespace ingress-basic

The following example output shows the ingress-nginx release deployed in the previous step:

NAME            NAMESPACE       REVISION        UPDATED                                 STATUS          CHART                   APP VERSION
ingress-nginx   ingress-basic   1               2021-07-28 11:35:29.9623734 -0500 CDT   deployed        ingress-nginx-3.34.0    0.47.0

Clean up resources

Deploying a Helm chart creates Kubernetes resources like pods, deployments, and services.

Clean up resources using the helm uninstall command and specify your release name.
```
helm uninstall --namespace ingress-basic ingress-nginx
```
The following example output shows the release named ingress-nginx has been uninstalled:
```
release "nginx-ingress" uninstalled
```
Delete the entire sample namespace along with the resources using the kubectl delete command and specify your namespace name.
```
kubectl delete namespace ingress-basic
```

Next steps

For more information about managing Kubernetes application deployments with Helm, see the Helm documentation.

Helm documentation

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