Use Helm to simplify application deployment

Introduction to Helm

Helm is an open source tool that is used to manage applications in Kubernetes clusters. Helm provides a unified method to package software and manage software versions. You can use Helm to simplify the deployment and management of Kubernetes applications. The following table describes the basic concepts of Helm. For more information, see Helm.

Prerequisites

• An ACK cluster is created. For more information, see Create an ACK managed cluster.

• Connect to the cluster by using kubectl, and the Helm CLI is installed. For more information, see Obtain the kubeconfig file of a cluster and use kubectl to connect to the cluster and Installing Helm.

Deploy an application in the ACK console

ACK provides charts of some common applications. You can use the charts to install applications in the console. The following steps describe how to install WordPress by using Helm.

1. Log on to the ACK console. In the left-side navigation pane, click Clusters.

2. On the Clusters page, find the cluster that you want to manage and click its name. In the left-side pane, choose Applications > Helm.

3. On the Helm page, click Deploy. In the Basic Information step, configure the parameters based on the following table.

   Parameter	Description	Example

   Parameter	Description	Example
   Application Name	The name of the release in the cluster.	wordpress
   Namespace	The namespace in which the release is deployed.	default
   Source	The source of charts. Marketplace or ACR EE can be selected.	Marketplace
   Chart	The chart used to install the application.	ack-wordpress-sample

4. Click Next in the lower-left corner of the panel and select the latest chart version. Confirm the chart content and click OK in the lower part of the panel.

5. After WordPress is installed, run the following command to obtain the external IP address (EXTERNAL-IP ):

   kubectl get svc --namespace default 

   The expected output indicates that the EXTERNAL-IP is 118.xx.xx. 10.

   NAME                                TYPE           CLUSTER-IP      EXTERNAL-IP      PORT(S)                      AGE
   wordpressabc-ack-wordpress-sample   LoadBalancer   172.16.86.22    118.190.xx.xx   80:30837/TCP,443:32433/TCP   33m
   wordpressabc-mariadb                ClusterIP      172.16.70.108   <none>           3306/TCP                     33m

6. Run the kubectl get pod command to obtain the name of the WordPress pod, and then run the following command to obtain the access user:

   kubectl get pod <wordpress-ack-wordpress-sample-name> -o=jsonpath='{.spec.containers[*].env[?(@.name=="WORDPRESS_USERNAME")].value}'

   Expected output:

   user

7. Run the following command to obtain the password:

   kubectl get secret --namespace default wordpress-ack-wordpress-sample -o jsonpath="{.data.wordpress-password}" | base64 --decode

   Expected output:

   ps**jRx**V

8. In a browser, enter the EXTERNAL-IP that you obtained in the previous step, add /login after the IP to access the WordPress application, and then enter the user and password on the login page.

   

Manage the installed applications in the console

You can perform operations on the installed release on the Helm page.

• Click Release Name or View Details to view information about the release, such as resources, YAML files, and history versions.

• Click Update. In the Update Release panel, modify the parameters based on your requirements and click OK to update the release.

• Click Delete. In the Delete dialog box, select Clear Release Records and click OK. After the release is deleted, the resources of the release are deleted, including the Services and Deployments.

  Important

  If you clear Clear Release Records, the release is not deleted. The release remains in the release list. If you create another release that has the same name, a release name conflict occurs. As a result, applications that have the same name as the release fail to be deployed.

Use a third-party chart repository to deploy applications by using the Helm CLI

If the charts provided by ACK cannot meet your requirements, you can use third-party charts to deploy applications by using the Helm CLI.

helm repo add <REPO_NAME> <REPO_URL> # Add a chart repository. Replace REPO_NAME with the name of the chart repository. Replace REPO_URL with the address of the chart repository.
helm repo update # Update repository information.
helm install <APP_NAME> <REPO_NAME>/<CHART_NAME> # Install the application. Replace APP_NAME with the name of an application and CHART_NAME with the name of a chart.

For more information about Helm commands, see Using Helm.

References

• To prevent the potential security risks imposed by the Helm V2 server Tiller, we recommend that you update Helm V2 to Helm V3 to use more Helm features. Otherwise, attackers may use Tiller to install unauthorized applications in your cluster. You can run the following command to view the Helm version in the cluster: For more information about the update operations, see Update Helm V2 to Helm V3.

  helm version

  Expected output:

  version.BuildInfo{Version:"***", GitCommit:"***", GitTreeState:"***", GoVersion:"go***"}

• You can use the Helm chart feature of the Container Registry Enterprise Edition instance to pull and push charts. For more information, see Push and pull Helm charts.