Deploy the virtual node controller and use it to create Elastic Container Instance-based pods - User Guide for Kubernetes Clusters| Alibaba Cloud Documentation Center

Virtual nodes enable seamless integration between Kubernetes and Elastic Container Instance. Virtual nodes empower Kubernetes clusters with high elasticity. This way, Kubernetes clusters are no longer limited by the computing capacity of cluster nodes. You can create Elastic Container Instance-based pods as needed to avoid the planning of cluster capacity. This topic describes virtual nodes and elastic container instances. It also describes how to deploy the virtual node controller (ack-virtual-node) and use it to create Elastic Container Instance-based pods.

Prerequisites

A managed Kubernetes cluster or a dedicated Kubernetes cluster that uses a Kubernetes version later than 1.14 is created. For more information, see Create a managed Kubernetes cluster or Create a dedicated Kubernetes cluster.
Elastic Container Instance is activated. You can log on to the Elastic Container Instance console to activate the service.
The region where the cluster is deployed is supported by Elastic Container Instance. To view the supported regions and zones, log on to the Elastic Container Instance console.

Virtual nodes and elastic container instances

Elastic Container Instance is a serverless compute service that is provided by Alibaba Cloud for containerization. You can use elastic container instances to set up an O&M-free and isolated runtime environment for your containers. Elastic container instances allow you to focus on containerized applications without the need to purchase or manage Elastic Compute Service (ECS) instances. This way, you do not need to perform infrastructure maintenance. You can create elastic container instances to meet your business requirements. You are charged for resource usage on a per second basis.

Virtual nodes can drastically reduce computing costs and improve scaling efficiency. Virtual nodes are suitable in the following scenarios:

Online business that requires elastic scaling to withstand traffic fluctuations, such as online education and e-commerce. Virtual nodes optimize the maintenance of resource pools. This helps you reduce computing costs.
Virtual nodes can reduce costs in computing scenarios where Spark or Presto is used to process data.
Continuous integration and continuous delivery (CI/CD) pipeline: Jenkins and GitLab Runner.
Jobs: Jobs in AI computing scenarios and CronJobs.

Container Service for Kubernetes (ACK) provides multiple serverless container services based on virtual nodes and elastic container instances. These services include serverless Kubernetes (ASK) and ACK on Elastic Container Instance. You can use these services to deploy elastic and maintenance-free workloads.

Step 1: Deploy ack-virtual-node in ACK clusters

Note

The virtual node controller ack-virtual-node is managed by ASK clusters. Therefore, you can create Elastic Container Instance-based pods in ASK clusters without the need to deploy ack-virtual-node. In managed or dedicated Kubernetes clusters, you must deploy ack-virtual-node before you can create Elastic Container Instance-based pods.
In managed Kubernetes clusters, you can deploy ack-virtual-node on the Add-ons page of the console. By default, ack-virtual-node is managed by the clusters after it is deployed.
In dedicated Kubernetes clusters, you can deploy ack-virtual-node on the App Catalog page of the console. By default, ack-virtual-node is managed by the clusters after it is deployed.

Managed Kubernetes clusters

Perform the following steps to deploy ack-virtual-node in a managed Kubernetes cluster:

Log on to the ACK console.
In the left-side navigation pane of the ACK console, click Clusters.
On the Clusters page, find the cluster that you want to manage and click the name of the cluster or click Details in the Actions column. The details page of the cluster appears.
In the left-side navigation pane of the details page, choose Operations > Add-ons.
On the Add-ons page, select ack-virtual-node and click Install.
The default vSwitch and security group of the cluster are used for elastic container instances that are deployed by ack-virtual-node. If you want to modify these settings, see What to do next.

Dedicated Kubernetes Clusters

Perform the following steps to deploy ack-virtual-node in a dedicated Kubernetes cluster.

Log on to the ACK console.
In the left-side navigation pane of the ACK console, choose Marketplace > App Catalog.
On the App Catalog page, click the Alibaba Cloud Apps tab, and find and click ack-virtual-node.
A large number of applications are displayed on the Alibaba Cloud Apps tab. In the upper-left corner of the App Catalog page, you can enter ack-virtual-node in the Name search box and click the search icon to search for the application. You can also enter a keyword to perform a fuzzy match.
On the App Catalog - ack-virtual-node page, select the cluster where you want to deploy ack-virtual-node in the Deploy section.
Namespace is automatically set to kube-system. Release Name is automatically set to ack-virtual-node.

On the App Catalog - ack-virtual-node page, click the Parameters tab and set the parameters.


Parameter	Description	How to obtain the value
ALIYUN_CLUSTERID	The ID of the cluster where you want to deploy ack-virtual-node	Go to the details page of the cluster. Click the Basic Information tab. In the Basic Information section, you can view the cluster ID.
ALIYUN_RESOURCEGROUP_ID	The ID of the resource group to which the cluster belongs	If you do not specify this parameter, the default resource group is used. To specify a resource group, log on to the Resource Management console to obtain the ID of the resource group that you want to use.
ECI_REGION	The name of the region where the cluster is deployed	Go to the details page of the cluster. Click the Basic Information tab. In the Basic Information section, you can view the region where the cluster is deployed. Note For example, cn-hangzhou indicates the China (Hangzhou) region.
ECI_VSWITCH	vSwitches	On the Nodes page, click the ID of a node. On the instance details page, you can obtain the value of VSwtich in the Configuration Information section. Note Make sure that the zone of the vSwitch is supported by Elastic Container Instance. You can specify vSwitches that are deployed in different zones. Multiple vSwitches can be specified in the following format: `ECI_VSWITCH: "vsw-xxxxxxx1, vsw-xxxxxxx2, vsw-xxxxxxx3"`.
ECI_SECURITY_GROUP	The ID of the security group to which nodes in the cluster belong	On the Nodes page, click the ID of a node. On the instance details page, click the Security Groups tab. Then, click the Security Groups tab to obtain the security group ID.
ECI_ACCESS_KEY	The AccessKey ID of your account	For more information, see Obtain an AccessKey pair. You must attach the AliyunECIFullAccess policy to your account in the Resource Access Management (RAM) console. For more information, see Grant permissions to a RAM user.
ECI_SECRET_KEY	The AccessKey secret of your account	For more information, see Obtain an AccessKey pair. You must attach the AliyunECIFullAccess policy to your account in the RAM console. For more information, see Grant permissions to a RAM user.

On the App Catalog - ack-virtual-node page, select the cluster where you want to deploy ack-virtual-node in the Deploy section.
Namespace is automatically set to kube-system. Release Name is automatically set to ack-virtual-node. Click Create.
Check the deployment status of virtual-node-controller.
For more information, see Use kubectl on Cloud Shell to manage ACK clusters.
Run the following command to query the deployment status of virtual-node-controller:
```
kubectl -n kube-system get deploy ack-virtual-node-controller
```
Expected output:
```
NAME                     READY   AGE
virtual-node-controller  1/1     1m
```

Step 2: Create Elastic Container Instance-based pods

Note All pods in ASK clusters are deployed on elastic container instances. You do not need to use labels to identify these pods. Therefore, the following operations do not apply to ASK clusters. The following operations show how to create an Elastic Container Instance-based pod in an ACK cluster.

You can use the following methods to create an Elastic Container Instance-based pod in an ACK cluster.

Add a label to the pod.
Add the alibabacloud.com/eci=true label to the pod that you want to create. Then, an Elastic Container Instance-based pod is created and scheduled to a virtual node. Examples:
1. Run the following command to add a label to the pod:
```
kubectl run nginx --image nginx -l alibabacloud.com/eci=true
```
2. Run the following command to query the pod:
```
kubectl get pod -o wide|grep virtual-kubelet
```
  Expected output:
```
nginx-7fc9f746b6-r4xgx     0/1     ContainerCreating   0          20s   192.168.XX.XX   virtual-kubelet        <none>           <none>
```
Add a label to the namespace to which the pod belongs.
Add the alibabacloud.com/eci=true label to the namespace to which the pod belongs. Then, an Elastic Container Instance-based pod is created and scheduled to a virtual node. Example:
1. Run the following command to create a virtual node:
```
kubectl create ns vk
```
2. Run the following command to add a label to the namespace to which the pod belongs:
```
kubectl label namespace vk alibabacloud.com/eci=true
```
3. Run the following command to schedule the pod to a virtual node:
```
kubectl -n vk run nginx --image nginx
```
4. Run the following command to query the pod:
```
kubectl -n vk get pod -o wide|grep virtual-kubelet
```
  Expected output:
```
nginx-6f489b847d-vgj4d      1/1     Running             0          1m   192.168.XX.XX   virtual-kubelet        <none>           <none>
```

What to do next

Note The following operations apply only to ACK clusters and do not apply to ASK clusters.

Delete virtual nodes in ACK clusters

Uninstall ack-virtual-node.
- After you delete all Elastic Container Instance-based pods in a managed Kubernetes cluster, uninstall ack-virtual-node on the Add-ons page.
- After you delete all Elastic Container Instance-based pods in a dedicated Kubernetes cluster, delete ack-virtual-node on the Helm page.
Run the kubectl delete node <node name> to delete the virtual nodes that you want to delete.

Note If you do not delete the Elastic Container Instance-based pods in the cluster before you uninstall ack-virtual-node, the elastic container instances are retained in the cluster.