Container Compute Service:Schedule pods to ACS using virtual nodes

How virtual nodes provide ACS computing power

Container Compute Service (ACS) is a container service that uses Kubernetes as its user interface and provides computing resources that comply with container specifications. ACS uses a layered architecture that separates the Kubernetes control plane from the underlying container computing power. The ACS computing resource layer is responsible for scheduling and allocating resources for Pods, while Kubernetes manages application workloads such as Deployments, Services, StatefulSets, and CronJobs on top of this layer.

You can connect ACS container computing power to a Kubernetes cluster as a virtual node. This gives your cluster powerful elasticity, unconstrained by the computing capacity of its nodes. When ACS takes over the management of the underlying infrastructure for Pods, Kubernetes no longer needs to directly handle the placement and startup of individual Pods or monitor the resource status of underlying virtual machines. ACS ensures the required Pod resources are always available.

In an registered cluster, install the ack-virtual-node add-on from the Component Center to deploy virtual nodes and create ACS pods. When the cluster needs to scale out, create ACS pods on virtual nodes on demand, without planning the compute capacity of nodes. ACS pods can communicate over the network with the pods on the physical nodes of the cluster. For more information, see Registered clusters.

To use resources more efficiently, shorten scale-out times, and reduce costs, schedule long-running workloads whose traffic fluctuates elastically to virtual nodes. As traffic decreases, quickly release the pods on virtual nodes to reduce usage costs.

Pods on virtual nodes run in a secure, isolated container runtime environment on ACS. Each pod corresponds to one ACS instance.

Prerequisites

• You have created an registered cluster and connected it to a Kubernetes cluster in a data center or on another cloud provider. Kubernetes 1.24 or later is recommended. For more information, see Create an ACK One registered cluster.

• You have installed the ack-virtual-node component, version 2.13.0 or later. For more information, see Grant RAM permissions to the ack-virtual-node component and Install the ack-virtual-node component.

Example: use ACS CPU computing power

As of version 2.13.0 or later, the ack-virtual-node add-on provides both ACS and Elastic Container Instance (ECI) computing power.

To use ACS CPU computing power in an ACK One registered cluster, perform the following steps:

1. Create a file named nginx.yaml with the following content:

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: nginx
     labels:
       app: nginx
   spec:
     replicas: 2
     selector:
       matchLabels:
         app: nginx
     template:
       metadata:
         labels:
           app: nginx 
           alibabacloud.com/acs: "true" # Use ACS computing power.
           alibabacloud.com/compute-class: general-purpose # The compute class of the ACS pod. Default value: general-purpose.
           alibabacloud.com/compute-qos: default # The QoS class of the ACS pod. Default value: default.
       spec:
         containers:
         - name: nginx
           image: mirrors-ssl.aliyuncs.com/nginx:stable-alpine
           ports:
             - containerPort: 80
               protocol: TCP 
           resources:
             limits:
               cpu: 2
             requests:
               cpu: 2

2. Run the following command to create the NGINX application.

   kubectl apply -f nginx.yaml

3. Run the following command to check the pod status.

   kubectl get pods -o wide

   Expected output:

   NAME                     READY   STATUS    RESTARTS   AGE     IP               NODE                            NOMINATED NODE   READINESS GATES
   nginx-54bcbc9b66-****   1/1     Running   0          3m29s   192.168.XX.XXX   virtual-kubelet-cn-shanghai-l   <none>           <none>
   nginx-54bcbc9b66-****   1/1     Running   0          3m29s   192.168.XX.XXX   virtual-kubelet-cn-shanghai-l   <none>           <none>

   These two Pods are scheduled to nodes labeled type=virtual-kubelet through nodeSelector.

4. Run the following command to view the details of the NGINX pod.

   kubectl describe pod nginx-54bcbc9b66-****

   Expected output:

   Annotations:  ProviderCreate: done
                 alibabacloud.com/instance-id: acs-uf6008giwgjxlvn*****
                 alibabacloud.com/pod-ephemeral-storage: 30Gi
                 alibabacloud.com/pod-use-spec: 2-2Gi
                 kubernetes.io/pod-stream-port: 10250
                 network.alibabacloud.com/enable-dns-cache: false
                 topology.kubernetes.io/region: cn-shanghai

   The alibabacloud.com/instance-id: acs-uf6008giwgjxlvn***** annotation in the output confirms that the pod is an ACS pod.

Example: use ACS GPU computing power

The process for using ACS GPU computing power is similar to that for ACS CPU computing power, but it requires specific component versions and some additional configuration.

ACS GPU computing power in an registered cluster is in invitational preview. To apply for access, submit a ticket.

...     
     labels:
        # Declare the ACS GPU resource requirement in the labels.
        alibabacloud.com/compute-class: gpu     # For GPU types, use the fixed value 'gpu'.
        alibabacloud.com/compute-qos: default   # The QoS class. This has the same meaning as for regular ACS computing power.
        alibabacloud.com/gpu-model-series: example-model  # The GPU model series. Replace with your actual model, such as T4.
...