tencent cloud

How do I prohibit a Pod from being scheduled to a pay-as-you-go supernodes?

By default, an ordinary TKE cluster will automatically schedule a Pod to a pay-as-you-go supernodes after a node pool of the pay-as-you-go supernodes type is added to it when node resources are insufficient. An serverless cluster will automatically schedule Pod randomly at multiple pay-as-you-go supernodes.

If you do not want to schedule a Pod to some pay-as-you-go supernodes (which represents a certain subnet/availability zone), you can cordon the pay-as-you-go supernodes in the following two ways:

• Cordon nodes via the TKE console. For more information, see Cordoning a Node.
• Prohibit scheduling by executing the following command through the command line:

  $kubectl cordon $pay-as-you-go supernodes name
  

How do I prohibit ordinary TKE clusters from automatically scheduling a Pod to a pay-as-you-go supernodes in case of resource inadequacy?

You need to create a configmap called “eks-config” in the kube-system namespace by running the following command:

$kubectl create configmap eks-config --from-literal=AUTO_SCALE_EKS=false

Specify the value of AUTO_SCALE_EKS as false, and you can disable the automatic scheduling mechanism to prohibit ordinary TKE clusters from automatically scheduling a Pod to a pay-as-you-go supernodes.

How do I manually schedule a Pod to a pay-as-you-go supernodes?

By default, a pay-as-you-go supernodes automatically adds taints to lower the scheduling priority. If you want to manually schedule a Pod to a (specified) pay-as-you-go supernodes, you need to add corresponding tolerations for the Pod. However, not all the Pods can be scheduled to pay-as-you-go supernodes. For more information, see Notes for Scheduling Pod to Supernodes. For the sake of convenience, you can specify nodeselector in Pod Spec, as shown below；

spec:    
    nodeSelector:
      node.kubernetes.io/instance-type: eklet

TKE’s control components will judge whether the Pod can be scheduled to a pay-as-you-go supernodes. If not, the Pod will not be scheduled to the pay-as-you-go supernodes.

How do I forcibly schedule a Pod to a pay-as-you-go supernodes, no matter whether the pay-as-you-go supernodes supports the Pod?

Note：

If you forcibly schedule a Pod to a pay-as-you-go supernodes, the Pod may fail to be created. For information on the cause of he failure, see How do I manually schedule a Pod to a pay-as-you-go supernodes?.

If you need to forcibly schedule a Pod to a pay-as-you-go supernodes, you not only need to specify nodeselector or nodename for the Pod but also add corresponding tolerations.

1. Specify nodeselector in Pod Spec, as shown below:

    spec:    
      nodeSelector:
        node.kubernetes.io/instance-type: eklet
   

   Or specify nodename in Pod Spec, as shown below:

   spec: 
      nodeName: $pay-as-you-go supernodes name
   

2. Add tolerations for the Pod, as shown below:

   spec: 
      tolerations: 
      - effect: NoSchedule
        key: eks.tke.cloud.tencent.com/eklet
        operator: Exists
   

How do I customize DNS configuration for a pay-as-you-go supernodes?

Serverless cluster supports pay-as-you-go supernodes. You can specify annotations in a YAML file to implement capabilities such as custom DNS. For more information, see Pay-as-you-go Supernodes Annotation Description.