Container Service for Kubernetes:Enable CPU QoS for containers

Step 1: Apply the ConfigMap

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

   To apply CPU QoS to a workload such as a Deployment, add the koordinator.sh/qosClass label to the Pod template under template.metadata.

   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: ack-slo-config
     namespace: kube-system
   data:
     # Enable the CPU QoS feature for containers.
     resource-qos-config: |
       {
         "clusterStrategy": {
           "lsClass": {
             "cpuQOS": {
               "enable": true,
               "groupIdentity": 2
             }
           },
           "beClass": {
             "cpuQOS": {
               "enable": true,
               "groupIdentity": -1
             }
           }
         }
       }

   lsClass configures LS Pods; beClass configures BE Pods. Key cpuQOS parameters:

   Parameter	Type	Valid values	Description
   enable	Boolean	true / false	true: enables CPU QoS cluster-wide. false: disables it.
   groupIdentity	Integer	-1 to 2	The kernel scheduling priority for the cgroup. Higher values mean higher priority. Default: 2 for LS Pods, -1 for BE Pods. Set to 0 to disable group identity for that class.

2. Check if the ack-slo-config ConfigMap exists in the kube-system namespace:

   • If it exists, patch it to preserve other configuration fields:

     kubectl patch cm -n kube-system ack-slo-config --patch "$(cat configmap.yaml)"

   • If it does not exist, create it:

     kubectl apply -f configmap.yaml

Step 2: Deploy an LS Pod and verify

1. Create a file named ls-pod-demo.yaml with the following content:

   apiVersion: v1
   kind: Pod
   metadata:
     name: ls-pod-demo
     labels:
       koordinator.sh/qosClass: 'LS' # Specify the QoS class of the Pod as LS.
   spec:
     containers:
     - command:
       - httpd
       - -D
       - FOREGROUND
       image: registry.cn-zhangjiakou.aliyuncs.com/acs/apache-2-4-51-for-slo-test:v0.1
       imagePullPolicy: Always
       name: apache
       resources:
         limits:
           cpu: "4"
           memory: 10Gi
         requests:
           cpu: "4"
           memory: 10Gi
     restartPolicy: Never
     schedulerName: default-scheduler

2. Deploy the Pod:

   kubectl apply -f ls-pod-demo.yaml

3. On the node, check the group identity assigned to the LS Pod's cgroup:

   cat /sys/fs/cgroup/cpu/kubepods.slice/kubepods-pod1c20f2ad****.slice/cpu.bvt_warp_ns

   Expected output:

   # The group identity of the LS Pod is 2, which indicates high priority.
   2

Step 3: Deploy a BE Pod and verify

1. Create a file named be-pod-demo.yaml with the following content:

   apiVersion: v1
   kind: Pod
   metadata:
     name: be-pod-demo
     labels:
       koordinator.sh/qosClass: 'BE' # Specify the QoS class of the Pod as BE.
   spec:
     containers:
       - args:
           - '-c'
           - '1'
           - '--vm'
           - '1'
         command:
           - stress
         image: registry-cn-beijing.ack.aliyuncs.com/acs/stress:v1.0.4
         imagePullPolicy: Always
         name: stress
     restartPolicy: Always
     schedulerName: default-scheduler

2. Deploy the Pod:

   kubectl apply -f be-pod-demo.yaml

3. On the node, check the group identity assigned to the BE Pod's cgroup:

   cat /sys/fs/cgroup/cpu/kubepods.slice/kubepods-besteffort.slice/kubepods-besteffort-pod4b6e96c8****.slice/cpu.bvt_warp_ns

   Expected output:

   # The group identity of the BE Pod is -1, which indicates low priority.
   -1

The LS Pod's group identity is 2 and the BE Pod's is -1, confirming CPU QoS is active and the kernel prioritizes LS over BE workloads.

Protocol compatibility when upgrading to ack-koordinator

ack-slo-manager v0.8.0 and earlier used the alibabacloud.com/qosClass annotation for CPU QoS. ack-koordinator supports both protocols for incremental migration to koordinator.sh. Support for alibabacloud.com ended July 30, 2023—migrate to the new protocol.