Using Dynamic MPAM Isolation

You can use the dynamic MPAM isolation function to adjust the resource usage of some offline services.

(Optional) Configuring Dynamic MPAM Isolation Parameters

The plugin provides default configurations. Dynamic MPAM isolation can be used without configuring configMaps. Dynamic MPAM isolation parameters are configured in a JSON file. For details about the parameters, see Table 1. To manually change the configurations, refer to the following content.

 {
      "mpamConfig":{
        "adjustInterval": 5000,
        "perfDuration": 3000,
        "l3Percent": {
          "low": 20,
          "high": 50
        },
        "memBandPercent": {
          "low": 10,
          "high": 50
        },
        "cacheMiss": {
          "minMiss": 10,
          "maxMiss": 50
        }
      }
    }

**Table 1** Dynamic MPAM isolation parameters
Parameter	Description
adjustInterval	Interval between dynamic adjustments. For example, if this parameter is set to 1000, dynamic adjustment is performed every second.
perfDuration	Perf collection duration. For example, if this parameter is set to 1000, perf will collect data within one second each time.
l3Percent	Maximum and minimum L3 cache percentages that can be used by offline services during dynamic adjustment. For example, if low is set to 20 and high is set to 50, offline services can use at least 20% and at most 50% of L3 CacheWay during dynamic adjustment.
memBandPercent	Maximum and minimum memory bandwidth percentages that can be used by offline services during dynamic adjustment. For example, if low is set to 10 and high is set to 50, offline services can use at least 10% and at most 50% of the memory bandwidth during dynamic adjustment.
cacheMiss	Basis for determining whether to perform dynamic adjustment. For example, if minMiss is set to 10 and maxMiss is set to 50, the available resources of offline services are reduced when the cache miss rate of online services is greater than 50%, and are increased when the cache miss rate of online services is less than 10%.

A JSON file is configured in the form of configMap in the k8s-mpam-controller.yaml file. The complete YAML file is as follows:

apiVersion: v1
kind: ServiceAccount
metadata:
  name: mpam-controller-agent
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: mpam-controller-agent
rules:
- apiGroups:
  - ""
  resources:
  - configmaps
  - pods
  verbs:
  - get
  - list
  - watch
- apiGroups:
  - ""
  resources:
  - nodes
  verbs:
  - get
  - list
  - patch
  - update
  - watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: mpam-controller-agent
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: mpam-controller-agent
subjects:
- kind: ServiceAccount
  name: mpam-controller-agent
  namespace: default
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: mpam-config
data:
  config.json: |
    {
      "mpamConfig":{
        "adjustInterval": 10000,
        "perfDuration": 3000,
        "l3Percent": {
          "low": 20,
          "high": 50
        },
        "memBandPercent": {
          "low": 10,
          "high": 50
        },
        "cacheMiss": {
          "minMiss": 10,
          "maxMiss": 30
        }
      }
    }
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: mpam-controller-daemonset-agent
spec:
  selector:
    matchLabels:
      app: k8s-mpam-controller-agent
  template:
    metadata:
      labels:
        app: k8s-mpam-controller-agent
    spec:
      serviceAccountName: mpam-controller-agent
      hostPID: true
      hostIPC: true
      containers:
      - name: k8s-mpam-controller-agent
        image: k8s-mpam-controller:0.1
        securityContext:
          privileged: true
        command: ["/usr/bin/agent"]
        args: ["-direct"]
        resources:
          limits:
            memory: 200Mi
          requests:
            cpu: 100m
            memory: 200Mi
        env:
        - name: NODE_NAME
          valueFrom:
            fieldRef:
              apiVersion: v1
              fieldPath: spec.nodeName
        volumeMounts:
        - name: resctrl
          mountPath: /sys/fs/resctrl/
        - name: hostname
          mountPath: /etc/hostname
        - name: sysfs
          mountPath: /sys/fs/cgroup/
        - name: config-volume
          mountPath: /var/lib/mpam-config
      volumes:
      - name: resctrl
        hostPath:
          path: /sys/fs/resctrl/
      - name: hostname
        hostPath:
          path: /etc/hostname
      - name: sysfs
        hostPath:
          path: /sys/fs/cgroup/
      - name: config-volume
        configMap:
          name: mpam-config
          items:
            - key: config.json
              path: config.json

After the dynamic MPAM isolation function is enabled, the plugin creates the mpam-controller_dynamic directory in the /sys/fs/resctrl directory, as shown in the following figure.

Deploying Offline Services

Add the annotation kunpeng.com/offline: "true" to the YAML file of the Pod to label the Pod as an offline service so that the plugin can restrict the Pod. The following is a bw-mem.yaml file example.

apiVersion: v1
kind: Pod
metadata:
  name: bw-mem
  annotations:
    kunpeng.com/offline: "true"
spec:
  containers:
  - name: bw-mem
    image: bw-mem:latest
    imagePullPolicy: IfNotPresent
    command: [ "/bin/sh", "-c", "--" ]
    args: [ "while true; do sleep 300000; done;" ]
    securityContext:
      capabilities:
        add: ["ALL"]
    resources:
      requests:
        cpu: "9.6"
      limits:
        cpu: "9.6"

Deploy the offline service to be restricted.
```
kubectl apply -f bw-mem.yaml
```
After the deployment is successful, the PID of the offline service is added to tasks in the mpam-controller_dynamic control group.
Run the following commands to check PIDs of restricted offline services:
```
cd /sys/fs/resctrl/mpam-controller_dynamic
cat tasks
```

Parent topic: Virtualization MPAM Plugin User Guide