Load configuration from files instead of ConfigMaps

[AndersBennedsgaard]

/kind feature

Why you need this feature:

The actual centraldashboard-config ConfigMap is read every time a user interacts with the central dashboard. This puts unnecessary load on the Kubernetes API server, and increases latency for the dashboard.

Describe the solution you'd like:

I propose that the configuration is read from files mounted with the ConfigMap instead, using simple Pod volumes and volume mounts. The resulting Deployment would look something like:

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: centraldashboard
  name: centraldashboard
spec:
  replicas: 1
  selector:
    matchLabels:
      app: centraldashboard
  template:
    metadata:
      labels:
        app: centraldashboard
      annotations:
        sidecar.istio.io/inject: "true"
    spec:
      containers:
        - name: centraldashboard
          image: docker.io/kubeflownotebookswg/centraldashboard
          imagePullPolicy: IfNotPresent
          livenessProbe:
            httpGet:
              path: /healthz
              port: 8082
            initialDelaySeconds: 30
            periodSeconds: 30
          ports:
            - containerPort: 8082
              protocol: TCP
          env:
            - name: USERID_HEADER
              value: CD_USERID_HEADER_PLACEHOLDER
            - name: USERID_PREFIX
              value: CD_USERID_PREFIX_PLACEHOLDER
            - name: PROFILES_KFAM_SERVICE_HOST
              value: profiles-kfam.kubeflow
            - name: REGISTRATION_FLOW
              value: CD_REGISTRATION_FLOW_PLACEHOLDER
            - name: LOGOUT_URL
              value: "/authservice/logout"
            - name: POD_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
          volumeMounts:
            - name: centraldashboard-config
              mountPath: /etc/centraldashboard # can be changed
      volumes:
        - name: centraldashboard-config
          configMap:
            name: centraldashboard-config
      serviceAccountName: centraldashboard

(adapted from https://github.com/kubeflow/kubeflow/blob/master/components/centraldashboard/manifests/base/deployment.yaml)

Instead of calling the KubeAPI server on every GET, the dashboard would just have to parse files mounted somewhere in the container.
It would also be possible to get dynamic updates to the dashboard, since files mounted in this way are dynamically updated in the container, so we don't need to restart the deployment on config change.

Related lines of code:

kubeflow/components/centraldashboard/app/api.ts

Lines 82 to 111 in bd7f250

	.get(
	'/dashboard-links',
	async (_: Request, res: Response) => {
	const cm = await this.k8sService.getConfigMap();
	let links = {};
	try {
	links=JSON.parse(cm.data["links"]);
	}catch(e){
	return apiError({
	res, code: 500,
	error: ERRORS.invalid_links_config,
	});
	}
	res.json(links);
	})
	.get(
	'/dashboard-settings',
	async (_: Request, res: Response) => {
	const cm = await this.k8sService.getConfigMap();
	let settings = {};
	try {
	settings=JSON.parse(cm.data["settings"]);
	}catch(e){
	return apiError({
	res, code: 500,
	error: ERRORS.invalid_settings,
	});
	}
	res.json(settings);
	});

kubeflow/components/centraldashboard-angular/backend/app/api.ts

Lines 72 to 101 in bd7f250

	.get(
	'/dashboard-links',
	async (_: Request, res: Response) => {
	const cm = await this.k8sService.getConfigMap();
	let links = {};
	try {
	links=JSON.parse(cm.data["links"]);
	}catch(e){
	return apiError({
	res, code: 500,
	error: ERRORS.invalid_links_config,
	});
	}
	res.json(links);
	})
	.get(
	'/dashboard-settings',
	async (_: Request, res: Response) => {
	const cm = await this.k8sService.getConfigMap();
	let settings = {};
	try {
	settings=JSON.parse(cm.data["settings"]);
	}catch(e){
	return apiError({
	res, code: 500,
	error: ERRORS.invalid_settings,
	});
	}
	res.json(settings);
	});