Models UI

Web app for managing Model servers

The Models web app is an abstraction that provides users a graphical UI to manage their Model servers, by performing CRUD operations on top of InferenceService CustomResources.

The web app is also exposing information from the underlying Knative resources, like Conditions from the Knative Configurations, Route and Revisions as well as live logs from the Model server pod.

Installation and Access

The web app’s manifests are part of the upstream KFServing manifests. This means that the necessary resources will be deployed when installing KFServing. KFServing manifests for the 0.6 release come with two flavors, standalone and kubeflow. The web app’s manifests are part of both installation options.

The web app includes the following resources:

  • A Deployment for running the backend server, and serving the static frontend files
  • A Service for configuring the incluster network traffic
  • A ServiceAccount and ClusterRole{Binding} to give the necessary permissions to the web app’s Pod
  • A VirtualService for exposing the app via the cluster’s Istio Ingress Gateway

Standalone

In this case all the resources of the web app will be installed in the kfserving-system namespace. Users can access the web app either via the knative-ingress-gateway.knative-serving Istio Ingress Gateway or by port-forwarding the backend.

Port forwarding

# set the following ENV vars in the app's Deployment
kubectl edit -n kfserving-system deployments.apps kfserving-models-web-app
# APP_PREFIX: /
# APP_DISABLE_AUTH: "True"
# APP_SECURE_COOKIES: "False"

# expose the app under localhost:5000
kubectl port-forward -n kfserving-system svc/kfserving-models-web-app 5000:80

Kubeflow

The web app is not part of the Kubeflow 1.3 release manifests. The web app was introduced in KFServing 0.6 and the Kubeflow manifests for 1.3 include KFServing 0.5.

The KFServing manifests include a kubeflow overlay, which you can apply in you cluster to launch the web app in a Kubeflow 1.3 installation. You can also add the following section to the Central Dashboard’s ConfigMap in order to add an entry for this web app:

{
  "link": "/models/",
  "text": "Models",
  "icon": "settings_ethernet"
},

Authorization

SubjectAccessReviews

The web app has a mechanism for performing authentication and authorization checks, to ensure that user actions are compliant with the cluster’s RBAC, which is only enabled in the kubeflow manifests of the app. This mechanism can be toggled by leveraging the APP_DISABLE_AUTH: "True" | "False" ENV Var.

This mechanism is only enabled in the kubeflow manifests since in a Kubeflow installation all requests that end up in the web app’s Pod will also contain a custom header that denotes the user. In a Kubeflow installation there’s an authentication component in front of the cluster that ensures only logged in users can access the cluster’s services. In the standalone mode such a component might not always be deployed.

The web app will be using the value from this custom header to extract the name of the K8s user that made the request. Then it will create a SubjectAccessReview to check if the user has permissions to perform the specific action, for example deleting an InferenceService in a namespace.

Namespace selection

Both in standalone and in kubeflow setups the user needs to be able to select a Namespace in order to interact with the InferenceServices in it.

In standalone mode the web app will show a dropdown that will show all the namespaces to the user and allow them to select any of them. The backend will make a LIST request to the API Server to get all the namespaces. In this case the only authorization check that takes place is in the K8s API Server that ensures the web app Pod’s ServiceAccount has permissions to list namespaces.

In kubeflow mode the Central Dashboard is responsible for the Namespace selection. Once the user selects a namespace then the Dashboard will inform the iframed Models web app about the newly selected namespace. The Models web app itself won’t expose a dropdown namespace selector in this mode.

Use Cases

Currently users can do the following workflows via this web app:

  • See a list of the existing InferenceService CRs in a Namespace
  • Create a new InferenceService by providing a YAML
  • Inspect an InferenceService
    • View the live status of the InferenceService
    • Inspect the K8s Conditions of the underlying Knative resources
    • View the logs of the created Model server Pod, for that InferenceService
    • Inspect the YAML contents as they are stored in the K8s API Server
    • View some basic metrics

Listing

The main page of the app provides a list of all the InferenceServices that are deployed in the selected Namespace. The frontend periodically polls the backend for the latest state of InferenceServices.

Models web app main page

Creating

The page for creating a new InferenceService. The user can paste the YAML object of the InferenceService they wish to create.

Note that the backend will override the provided .metadata.namespace field of the submitted object, to prevent users from trying to create InferenceServices in other namespaces.

Models web app create page

Deleting

Users can delete an existing InferenceService by clicking on the icon next to an InferenceService, in the main page that lists all the namespaced resources.

Inspecting

Users can click on the name of an InferenceService, from the main page, and view a more detailed summary of the CR’s state. In this page users can inspect:

  1. The overview of the InferenceService’s status (OVERVIEW)
  2. A user friendly representation of the CR’s spec (DETAILS)
  3. Metrics from the underlying resources (METRICS)
  4. Logs from the created Pods (LOGS)
  5. The YAML file as is in the K8s API Server (YAML)
Models web app overview page

Metrics

As mentioned in the above sections the web app allows users to inspect the metrics from the InferenceService. This tab will not be enable by default. In order to expose it the users will need to install Grafana and Prometheus.

Currently the frontend is expecting to find a Grafana exposed in the /grafana prefix. This Grafana instance will need to have specific dashboards in order for the app to embed them in iframes. We are working on making this more generic to allow people to expose their own graphs.

You can install Grafana and Prometheus, for the web app to consume, by installing

  1. the monitoring-core.yaml and monitoring-metrics-prometheus.yaml files from the Knative 0.18 release
  2. the following yaml files for exposing Grafana outside the cluster, by allowing anonymous access


apiVersion: v1
kind: ConfigMap
metadata:
  name: grafana-custom-config
  namespace: knative-monitoring
  labels:
    serving.knative.dev/release: "v0.11.0"
data:
  custom.ini: |
    # You can customize Grafana via changing the context of this field.
    [auth.anonymous]
    # enable anonymous access
    enabled = true
    [security]
    allow_embedding = true
    [server]
    root_url = "/grafana"
    serve_from_sub_path = true    


apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: grafana
  namespace: knative-monitoring
spec:
  gateways:
  - kubeflow/kubeflow-gateway
  hosts:
  - '*'
  http:
  - match:
    - uri:
        prefix: /grafana/
    route:
    - destination:
        host: grafana.knative-monitoring.svc.cluster.local
        port:
          number: 30802


apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
  name: models-web-app
  namespace: kubeflow
spec:
  action: ALLOW
  rules:
  - from:
    - source:
        principals:
        - cluster.local/ns/istio-system/sa/istio-ingressgateway-service-account
  selector:
    matchLabels:
      kustomize.component: kfserving-models-web-app
      app.kubernetes.io/component: kfserving-models-web-app

After applying these YAMLs, based on your installation mode, and ensuring the Grafana instance is exposed under /grafana the web app will show the METRICS tab.

Models web app metrics page

Configurations

The following is a list of ENV var that can configure different aspects of the application.

ENV Var Default value Description
APP_PREFIX “/models” Controls the app’s prefix, by setting the base-url element
APP_DISABLE_AUTH “False” Controls whether the app should use SubjectAccessReviews to ensure the user is authorized to perform an action
APP_SECURE_COOKIES “True” Controls whether the app should use Secure CSRF cookies. By default the app expects to be exposed with https
CSRF_SAMESITE “Strict” Controls the SameSite value of the CSRF cookie
USERID_HEADER “kubeflow-userid” Header in each request that will contain the username of the logged in user
USERID_PREFIX "" Prefix to remove from the USERID_HEADER value to extract the logged in user name

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Last modified August 20, 2021: Fix typos in docs (#2884) (e1639edb)