We're all handymen... but as geeks, we cannot stand transforming this into a side project...

This demonstration use the power of event-driven architecture and Knative serverless features to build an on-demand infrastructure for producing photo-realistic rendering of Blender scenes.

The architecture is summarized in below drawing:

• An ordering component is taking care of displaying a workbench UI, upload Blender files, propose and order rendering with different quality levels,
• Then, rendering requests are produced and published over a Kafka broker,
• A Knative source then spawns different rendering component pods that takes care of their own rendering tile of the whole scene,
• Rendered tile PNG are sent back through Kafka and the odering pod takes care of sending them back to the UI using WebSocket.

This demonstration has been created on OpenShift version 4.7 and recently updated to OpenShift 4.9+. If you stick with OpenShift 4.7 for now, check the manifests placed in /manifests/openshift-4.7 folder for specific resources versions.

This demonstration has been tested on OpenShift version 4.9. In order to deploy it, you'll need the AMQ Streams/Strimzi.io operator as well as the OpenShoft Serverless/Knative operator. Start installing these operators for the whole cluster:

oc create -f manifests/amq-streams-og.yml
oc create -f manifests/openshift-serverless-og.yml

oc create -f manifests/amq-streams-operator-subscription.yml
oc create -f manifests/serverless-operator-subscription.yml

Wait until knative-serving and knative-eventing projects are created after operators installation and then install the serverless infrastructure, enabling Knative serving, Knative eventing as well as Kafka event source addition:

oc create -f manifests/knative-serving.yml -n knative-serving
oc create -f manifests/knative-eventing.yml -n knative-eventing
oc create -f manifests/knative-kafka.yml -n knative-eventing

Now we should be able to deploy Kafka brokers in a brand new handyman project:

oc new-project handyman
oc create -f manifests/kafka-cluster.yml -n handyman
oc create -f manifests/kafka-topics.yml -n handyman

You'll see that the rendering-requests Kafka Topic is created with a number of 25 partitions that is matching with the maximum number of rendering workers we may have (5 x 5 tiles image).

Attention: you'll see that the rendering components are using a quite important amount of resources (4 cpu + 4.5 GB memory) be sure to have raised the Quotas or LimitRanges of your project accordingly.

Now start deploying the application components. We start with the handyman-ordering pod using a regular deployment, service and route:

oc create -f manifests/handyman-ordering-deployment.yml -n handyman
oc create -f manifests/handyman-ordering-service.yml -n handyman
oc create -f manifests/handyman-ordering-route.yml -n handyman

Then we'll deploy the handyman-rendering component, wrapping it into a Knative Service. For that, we use the kn CLI. We have used following version of the CLI:

$ kn version
Version:      v20201110-e8b26e18
Build Date:   2020-11-10 10:39:27
Git Revision: e8b26e18
Supported APIs:
* Serving
  - serving.knative.dev/v1 (knative-serving v0.18.0)
* Eventing
  - sources.knative.dev/v1alpha2 (knative-eventing v0.18.0)
  - eventing.knative.dev/v1beta1 (knative-eventing v0.18.0)

Then we create the Knative service using the rendering container image:

kn service create handyman-rendering --image docker.io/alainpham/rendering:latest \
    --env FILESERVERURL=handyman-ordering:8080/download/ --env UPLOADSERVERURL=handyman-ordering:8080/renders/ \
    --env KAFKABROKER=my-cluster-kafka-bootstrap:9092 --env JAVA_OPTIONS=-Xmx3g --env QUARKUS_HTTP_READ_TIMEOUT=60m \
    --port 8083 --request cpu=4000m,memory=4500Mi --limit cpu=4000m,memory=4500Mi \
    --concurrency-limit 1 --concurrency-target 1 -n handyman

You'll notice that we use a fair amount of resources. Also, note the concurrency-limit and target flags ensuring that each rendering pod will only receive and process 1 rendering request at a time.

Final step is now to deploy the Knative Kafka EventSource:

oc create -f manifests/kafka-source.yml -n handyman

Wait for some seconds and you should have the following topology view on the developer console:

Connect to the route of handyman-ordering component and upload a Blender file to the application:

You'll have the ability to choose from different rendering options. Once clicked the requests are distributed among the different handyman-redenring instances created by Knative eventing.

Depending on the chosen option, results are starting to appear after 30 seconds to 2 minutes. The scene tiles are aggregated in the browser canvas view: