What's the Weather?

This is a sample app meant for use with Kubernetes and/or Istio. It displays the weather from a single city (Austin, TX) or multiple cities (Austin, New York, San Francisco, Seattle).

Building

The images can be built using Docker or using Cloud Build. To build an invidual image, refer to the following example:

gcloud builds submit --tag gcr.io/[PROJECTID]/weather-frontend:1.0 frontend/

Or to build all of the images, run build-images.sh.

Deploying

There are deployment specifications for Kubernetes and Istio in manifests. Before proceeding, you will need an API key from OpenWeatherMap.

Once you have your API key, add a Secret to your Kubernetes cluster:

• kubectl create secret generic openweathermap --from-literal=apikey=[OPENWEATHERMAP-API-KEY]

Kubernetes

To deploy the app to Kubernetes (without Istio), use the following commands:

• kubectl apply -f manifests/weather-deployment.yaml

Note: the Services are not externally accessible (no Ingress resource is created) so to access weather-frontend you'll need to use port forwarding and open http://localhost:5000:

• kubectl port-forward deployment/weather-frontend 5000:5000

Kubernetes and Istio

Once you have created a Kubernetes cluster and installed Istio, you can deploy the sample app as follows.

First, enable auto-injection of the Envoy istio-proxy:

• kubectl label ns default istio-injection=enabled

Then deploy the rules first and the app second:

• kubectl apply -f manifests/weather-rules.yaml
• kubectl apply -f manifests/weather-deployment.yaml

Now grab the istio-ingressgateway Load Balancer IP address:

• INGRESSGATEWAY=$(kubectl get svc -n istio-system istio-ingressgateway -o jsonpath="{.status.loadBalancer.ingress..ip}")
• Open http://$INGRESSGATEWAY in a browser

Note: If you do not want to enable auto-injection of istio-proxy for the default namespace, you can also use istioctl to include istio-proxy in your Pods:

• kubectl apply -f <(istioctl kube-inject -f manifests/weather-deployment.yaml)

Generating Load

This repo also contains a Locust script to generate load against weather-frontend.

IMPORTANT

• The loadgenerator deployment is set to hit weather-frontend.default:5000 and not $INGRESSGATEWAY therefore the traffic is coming from within the cluster
• The loadgenerator is configured as a single replica with 5 clients randomly generating requests every 1-5s. Keep this in mind so you don't go over your OpenWeatherMap API Key quota.

To deploy loadgenerator, update FRONTEND_HOST in manifests/loadgen.yaml and then apply:

• kubectl apply -f manifests/loadgen.yaml