elasti

Getting Started

Get started by following below steps:

Prerequisites

• Kubernetes Cluster: You should have a running Kubernetes cluster. You can use any cloud-based or on-premises Kubernetes distribution.
• kubectl: Installed and configured to interact with your Kubernetes cluster.
• Helm: Installed for managing Kubernetes applications.

Install

1. Install Elasti using helm

Use Helm to install elasti into your Kubernetes cluster.

helm install elasti oci://tfy.jfrog.io/tfy-helm/elasti --namespace elasti --create-namespace

Check out values.yaml to see configuration options in the helm value file.

2. Verify the Installation

Check the status of your Helm release and ensure that the elasti components are running:

helm status elasti --namespace elasti
kubectl get pods -n elasti

You will see 2 components running.

1. Controller/Operator: elasti-operator-controller-manager-... is to switch the traffic, watch resources, scale etc.
2. Resolver: elasti-resolver-... is to proxy the requests.

3. Setup Prometheus

We will setup a sample prometheus to read metrics from the nginx ingress controller.

helm repo add prometheus-community https://prometheus-community.github.io/helm-charts
helm repo update
helm install kube-prometheus-stack prometheus-community/kube-prometheus-stack \
  --namespace monitoring \
  --create-namespace \
  --set alertmanager.enabled=false \
  --set grafana.enabled=false \
  --set prometheus.prometheusSpec.serviceMonitorSelectorNilUsesHelmValues=false

4. Setup nginx ingress controller

We will setup a nginx ingress controller to route the traffic to the httpbin service.

helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx
helm repo update
helm install nginx-ingress ingress-nginx/ingress-nginx \
  --namespace ingress-nginx \
  --set controller.metrics.enabled=true \
  --set controller.metrics.serviceMonitor.enabled=true \
  --create-namespace

This will deploy a nginx ingress controller in the ingress-nginx namespace.

5. Setup a Service

We will use a sample httpbin service to demonstrate how to configure a service to handle its traffic via elasti.

kubectl create namespace elasti-demo
kubectl apply -n elasti-demo -f https://raw.githubusercontent.com/truefoundry/elasti/refs/heads/main/playground/config/demo-application.yaml

This will deploy a httpbin service in the elasti-demo namespace.

6. Define an ElastiService

To configure a service to handle its traffic via elasti, you’ll need to create and apply a ElastiService custom resource:

Create a file named httpbin-elasti.yaml and apply the configuration.

apiVersion: elasti.truefoundry.com/v1alpha1
kind: ElastiService
metadata:
  name: httpbin-elasti
  namespace: elasti-demo
spec:
  minTargetReplicas: 1
  service: httpbin
  cooldownPeriod: 5
  scaleTargetRef:
    apiVersion: apps/v1
    kind: deployments
    name: httpbin
  triggers:
    - type: prometheus
      metadata:
        query: sum(rate(nginx_ingress_controller_nginx_process_requests_total[1m])) or vector(0)
        serverAddress: http://kube-prometheus-stack-prometheus.monitoring.svc.cluster.local:9090
        threshold: "0.5"

7. Apply the elasti service configuration

Apply the configuration to your Kubernetes cluster:

kubectl apply -f httpbin-elasti.yaml -n elasti-demo

The pod will be scaled down to 0 replicas if there is no traffic.

8. Test the setup

You can test the setup by sending requests to the nginx load balancer service.

kubectl port-forward svc/nginx-ingress-nginx-controller -n ingress-nginx 8080:80

Start a watch on the httpbin service.

kubectl get pods -n elasti-demo -w

Send a request to the httpbin service.

curl -v http://localhost:8080/httpbin

You should see the pods being created and scaled up to 1 replica. A response from the httpbin service should be visible for the curl command. The service should be scaled down to 0 replicas if there is no traffic for 5 (cooldownPeriod in elastiService) seconds.

Uninstall

To uninstall Elasti, you will need to remove all the installed ElastiServices first. Then, simply delete the installation file.

kubectl delete elastiservices --all
helm uninstall elasti -n elasti
kubectl delete namespace elasti

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