AWS EKS with Fargate

YOGESH GOWDA G R's photo
YOGESH GOWDA G R
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4 min read

AWS EKS with Fargate

AWS Fargate is a technology that provides on-demand, right-sized compute capacity for containers. With AWS Fargate, you no longer have to provision, configure, or scale groups of virtual machines to run containers. This removes the need to choose server types, decide when to scale your node groups, or optimize cluster packing. You can control which pods start on Fargate and how they run with Fargate profiles, which are defined as part of your Amazon EKS cluster.

Fargate works by letting you deploy containers without having to set up or manage the infrastructure that hosts them. You simply tell Fargate which container images you want to run and provide some details about how much computing and memory resources should allocate to them. Then, Fargate automatically provisions the host servers for you. You pay only for the resources consumed when your containers are running. Fargate will not run on its own. We need to have ECS or EKS handle container orchestration tasks.

With AWS EKS autoscaling, we need to define the min and max number of nodes. But in Fargate, we don't have to do that. So simple yet..!

Using Fargate has its drawbacks, but we will discuss those later.

For more info on Fargate, Use the below link.

AWS Fargate - Amazon EKS

Creating Kubernetes Cluster

I am assuming you have already configured aws cli on your system and installed aws cli, eksctl and kubectl

First, let's create a Kubernetes cluster using the ekcstl command

eksctl create cluster --name demo-fargate-poc --region ap-south-1 --version 1.23 --nodegroup-name linuxgroup --node-type t2.medium --nodes 2

update kubeconfig to access the cluster

aws eks update-kubeconfig --region ap-south-1 --name demo-fargate-poc

check the nodes now. ( you should see 2 nodes ) .

kubectl get nodes

deploy a sample nginx and verify once.

kubectl  create deployment nginx --replicas=3 --image=nginx

check the pods

kubectl get pods

Once verified, let's start with Fargate.

Create a namespace to run Fargate pods

kubectl create namespace fargate-poc

Fargate Profile creation

Before you schedule pods on Fargate in your cluster, you must define at least one Fargate profile that specifies which pods use Fargate when launched.

To create a Fargate profile for a cluster with the AWS Management Console

  1. Open the Amazon EKS console at https://console.aws.amazon.com/eks/home#/clusters.

  2. Choose the cluster to create a Fargate profile for.

  3. Choose the Compute tab.

  4. Under Fargate profiles, choose to Add Fargate profile.

  5. On the Configure Fargate profile page, add the following: Name, Pod execution role ( For more information, see Amazon EKS pod execution IAM role ), and Subnets. (Only private subnets are supported for pods that are running on Fargate), Tags (optional). Choose Next.

  6. On the Configure pod selection page, do the following: Namespace (can mention multiple namespaces with wild cards like prod-* ) I have used fargate-poc . Add Kubernetes labels to the selector (infrastructure: fargate) here you are restricting which pods in that namespace to run using the Fargate profile.

  7. On the Review and Create page, review the information for your Fargate profile and choose Create.

For more info on creating a Fargate profile check the below links

Amazon EKS pod execution IAM role - Amazon EKS

For more info on how to create a Role in IAM use the below Link

Amazon EKS pod execution IAM role - Amazon EKS

Now that we have a cluster with 2 nodes and a frigate profile to provision nodes. we can go ahead and create pods matching to Fargate profile.

Below is the deployment I have used.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  namespace: fargate-poc
  labels:
    app: nginx

spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
      infrastructure: fargate

  template:
    metadata:
      labels:
        app: nginx
        infrastructure: fargate
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80

Now Check the nodes you should see the Fargate nodes running .

kubectl get nodes

the output will be something like below

fargate-ip-10-0-89-244.region-code.compute.internal

You can also define the CPU and memory values needed for the pods in yaml file. Fargate will get the CPU and memory values from there and provision the nodes accordingly. Below is an example you can use

apiVersion: v1
kind: Pod
metadata:
  name: fargate-pod-poc-
spec:
  containers:
  - name: my-nginx-container
    image: nginx
    resources:
      requests:
        cpu: 256m
        memory: 512Mi
      limits:
        cpu: 512m
        memory: 1Gi

This node vanishes as soon as the pod gets deleted.

Now coming to limitations on Fargate. Below are my findings.

  1. 20GB disk for each machine - you will get 20GB Ephermel storage for each node provisioned by using the Fargate profile, you cannot increase while using EKS. (You have the option to increase this if you are using ECS )

  2. Runs only on the private subnet of the EKS cluster.

  3. You cannot mount volumes on fargate nodes. (its simply not possible now according to aws docs)

  4. Daemonsets will not run in these nodes.

  5. For each pod, aws will provision a separate node.

You can check below link for further information and considerations.

AWS Fargate - Amazon EKS

Thank you for reading ....

aws-fargateEKS