Challenge, Medium,  on  Kubernetes

Place One Pod per Node Without Using a DaemonSet

Scenario

You are working in the aws-ecr namespace on a Kubernetes cluster with two worker nodes.

An application must be deployed with three replicas, but the design requires that no more than one Pod runs on the same worker node.

A DaemonSet must not be used to achieve this behavior.

Tasks

  1. Create a Deployment named ecr-deployment with 3 replicas in the aws-ecr namespace.
  2. Apply the following labels to the Deployment and Pod template:
    • app: ecr-app
    • tier: backend
  3. Configure the Deployment with two containers:
    • eks-container1 using image public.ecr.aws/docker/library/httpd:alpine
    • eks-container2 using image public.ecr.aws/eks-distro/kubernetes/pause:3.10.1
  4. There should only ever be one Pod from that Deployment running on a single worker node. Use topologyKey: kubernetes.io/hostname for this.
  5. Verify the scheduling result:
    • Two Pods should be in the Running state
    • One Pod should remain in the Pending state

🧪 Test Cases

Level up your Server Side game — Join 20,000 engineers who receive insightful learning materials straight to their inbox

How to Author Challenges on iximiuz Labs

Instead of providing a subpar online editing experience, iximiuz Labs offers a helper CLI tool called labctl, allowing you to use your favorite text editor (or a full-featured IDE) to write content from the comfort of your local machine.

Install labctl CLI

curl -sf https://labs.iximiuz.com/cli/install.sh | sh

This will download and install the latest version of the labctl CLI. You only need to do this once per workstation.

Authorize labctl

labctl auth login

This will open a browser window asking you to authorize labctl to access your account. You need to do it after a fresh install of labctl and repeat it whenever the auth session expires.

Pull challenge content

labctl content pull challenge place-one-pod-per-node-without-using-a-daemonSet-a8580f90

This will create a local copy of the challenge content in a directory named place-one-pod-per-node-without-using-a-daemonSet-a8580f90. You only need to do this once per challenge.

Stream your changes

labctl content push -fw challenge place-one-pod-per-node-without-using-a-daemonSet-a8580f90

Run this command in a separate terminal to continuously upload your changes to the server while editing the challenge in your favorite text editor or IDE.

You can also use labctl to create, list, and delete your content. Learn more about the available commands: labctl content --help

Start challenge