Challenge, Easy,  on  Kubernetes

Configure a Memory-Backed emptyDir Volume with a Size Limit

Scenario

A Deployment named session-store is running in namespace cherry. The Pods use a volume named cache-volume of type emptyDir but no size limit is configured — the volume can consume unlimited node memory, which is a risk in production.

The manifest file is located at:

/home/laborant/session-store.yaml

Task

Update the cache-volume definition in /home/laborant/session-store.yaml to use a memory-backed emptyDir with a size limit:

  • medium: Memory — backs the volume with RAM using tmpfs
  • sizeLimit: 256Mi — limits the volume to 256Mi

Apply the updated manifest after making the changes.

Hint 1

medium: Memory mounts the volume as tmpfs — it uses RAM instead of disk. This is faster than disk-backed storage but the data is lost when the Pod restarts. Setting sizeLimit prevents the volume from consuming more than 256Mi of node memory.

Find the cache-volume entry under spec.template.spec.volumes in the manifest. Replace emptyDir: {} with the updated configuration.

Use kubectl apply -f /home/laborant/session-store.yaml to apply.

See the official docs: Volumes — emptyDir

Test Cases

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 configure-memory-backed-emptydir-volume-with-a-size-limit-3b7688a0

This will create a local copy of the challenge content in a directory named configure-memory-backed-emptydir-volume-with-a-size-limit-3b7688a0. You only need to do this once per challenge.

Stream your changes

labctl content push -fw challenge configure-memory-backed-emptydir-volume-with-a-size-limit-3b7688a0

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