Using ConfigMaps as mounted volumes in Kubernetes - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a ConfigMap in Kubernetes?

A ConfigMap is a Kubernetes object that stores configuration data as key-value pairs. It helps separate configuration from container images, making apps easier to manage and update.

beginner

How do you use a ConfigMap as a mounted volume in a Pod?

You create a volume in the Pod spec that references the ConfigMap, then mount that volume into a container's file system at a specific path.

intermediate

What happens to the files inside a ConfigMap volume when the ConfigMap is updated?

The files inside the mounted ConfigMap volume are updated automatically within a few seconds, so the container sees the latest config without restarting.

intermediate

Can you mount only specific keys from a ConfigMap as files in a volume?

Yes, you can specify which keys to include or rename them as files using the 'items' field in the volume definition.

beginner

Show a simple YAML snippet to mount a ConfigMap named 'app-config' as a volume at '/etc/config'.

volumes: - name: config-volume configMap: name: app-config containers: - name: app volumeMounts: - name: config-volume mountPath: /etc/config

What is the main purpose of using ConfigMaps as mounted volumes in Kubernetes?

A To schedule Pods on nodes

B To store container images

C To manage network policies

D To provide configuration files inside containers

ConfigMaps provide configuration data as files or environment variables inside containers.

Which Kubernetes object do you reference to mount a ConfigMap as a volume?

A secret volume

B persistentVolumeClaim

C volume with configMap field

D serviceAccount

You define a volume with the configMap field pointing to the ConfigMap name.

If you update a ConfigMap, what happens to the mounted files in running Pods?

A They update automatically after a short delay

B They never update until Pod restart

C They update only after deleting the Pod

D They update only after deleting the ConfigMap

Mounted ConfigMap files refresh automatically within seconds without restarting the Pod.

How can you mount only specific keys from a ConfigMap as files?

A Create a new ConfigMap with only those keys

B Use the 'items' field in the volume config

C Use environment variables only

D Mount the entire ConfigMap always

The 'items' field lets you select and rename keys to mount as files.

Where do you specify the mount path for a ConfigMap volume inside a container?

A volumeMounts.mountPath

B volumes.path

C containers.image

D metadata.name

The mountPath is set under volumeMounts in the container spec.

Explain how to mount a ConfigMap as a volume in a Kubernetes Pod and why this is useful.

Think about separating config from code and how files appear inside containers.

Describe what happens when you update a ConfigMap that is mounted as a volume in a running Pod.

Consider how Kubernetes syncs ConfigMap data to the volume.