About the Certification

CKAD focuses on running, maintaining and monitoring cloud-native applications

Init Containers : These containers run before the main container and basically prepare the environment for the main container to run.

Sidecar Containers : These run alongside the main container. It is of two types:

• Adapter Pattern - The external service, sidecar and main container exchange data through a persistent volume. Ex use-case: Like in case of Logging

• Ambassador Pattern - The main container contacts external service/volume via the sidecar pattern. Ex use-case: Proxy sidecar, main container uses proxy sidecar to contact ext. service.

  

Labels vs Metadata

Labels can be used for querying while Metadata cannot be. Querying is done via CLI or spec.selector.