Init Containers

• Overview: Init Containers enable seperation of concerns by providing a separate lifecycle for initialization related tasks distinct from main application containers.
• Init Containers in k8s are part of Pod definition, and they separate all containers in the Pods into two groups
  • Init Containers
  • Application Containers
• All init container are executed in sequence & all of them have to terminate sucessfully before the application containers are started up.
• Refer Here for the changeset containing sample init container code.

Sidecar

• A Sidecar container extends and enhances the functionality of a pre existing container without changing it.
• Now we can use side car
  • to export logs
  • synchronize directories
• Refer Here for the pod manifest

Adapter

• Adapter pattern takes a heterogenours containerized system and makes it confirm to conistent unified interface with standard and normailized format to be consumed by outside world.
• Adapter pattern inherits all the characteristics from Sidecar, but has the single purpose of providing adapted access to the application
• We have an application which is composed of multiple microservices written in different languages
• So we need to monitor the application i.e we want applications to expose the metrics in the same format to the monitoring tool.