In Kubernetes, the pause container serves as the "parent container" for all of the containers in your pod. The pause container has two core responsibilities. First, it serves as the basis of Linux namespace sharing in the pod. And second, with PID (process ID) namespace sharing enabled, it serves as PID 1 for each pod and reaps zombie processes.

The pause container is part of each pod that is responsible to create shared network, assign ip address within the pod for all business containers inside this pod, also the pause container shared the volume for entire pod. If the pause container is dead, Kubernetes consider the pod died and kill it and reschedule a new one.