Pods are the smallest, most basic deployable object State of the pod is pending, running, succeeded / failed Pods are instantiated Pods contains one or more containers pods are part of nodes each pod has unique IP address pod is created in node typically, same service / app containers are not deployed in same pod (port has to be unique) Pods are like minions. Pods is virtual or logical concept… pods cannot be accessed directly. network parameters within a pod are

master / Control plane Master – Api server -> POD -> Container -> Docker image –> Google Registry – Etcd -> POD -> Container -> Docker image –> Google Registry – Controller mgmr -> POD -> Container -> Docker image –> Google Registry – Schedular -> POD -> Container -> Docker image –> Google Registry – kubelet – docker – kube proxy -> POD -> Container -> Docker image –> Google Registry – kubectl – kubeadm Worker – kubelet –

Docker image contains collection of file systems (root,user,application) Docker image can contain one or many layers. rootfs layer is always present. In case of file system conflict, the top layer takes precedence. The layered file systems are identified using UUID which are created using SHA256 algorithm. tagging is used to identify specific UUID with user friendly name docker inspect command can show the UUID of various layers used in the image. docker inspect command can be used to view docker

update docker update command allows to update the allocation of computing units and scheduling algorithm based on the actual hardware resources available. docker update –cpus 0.5 –memory-swap 1073741824 –memory 1073741824 52659b1482a1 624ce71391eb wait docker wait command waits for one or more container to exit and provides the return status of the docker exit [root@ip-172-31-15-56 centos]# docker wait 4638992d83550[root@ip-172-31-15-56 centos]# [root@ip-172-31-15-56 centos]# docker wait 1852fb6244e3137[root@ip-172-31-15-56 centos]#

What is the diff between docker pause and docker unpause? docker pause and unpause allows to temporarily stop and resume the docker container process. What is the diff between docker stop and docker kill? docker stop may allow system to gracefully exist before stopping the docker (by signalling) whereas docker kill could forcefully terminate the docker container process. kill can be used in the event of system hang or similar situation.