atomic unit of schedulingall container in pod share the pod environment. anything attached to pod, all container can use it.it can contain one or more containers.pod can have tight coupling- loose coupling.pods are atomic, you can scale the port from 1 to many.pods are the application which can access through n/w.pods contain container. and runs as long as container run.multi container pods – main container and side car container.pod lifecycle: phase: pending –> phase: running –> phase: succeeded/failed.inter pod communication

kubelet: just like a slave. the main kubernetes agent. register node with cluster- master approves it. watches api server.kubelet will talk to api server with health status.instantiate pods – not creation. pod is the logical unit of cluster. exposes end points on 10255.container engine: does container management. ex:dockerkube proxy: it assign pod ip address, all containers in a pod shared a single ip. load balances across all pods in a service.

api server: all the feature available at api server. , front end to control plane. anything want to master , can send to api server.it can be using http, it consumes json file. internally it communicates with each other.cluster store:any req is send is stored here. internal communication(worker to master etc.) also stored here. it uses etcd (open source) to store.it should exist in etcd- source of truth.controller manager: collection of controller. node controller(all the monitoring activities), endpoints controller. watches

k8s is container orchestration toolworkload placement ,k8s helping infrastructure abstractionhelp to manage desired stateself healing, replace with desired stateautomatic rollback/rollouts – rollback the feature / versionauto scaling – 5 container to 50 container can be doneload balancing of container/podshigh speed of deployment. upgrade/ability to rollbackstorage orchestration.

FROM: The FROM instruction initializes a new build stage and sets the Base Image for subsequent instructionsRUN: The RUN instruction will execute any commands in a new layer on top of the current image and commit the results.MAINTAINER: The MAINTAINER instruction sets the Author field of the generated images.EXPOSE: The EXPOSE instruction informs Docker that the container listens on the specified network ports at runtimeENV: The ENV instruction sets the environment variable to the valueADD: The ADD instruction copies new

Block until one or more containers stop, after that it print their exit codes.root@ip-172-31-28-155:/home/ubuntu# docker wait test_httpd root@ip-172-31-28-155:/home/ubuntu# docker stop test_httpdtest_httpd root@ip-172-31-28-155:/home/ubuntu# docker wait test_httpd0

Q1. – What is the use of “docker update” commands? with example and image The docker update command dynamically updates container configuration. it prevent containers from consuming too many resources such as CPU and memory from their Docker host. ex:

Q> What is the difference between docker pause and docker unpause?docker pause command suspends all processes in the specified containers and unpause will resume all suspended processes within containers

Q.What is the differenece between docker stop and docker kill?docker stop attempts to trigger a graceful shutdown by sending the signal SIGTERM, whereas kill just kills the process by default

Q1. Explain What is Docker Container with image?Docker container image is a lightweight, standalone, application run time environment and from one docker image we can get multiple container.